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1
Knutsen, Hege. "Characterization of GaN:ZnO p-n junctions." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13262.
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In this master thesis, thin lms of ZnO doped with various cobalt concentra-tions have been grown using Pulsed Laser Deposition (PLD). This growthtechnique is preferred because it is able to grow thin lms from a targetmaterial without changing the elemental ratios from the target. The targetsusing during deposition are sintered pellets of ZnO doped with cobalt, withdoping concentrations of 10, 20 and 30 %.The material was chosen because of its potential for Intermediate BandSolar Cells (IBSC). IBSC is a new concept which aims to create solar cellswhich have higher eciencies than the solar cells available today. From de-tailed balance theory, the concept of intermediate band solar cells shows apotential of a 86 % eciency limit under perfect conditions, which is remark-able compared to the conventional silicon solar cell devices on the markettoday with a eciency limit of 41 %.A series of ZnO thin lms of 10, 20 and 30 % cobalt concentration weredeposited by PLD on a sapphire substrate. These lms were, together with asimilar series containing 1,2 and 5 % cobalt concentration deposited on bothsilicon and sapphire substrates, characterized using Scanning Electron Mi-croscopy (SEM), Energy Dispersive X-ray (EDX) Microanalysis, X-ray Pho-toelectron Spectroscopy (XPS), Hall measurements, X-ray diraction (XRD)and optical transmission spectroscopy.In addition, an attempt to make Schottky diodes of the cobalt dopedZnO thin lms and a p-IB-n junction using GaN:Mg and ZnO:Al as the p-and n- emitter was done. These intermediate band solar cell devices weregoing to be studied by recording dark and illuminated current-voltage (I-V)characteristics.The focus in the study has been to determine which cobalt doping con-centration gives the desired properties for use of ZnO:Co in an intermediateband solar cell device, and to study how a solar cell device with an inter-mediate band material can be realized. The experiments were carried outat NTNU NanoLab, NTNU Department of Physics, NTNU Department ofElectronics and Telecommunications and SINTEF Oslo.Optical transmission spectroscopy and XPS showed that the cobalt inthe ZnO:Co lms were Co2+. This indicates that cobalt is substituting forzink in the ZnO lattice. XRD showed the crystal structure to be c-orientedwith reasonable order. The carrier concentration in the ZnO:Co lms were inthe order of 1018- 1019, decreasing with increasing cobalt concentration. Theresistivity in the samples increased with increasing doping concentration.Investigation of the GaN:Mg wafer showed that it did not have the desiredproperties for device fabrication as it showed n-type conductivity insteadof p-type. The Schottky diodes made of Au-ZnO:Co and Pt-ZnO:Co did not show diode behavior because of surface states in ZnO:Co making ohmiccontacts.
2
Fearn, Michael James. "Preparation and properties of P-N molecular junctions." Thesis, University of Manchester, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580591.
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Abstract Over the last few decades there has been a huge interest in the synthesis of novel conjugated small molecules and polymers due to their immense potential in the electronics industry. To date, inorganic based systems have continued to dominate the market. However, there is a growing demand for new low-cost materials for a range of new electronics applications. At the present time, only devices based upon organic light emitting diodes (OLEDs) have begun to demonstrate their capabilities in the commercial market. For other devices such as organic photovoltaic devices (OPVDs) and organic field-effect transistors (OFETs) there are still numerous technical issues that need to be overcome. In order to address issues such as charge transport and charge separation, this thesis focuses on the synthesis and characterisation of novel hole transport (p-type) and electron transport (n- type) materials as well as laying down the foundations for building molecular p-n junctions. The deployment of such molecular p-n junctions could have particularly important implications for OPVDs where charge separation and recombination are fundamentally important processes. Chapter one introduces the reader to the field of organic electronics, and aims to give a broader understanding about the various devices, and the types of semiconductor materials that are important for such applications. Chapter two describes the preparation and characterisation of a small library of simple p and n-type molecules from which subsequent studies will be based. In chapter three, the preparation of novel semiconductor materials based upon symmetrical and asymmetrical [9,9']bifluorenylidenes, ~4,4'-dicyclopenta[2, 1-b;3,4-b']dithiophenes and 1,4-bis(2,2'- biphenylene)-1 ,3-butadienes is discussed, as well as the characterisation of representatives from this group. Chapter four examines the synthesis and characterisation of semiconductor materi- als based around spirobifluorene, and demonstrates how such synthetic strategies can be further applied to the preparation of novel dispirodifluorene semiconductor materials. Finally in chapter five, an overview of the project is presented, as well as some suggestions for future work. This tonn, when completed, should be submitted to EPS GRADUATE SCHOOL, ROOM 843, SACKYILLE sr, UNIVERSITY OF MANCHESTER, MANCHESTER, M60 lQD Page 5 April 2005
3
Habib, Mohammad Humayun. "Semiconductor P-N Junction Space Charge Region Capacitance." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4589.
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The classical capacitance voltage characteristics based on the depletion approximation, is adequate at reverse bias, but introduces errors at high forward bias. Because of its inherent simplicity and compactness this classical depletion model is well studied and widely used in circuit simulators. In this work, a new model for the semiconductor space charge region (SCR) capacitance, based on physical justification, will be derived. This new model takes three input parameters, C0 , Vbi and m, thus eliminating the fitting parameter FC currently used in SPICE. This new model is applicable for any applied voltage and will be compared with the SCR capacitance extracted from the numerical device simulator PISCES, and with the SCR capacitance models proposed by Gummel and Poon and by DeGraaff and Klaassen.
4
Samutpraphoot, Polnop. "Anomalous Hall effect and persistent valley currents in graphene p-n junctions/." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92691.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 39-40).<br>Dirac particles can exhibit Hall-like transport induced by Berry's gauge field in the absence of magnetic field. We develop a detailed picture of this unusual effect for charge carriers in graphene nanostructures. The Hall effect is nonzero in each valley but is of opposite signs in different valleys, giving rise to charge-neutral valley currents. Our analysis reveals that p-n junctions in graphene support persistent valley currents that remain nonzero in the system ground state (in thermodynamic equilibrium). The valley currents can be controlled via the bias and gate voltages, enabling a variety of potentially useful valley transport phenomena.<br>by Polnop Samutpraphoot.<br>S.B.
5
He, Jianqing. "Investigation of transport mechanisms for n-p-n InP/InGaAs/InP double heterojunction bipolar transistors." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44645.
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<p>A more complete model for InP/InGaAs Double Heterojunction Bipolar
Transistors (DHBT) is obtained in this thesis by physically analyzing the transport
process of the main current components. The potential distribution of the energy
barrier constitutes a fundamental analytical concept and is employed for applying
the diffusion, the thermionic emission, and the tunneling theories in investigating the
injection mechanisms at the e-b heterojunction interface. The diffusion transport is
considered first for electron injection from the emitter into the base. The thermionic
emission is applied properly at the point of maximum potential energy as one
of the boundary conditions at that interface. A suitable energy level is selected with
respect to which the energy barrier expression is expanded for the calculation of the
tunneling probability. The first "spike" at the conduction band discontinuity is
described as the potential energy for the injected electrons to obtain kinetic energy
to move into the base region with a substantially high Velocity. The electron blocking
action of the second "spike" at the bâ c junction is also analyzed by considering the
transport Velocity with which electrons are swept out of that boundary. Based on the
material parameters recently reported for both InP and InGaAs, computations of the nI
current components are carried out to provide à characteristics in good agreement
with the reported experimental results.<br>Master of Science
6
Aygun, Seymen Murat. "Gas Sensors Based on Ceramic p-n Heterocontacts." Ames, Iowa : Oak Ridge, Tenn. : Ames Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/837264-2ckydm/webviewable/.
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Thesis (M.S.); Submitted to Iowa State Univ., Ames, IA (US); 19 Dec 2004.<br>Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2498" Seymen Murat Aygun. US Department of Energy 12/19/2004. Report is also available in paper and microfiche from NTIS.
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Chaudhry, Wahid. "Vertical transport through n-InAs/p-GaSb heterojunctions at high pressures and magnetic fields." Thesis, University of Oxford, 1999. http://ora.ox.ac.uk/objects/uuid:355f36e2-cae2-4dad-8639-ed9f618c98ea.
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The conduction band of InAs lies lower in energy than the GaSb valence band. In order to preserve continuity of the Fermi level across the interface, charge transfer takes place resulting in a confined quasi two dimensional electron gas (2DEG) in the InAs and a confined quasi two dimensional hole gas (2DHG) in the GaSb. This study is an investigation into the vertical transport in an n-InAs/p-GaSb single heterojunction (SHET). Application of a forward bias (InAs negative with respect to GaSb) increases the 2DEG and 2DHG concentrations and, therefore, their confinement energies. Eventually a critical bias is reached where the electron confinement energy moves above the hole confinement energy (the theoretical voltage induced semimetal/semiconductor transition V<sub>c</sub>). Any subsequent increase in voltage is expected to result in a current decrease, and a region of negative differential resistance (NDR) should occur. The SHET can be grown with two distinct interface types, 'InSb-like' and 'GaAs-like'. This in turn affects the vertical transport characteristics of each type. Experimental IV traces at various pressures are compared with the corresponding results from sophisticated self-consistent band profile calculations taking into account band mixing effects for the first time through a k.p theory framework. Experimental IV traces of the SHETs under a magnetic field parallel to the interface are also compared with results from calculations that take into account the coupling of the growth and in-plane electron and heavy hole motions. Both sets of analysis support earlier conclusions that NDR occurs after V<sub>c</sub> for both interfaces, and that each interface supports a different conduction mechanism. Evidence of multiple phonon processes occurring in both sample types is observed for the first time and is proposed to reconcile the above experimental observations with theory. This data is found to offer explanations for a number of other observations. Field perpendicular to the interface leads to the observation of features beyond the NDR region in both sample types. In samples with an 'InSb-like' interface, applying additional hydrostatic pressure leads to very strong features beyond the main NDR. Through a complex self-consistent decoupled model taking into account electrons and heavy holes, all these features are proposed to be due to a filling of an integer number of Landau levels. The band profile is predicted to alter dramatically at this point. The same model explains the observation of weaker features at 1 bar at high fields (~ 40T). A variation of NDR position is found with a rotation of an-plane field.
8
Lotus, Adria Farhana. "Synthesis of Semiconducting Ceramic Nanofibers, Development of P-N Junctions, and Bandgap Engineering by Electrospinning." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1248121308.
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Mei, Xiangyang. "Preparation of pyramidal textured GaP p-n junctions and their applications to alpha radio-voltaic cells, ARVCs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33972.pdf.
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Ryoo, Kunkul. "A study of effect of precipitates and lattice defects on the electrical performance of P-N junctions /." Full text open access at:, 1986. http://content.ohsu.edu/u?/etd,118.
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Huang, Yan. "Some studies of structural and point defects in gallium nitride and their influence in determining the properties of the bulk material, its Schottky contacts, P-N junctions and heterostructures." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31559670.
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Huang, Yan, and 黃燕. "Some studies of structural and point defects in gallium nitride and their influence in determining the properties of the bulk material,its Schottky contacts, P-N junctions and heterostructures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31559670.
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Anderson, Tom Harper. "Optoelectronic simulation of nonhomogeneous solar cells." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25892.
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This thesis investigates the possibility of enhancing the efficiency of thin film solar cells by including periodic material nonhomogeneities in combination with periodically corrugated back reflectors. Two different types of solar cell are investigated; p-i-n junctions solar cells made from alloys of hydrogenated amorphous silicon (a-Si:H) (containing either carbon or germanium), and Schottky barrier junction solar cells made from alloys of indium gallium nitride (InξGa1-ξN). Material nonhomogeneities are produced by varying the fractions of the constituent elements of the alloys. For example, by varying the content of carbon or germanium in the a-Si:H alloys, semiconductors with bandgaps ranging from 1:3 eV to 1:95 eV can be produced. Changing the bandgap alters both the optical and electrical properties of the material so this necessitates the use of coupled optical and electrical models. To date, the majority of solar cell simulations either prioritise the electrical portion of the simulation or they prioritise the optical portion of the simulation. In this thesis, a coupled optoelectronic model, developed using COMSOL Multiphysics®, was used to simulate solar cells: a two-dimensional finite-element optical model, which solved Maxwell's equations throughout the solar cells, was used to calculate the absorption of incident sunlight; and a finite-element electrical drift-diffusion transport model, either one- or two-dimensional depending on the symmetries of the problem, was used to calculate the steady state current densities throughout the solar cells under external voltage biases. It is shown that a periodically corrugated back reflector made from silver can increase efficiency of an a-Si:H alloy single p-i-n junction solar cell by 9:9% compared to a baseline design, while for a triple junction the improvement is a relatively meagre 1:8%. It is subsequently shown that the efficiency of these single p-i-n junction solar cells with a back reflector can be further increased by the inclusion of material nonhomogeneities, and that increasing the nonhomogeneity progressively increases efficiency, especially in thicker solar cells. In the case of InξGa1-ξN Schottky barrier junction solar cells, the gains are shown to be even greater. An overall increase in efficiency of up to 26:8% over a baseline design is reported.
14
Freitas, Aliliane Almeida de. "Propriedades estruturais e eletrônicas de nanotubos de carbono, BN e híbridos BxCyNz: um estudo por primeiros princípios." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/9518.
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Previous issue date: 2015-03-06<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>In the present work, we use first-principles calculations based on density functional theory, as
implemented in the SIESTA code, to investigate the changes in the structural and electronic properties
of the carbon, BN, and hybrid BxCyNz nanotubes produced by one or two of the following
mechanisms: doping with carbon atoms, the application of external electric fields, by flattening
of the cross section, the encapsulation of a carbon nanowire or the adsorption of hydrogen atoms
(hydrogenation).
We start with the study of double-walled boron nitride nanotubes (DWBNNTs), zig-zag and
armchair, doped with carbon atoms, with chiral vectors (8,0)@(16,0) and (5,5)@(10,10), respectively.
Two types of doping were considered: one C atom substituting a B atom on the inner
wall (IW) and one C atom substituting a N atom on the outer wall (OW), which we call of
CB[IW]@CN[OW], and the opposite situation results in CN[IW]@CB[OW]. In this sense, we generate
a (type-p semiconductor)@(type-n semiconductor) and a (type-n semiconductor)@(type-p semiconductor),
where the resulting DWBNNTs can be thought of as p-n junctions. At the same time,
we apply an external electric field, with magnitude of 0,3 V/Å, in different directions, namely,
perpendicular (Ey), parallel (Ex), and antiparallel (Ex) to the line formed by the dopants. Thus,
depending on the direction of the applied field, we observe an increase or decrease in the band
gap energy between the defect levels (Eig), and such cases are related to the reverse and direct
polarization of the p-n junction, respectively.
Afterwards, we study the insertion of a carbon nanowire (CNW) inside a (10.0) zigzag carbon
nanotube and inside a (10.0) zig-zag BN nanotube. Such systems were called CNW@SWCNT and
CNW@SWBNNT, respectively. We produce the flattening of the nanotubes and verify the behavior
of the atomic structure of the nanowire as the flattening of the nanotube increases. From the
obtained results, it was possible to conclude that, for both CNW@SWCNT and CNW@SWBNNT,
there is a critical distance dc (distance between the parallel planes of the flattened nanotubes (d)),
with the value of 3.60 Å, so that we can summarize our findings as follows: in the case d > dc,
the carbon nanowire does not undergo any deformation; and in the reverse case (d < dc), the carbon
nanowire binds to the wall of the nanotube and undergoes deformations. Regarding the electronic
properties, we verify that the encapsulation of the CNW inside the SWCNT and SWBNNT, produces
a significant reduction of the band gap energy (Eg) of such systems. Moreover, we observe
ABSTRACT viii
the creation of Dirac points for some flattening ratios of the nanotubes.
Finally, we carry out a study on the adsorption of hydrogen atoms (hydrogenation) on the surface
of double-walled boron nitride nanotubes (DWBNNTs) and hybrid nanotubes of boron nitride
and carbon (DW(BN)xCyNTs). Due to the fact that the nanotubes have two walls, we consider the
following cases: (i) coverages of 2H, 4H, 8H, 12H, and 16H on the inner wall, (ii) coverages of
2H, 4H, 8H, 16H, and 32H on the outer wall, and (iii) coverages of 2H, 4H, 8H, 16H, and 32H on
both walls. Curiously, we find that for all hydrogen coverages considered, a strong deformation
occurs in the hydrogen regions, causing the cross section of the nanotubes take different polygonal
shapes: ellipsoidal, rectangular, hexagonal or octahedral. For coverages of 16H and 32H only on
the outer wall, we observe that some hydrogens desorbed from the wall forming isolated H2 molecules
without preferential orientation. We verify that, in some cases, the bond angles between
the B, N and H or C and H atoms exhibit characteristics of the sp3 hybridization. Regarding the
structural stability, we verify that the adsorption of H atoms in DWBNCNTs is more favorable
than in DWBNNTs. Moreover, we conclude that is possible to control the band gap energy of the nanotubes through the hydrogen coverage.<br>No presente trabalho, usamos cálculos de primeiros princípios baseados na Teoria do Funcional
da Densidade, como implementado no código SIESTA, para investigarmos as alterações nas
propriedades estruturais e eletrônicas de nanotubos de carbono, de BN e híbridos BxCyNz, produzidas
por um ou dois dos seguintes mecanismos: dopagem com átomos de carbono, aplicação de
campos elétricos externos, pelo achatamento da secção transversal, encapsulamento de um nanofio
de carbono ou pela adsorção de átomos de hidrogênio (hidrogenação).
Iniciamos com o estudo de nanotubos de nitreto de boro de parede dupla (DWBNNTs), zig-zag
e armchair, dopados com átomos de carbono, com vetores quirais (8,0)@(16,0) e (5,5)@(10,10),
respectivamente. Duas situações de dopagem foram consideradas: um átomo de C substituindo um
átomo de B na parede interna (IW) e um átomo de C substituindo um átomo de N na parede externa
(OW) a qual chamamos de CB[IW]@CN[OW], e a situação oposta resulta em CN[IW]@CB[OW]. Neste
sentido, construímos um (semicondutor do tipo-p)@(semicondutor do tipo-n) e um (semicondutor
do tipo-n)@(semicondutor do tipo-p) onde os DWBNNTs resultantes podem ser pensados como
junções p-n. Paralelamente, aplicamos um campo elétrico externo, com magnitude de 0,3 V/Å, em
diferentes direções, a saber, perpendicular (Ey), paralelo (Ex) e anti-paralelo (Ex) a linha formada
pelos dopantes. Assim, dependendo da direção do campo aplicado, observamos um aumento ou
diminuição do gap de energia entre os níveis de defeitos (Eig) e tais casos estão relacionados a
polarização reversa e direta da junção p-n, respectivamente.
Em seguida, estudamos a inserção de um nanofio de carbono (CNW) no interior de um nanotubo
de carbono e de BN, ambos com vetor quiral (10.0). Tais sistemas foram chamados de
CNW@SWCNT e CNW@SWBNNT, respectivamente. Nós produzimos o achatamento dos nanotubos
e verificamos o comportamento da estrutura atômica do nanofio a medida que o achatamento
do nanotubo aumenta. A partir dos resultados obtidos, foi possível concluir que para ambos
os CNW@SWCNT e CNW@SWBNNT, existe uma distancia crítica dc (distância entre os planos
paralelos dos nanotubos achatados (d)), com um valor de 3.60 Å, de tal forma que nós podemos
resumir as nossas descobertas como: no caso de d > dc, o nanofio de carbono não sofre nenhuma
deformação; e no caso reverso (d < dc), o nanofio de carbono liga-se a parede do nanotubo e sofre
deformações. Em relação as propriedades eletrônicas, verificamos que o encapsulamento do CNW
nos SWCNT e SWBNNT, produz uma significativa redução do gap de energia (Eg) de tais sisteRESUMO
vi
mas. Além disso, observamos a formação de pontos de Dirac para algumas taxas de achatamento
dos nanotubos.
Por último, nós realizamos um estudo da adsorção de átomos de hidrogênio (hidrogenação)
sobre a superfície de um nanotubo de parede dupla de nitreto de boro (DWBNNTs) e um nanotubo
híbrido de nitreto de boro e carbono (DW(BN)xCyNTs). Devido ao fato dos nanotubos possuírem
duas paredes, consideramos os seguintes casos: (i) coberturas de 2H, 4H, 8H, 12H e 16H na parede
interna, (ii) coberturas de 2H, 4H, 8H, 16H e 32H na parede externa e (iii) coberturas de 2H, 4H,
8H, 16H e 32H em ambas as paredes. Curiosamente, verificamos que em todas as coberturas de
hidrogênio consideradas, uma forte deformação ocorre nos locais de hidrogênio, fazendo a secção
transversal dos nanotubos se transformar em diferentes formas poligonais: elipsoidal, retangular,
hexagonal ou octaedral. Para coberturas de 16H e 32H apenas na parede externa, observamos que
alguns hidrogênios se dessorveram da parede formando moléculas de H2 isoladas sem orientação
preferencial. Verificamos que em alguns casos, os ângulos de ligação entre os átomos de B, N e H
ou C e H exibem características da hibridação sp3. Com relação a estabilidade estrutural, verificamos
que a adsorção de átomos de H em DWBNCNTs é mais favorável do que em DWBNNTs.
Ademais, concluímos que é possível controlar o gap de energia dos nanotubos através da cobertura
de hidrogênio.
15
Abid, Kamran. "Gated lateral silicon p-i-n junction photodiodes." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2873/.
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Research in silicon photonics has recently seen a significant push to develop complete silicon-based optical components for optical communications. Silicon has shown its potential to overcome the bandwidth limitations of microprocessor interconnect, whereas, the silicon platform has already displayed the benefits of low manufacturing costs and CMOS compatibility. The work on “gated lateral silicon p-i-n junction photodiodes” has demonstrated the silicon potential, to detect optical radiations, compatibility to standard CMOS process flow and tuneable spectral response. The lateral structure of gated p-i-n junction photodiodes contributes to high responsivity to short wavelength radiations in these single and dual gate devices. The final objective of this work was to develop high responsivity, CMOS-compatible silicon photodiodes, where the spectral response can be modulated. The lateral p-i-n junction architecture led to high responsivity values, whereas, the MOS gate structure became the basis for tuneable spectral response. The MOS gate structure, made the devices appear as a transistor to the surrounding circuitry and the gate structure in dual gate devices can be used to modulate the spectral response of the device. Single gate devices showed higher responsivity values and comparatively high blue and ultraviolet (UV) response as compared to conventional photodiodes. Surface depletion region in these devices is utilized by placing a MOS gate structure and by patterning an integrated metal grating to detect polarized light. Single and dual gate devices with two variations were fabricated to characterise the device response. Novel lateral architecture of p-i-n junction photodiodes provides a surface depletion region. It is generally anticipated that photodetectors with surface depletion region might produce higher noise. In these devices the surface depletion region has a lateral continuation of gate dielectric which acts as a passivation layer and thus considerably reduced the noise. Physical device modelling studies were performed to verify the experimentally obtained results, which are provided in the relevant measurement chapters. In these devices the speed of operation is a compromise over the high responsivity, CMOS compatibility and tuneable spectral response.
16
Yang, Jing. "P-n junction dopant profiling using scanning capacitance microscopy /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18333.pdf.
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Hu, Yujie. "Magnetic Diode-From p-n Junction to Ohmic Contact." VCU Scholars Compass, 2004. http://scholarscompass.vcu.edu/etd_retro/60.
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This paper reviews the analytical strategy employed in conventional p-n junction. Then it goes through the analysis of magnetic p-n junction in the same strategy, which makes the review of magnetic p-n junction succinct. I-V equation of magnetic diode is the result of the p-n junction analysis. However, of great importance is to form an acceptable ohmic contact on magnetic diode, which is assumed to be ideal during the magnetic p-n junction analysis. The paper moves on to ohmic contact for magnetic diode, with the example of GaN based magnetic material. With the calculation of the shift of Fermi level in n-GaN with band splitting, conventional ohmic contact structure for n-GaN can be employed to magnetic n-GaN. Experiments from one group prove it. Ohmic contact optimization experiment on n-GaN is present. Ni/Au deposition on n-GaN shows an acceptable ohmic contact. The outlook part points out that the way for research on Schottky diode on magnetic material is partially paved by contents included in this paper.
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Lavery, Jeffrey B. "Quantum tunneling model of a p-n junction in Silvaco." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Sept/08Sep%5FLavery.pdf.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, September 2008.<br>Thesis Advisor(s): Michael, Sherif. "September 2008." Description based on title screen as viewed on November 6, 2008. Includes bibliographical references (p. 97-98). Also available in print.
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Melo, Sánchez Claudia de. "Croissance sélective de Cu2O et Cu métallique par dépôt par couche atomique sur ZnO et leur application en optoélectronique." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0040.
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Dans ce travail, après l’état de l’art et la présentation de méthodes de synthèse et d’analyse, nous présentons des résultats sur la croissance sélective de Cu2O et Cu métallique par dépôt par couche atomique (ALD) sur ZnO, ZnO dopé à l’Al (AZO) et α-Al2O3. Nous mettons en évidence la possibilité de déposer de façon sélective Cu métallique ou Cu2O, en contrôlant la température de dépôt et la conductivité ou la densité des défauts ponctuels au sein du substrat. Un procédé sélectif local de dépôt par couche atomique (AS-ALD) a été mis en évidence sur une bicouche à motifs composée de zones de ZnO de faible conductivité et de régions d’AZO de forte conductivité. De plus, l'AS-ALD permet la fabrication de nano-jonctions à base de Cu2O/ZnO /AZO/Cu, dont le comportement de jonction p-n a été confirmé par microscopie à force atomique à pointe conductrice (C-AFM). Les mécanismes liés à la croissance sélective locale sont également discutés. Dans la seconde partie de cette thèse, des nanoparticules de Cu (NP) ont été déposées par ALD sur des couches minces de ZnO. Les NP de Cu présentent une résonance plasmon de surface localisée caractérisée par ellipsométrie. La position de la bande de résonance plasmon est ajustable entre les régions visible et infrarouge du spectre électromagnétique en gérant la taille des particules et leur espacement par l’intermédiaire du temps de dépôt. Le système Cu NP/ZnO montre une photo-réponse dans le visible grâce à la génération d'électrons chauds à la surface des NP de Cu et l'injection dans la bande de conduction de ZnO. Finalement, des hétérojonctions Cu2O/ZnO semi-transparentes ont été fabriquées par ALD et pulvérisation cathodique. Les hétérojonctions présentent une photo-réponse autoalimentée sous éclairement, des temps de réponse rapides et une transparence élevée dans le visible, ce qui est prometteur pour des applications dans les domaines de l’électronique transparente, la photo-détection et le photovoltaïque<br>In this work we present the results on the selective growth of Cu2O and metallic Cu by atomic layer deposition (ALD) on ZnO, Al-doped ZnO (AZO) and α-Al2O3 substrates. It was possible to tune the deposited material (Cu or Cu2O) by controlling the deposition temperature, and the substrate conductivity/density of donor defects. An area-selective atomic layer deposition (AS-ALD) process was demonstrated on a patterned bi-layer structure composed of low-conductive ZnO, and highly-conductive AZO regions. Furthermore, the AS-ALD allows the fabrication of Cu2O/ZnO/AZO/Cu-back-electrode nanojunctions, as confirmed by conductive atomic force microscopy (C-AFM). The mechanism behind the temperature and spatial selectivities is discussed. In a second part of this thesis, Cu nanoparticles (NP) were deposited by ALD on ZnO thin films. The Cu NP exhibit a localized surface plasmon resonance, tunable from the visible to the near-infrared regions, as confirmed by spectroscopic ellipsometry. An enhanced visible photo-response was observed in the Cu NP/ZnO device thanks to the hot-electron generation at the surface of the plasmonic Cu NP and transfer into the conduction band of ZnO. Finally, semi-transparent Cu2O/ZnO heterojunctions were fabricated by ALD and reactive magnetron sputtering. The heterojunctions present a stable self-powered photo-response under 1 Sun illumination, fast response times and high transparency in the visible region, which is promising for all-oxide transparent electronics, photodetection and photovoltaics
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Styrov, V. V., S. V. Simchenko, and V. N. Golotyuk. "Chemo-emf in the silicon solar cell exposed to low-energy hydrogen atoms." Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20602.
Full textAbstract:
A new reactive gas-semiconductor system is experimentally found and examined
for the electron-hole pairs (e-h pairs) generation in the semiconductor due to exoergicty
of a surface chemical reaction. This system is “atomic hydrogen-crystalline silicon”. The
p-n silicon homojunction was used to produce chemo-emf and chemicurrent in the semi-
conductor system due to e-h pairs creation. The ideal geometry of the semiconductor
system would require the top semiconductor layer be of a nanosized thickness since only
the upper layer of the semiconductor is involved in chemical excitation. To make the
beginning of a research we howere harnessed the commercial silicon solar cell fabricat-
ed with the certain technological changes to have a bare semiconductor surface. A spe-
cial procedure was worked out to prepare the silicon surface free of the blocking layer of
silicon oxide.
The chemo-emf in the open circuit up to a few mV and the short circuit chemicur-
rent up to the record 700 nA were achieved that are the promising magnitudes to pave a
way for direct chemical energy to electrical energy conversion by semiconductor sys-
tems.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20602
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Gardner, Neil Robin. "Electrical characteristics of silicon-doped gallium arsenide lateral P-N functions." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298294.
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Šalucha, Darius. "Passivation of the p-n junction edge in high-power semiconductor silicon devices." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20090707_154834-90672.
Full textAbstract:
Thin dielectric passivation layer is one of the basic construction elements in semiconductor device technology. There are few materials, from which the layers may be manufactured. They are oxides mainly, with Si02 as the most popular of them, although, the phosphor- and boron-silicon glasses are used as passivation layers, too. In choosing a passivant of power thyristors and diodes, there are two important considerations in addition to the usual requirement for providing uniform high breakdown voltage via substrate. One consideration is the thermal stability of the passivant to subsequent high-temperature processes. The other consideration is the bias-temperature stability of the passivation layers affecting the operation life expectancy of a device. In the technology of thyristors and diodes on silicon substrates the bias-breakdown voltage is not uniform over substrate due to non-homogeneity of passivated surface of the p-n junction.
In this work, passivation of moat surface by means of electrochemical etching, formation of hydrogen-rich porous silicon layers and glass in-melting steps has been investigated. Passivation quality was controlled by the measurements of surface recombination characteristics after each technological step using a non-invasive technique, which employed microwave probed photoconductivity transients (MW-PCT). It has been shown that electrochemical etching - glass melting steps involved in passivation technological procedures resulted in a decrease of... [to full text]<br>Puslaidininkinių prietaisų pramušimo įtampos valdymas formuojant griovelį periferiniame perimetre yra viena iš labiausiai paplitusių technologinių operacijų, gaminant galios diodus bei tiristorius Si pagrindu. Aukštavolčių didelės galios puslaidininkinių prietaisų, kurie dirba kelių tūkstančių amperų diapazone, o uždarymo įtampa iki kelių tūkstančių voltų, didelė problema elektrinio lauko pasiskirstymas ties kristalo briauna, kur p-n sandūra išeina į paviršių ir kur vyksta griūtinis krūvininkų skaičiaus didėjimas. Darbo stabilumui užtikrinti būtina pasyvuoti paviršių kristalo periferijoje, ant profiliuoto krašto.
Šiame darbe išanalizuota galingų puslaidininkinių struktūrų konstrukcija, pagrindinės charakteristikos, parametrų tarpusavio ryšis, taip pat technologinis procesas ir jo ypatumai. Išanalizuotos technologinio gamybos maršruto silpniausios pozicijos. Nustatyta izoliacinių griovelių ėsdinimo charakteristikų priklausomybė nuo ėsdiklio sudėties, nuo ėsdinimo įrenginio struktūros ir nuo ėsdiklio temperatūros kitimo. Sukurta stiklo pasyvacijos difuzinės krosnies monitoringo sistema, kuri skirta aukštų temperaturų ir dujų srautų matavimui proceso metu. Rekombinacijų charakteristikų kitimo pagalba, matuojant be kontakte MW-PCT technika, įvertinama izoliacinių griovelių pasyvacijos kokybė. Technologiniame gamybos maršrute, po izoliacinio griovelio ėsdinimo operacijos, prieš stiklo pasyvaciją sudarinėjamas porėtojo silicio sluoksnis, taip pat siūloma įvesti homogeniškumo... [toliau žr. visą tekstą]
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Singh, Surjeet. "Mathematical Modeling of a P-N Junction Solar Cell using the Transport Equations." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1496054495555896.
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Walker, Nathan Thomas. "A Density Functional Theory and Many Body Perturbation Theory Based Study of Photo-Excited Charge Separation in Doped Silicon Nanowires with Gold Leads: Toy Models for the Photovoltaic Effect." Thesis, North Dakota State University, 2020. https://hdl.handle.net/10365/31785.
Full textAbstract:
We analyze a toy model for p-n junction photovoltaic devices by simulating photoexcited state dynamics in silicon nanowires. One nanowire is approximately circular in cross section with a diameter of d = 1.17 nm. The other has an approximately rhombic cross-section with d1 = 1.16 nm and d2 = 1.71 nm. Both nanowires have been doped with aluminum and phosphorus atoms and capped with gold leads. We use Boltzmann transport equation (BE) that includes phonon emission, carrier multiplication (CM), and exciton transfer. BE rates are computed using non-equilibrium finite-temperature many-body perturbation theory (MBPT) based on Density Functional Theory (DFT) simulations, including excitonic effects from Bethe-Salpeter Equation. We compute total charge transfer amount generated from the initial photoexcitation and find an enhancement when CM is included. In particular, we see between 78% and 79% enhancement in the smaller wire, while we see 116% enhancement in the larger nanowire
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Akaike, Kouki, kaname Kanai, Yukio Ouchi, and Kazuhiko Seki. "Influence of ionization energy change on valence band offset in organic p-n junction." American Institute of Physics, 2009. http://hdl.handle.net/2237/14155.
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Medvid, A., P. Onufrijevs, G. Mozolevskis, and E. Dauksta. "Two-stage of Nanocones Formation by Laser Radiation on the Surface of Semiconductors." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34984.
Full textAbstract:
In this work we study mechanism of nanocones formation on a surface of elementary semiconductors
by Nd:YAG laser radiation. A new mechanism of p-n junction formation by laser radiation in the
elementary semiconductor as a first stage of nanocones formation is proposed. We explain this effect in
following way: p-n junction is formed by generation and redistribution of intrinsic point defects in
temperature gradient field – the Thermogradient effect, which is caused by strongly absorbed laser
radiation. According to the Thermogradient effect, interstitial atoms drift towards the irradiated surface,
but vacancies drift to the opposite direction – in the bulk of semiconductor. Since interstitials in Ge crystal
are of n-type and vacancies are known to be of p-type, a n-p junction is formed. The mechanism is
confirmed by appearance of diode-like current-voltage characteristics after i-Ge irradiation crystal by laser
radiation. The second stage of nanocones formation is laser heating up of top layer enriched by interstitial
atoms with its further plastic deformation due to compressive stress caused by concentration of
interstitials in the top layer and vacancies in the buried layer.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34984
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Jafarov, M. A., and E. F. Nasirov. "Zn1-xCdxS Nanoparticles, Nanofilms, Nanoscale Junction for SolarCells." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34894.
Full textAbstract:
The In this work the results on the investigation of the precularity near the solar spectrum region, of
Zn1-xCdxS nanoparticles, nanofilms, nanoscale p-n and heterojunction prepared on glass-ceramic ad alumminium
substrates by precipitation from aqueous solutions are presented. The temperature dependence of
dark and light conductivity, spectrum and optical quenching of primary and impurity photoconductivity
are investigated. The obtained results show that when controlling ionic composition and heat-treatment
(HT) conditions, one can purposely control the properties of Zn1-xCdxS (0 x 0.6) films, achieve the appropriate
degree of compensation of different recombination levels and traps attributed to intrinsic defects or
impurities, which result in high level of photoelectrical parameters near the IR region. Just after deposition
the photoconductivity spectrum maximum of Cd1-xZnxS (0 x 0.6) films is observed at
1 = 0.445 0.495 m versus the film composition. Subsequent to HT, the photoconductivity spectrum considerably
widens and appears the impurity maximums at 2=0.58 0.69 m and 3=0.95 1.05 m.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34894
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Lubuna, Beegum Shafeek. "Organic-Inorganic Hetero Junction White Light Emitting Diode : N-type ZnO and P-type conjugated polymer." Thesis, Linköping University, Department of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11195.
Full textAbstract:
<p>The purpose of this thesis work is to design and fabricates organic-inorganic hetero junction White Light Emitting Diode (WLED). In this WLED, inorganic material is n- type ZnO and organic material is p-type conjugated polymer. The first task was to synthesise vertically aligned ZnO nano-rods on glass as well as on plastic substrates using aqueous chemical growth method at a low temperature. The second task was to find out the proper p- type organic material that gives cheap and high efficient WLED operation. The proposed polymer shouldn’t create a high barrier potential across the interface and also it should block electrons entering into the polymer. To optimize the efficiency of WLED; charge injection, charge transport and charge recombination must be considered. The hetero junction organic-inorganic structures have to be engineered very carefully in order to obtain the desired light emission. The layered structure is composed of p-polymer/n-ZnO and the recombination has been desired to occur at the ZnO layer in order to obtain white light emission. Electrical characterization of the devices was carried out to test the rectifying properties of the hetero junction diodes.</p><p>iv</p>
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Raissi, Farshid. "Long Josephson junctions as duals of p-n junctions." 1991. http://catalog.hathitrust.org/api/volumes/oclc/25330269.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1991.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 72-73).
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WU, XIE-LIN, and 吳協霖. "The characteristics of polysilicon P-N junctions." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/05482516643053820750.
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Mahajan, Sonia. "Study Of Transport Behaviour Of P-GaAs/N-GaAs EPI-Junctions." Thesis, 1999. http://etd.iisc.ernet.in/handle/2005/1671.
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Yang, Cheng-Jer, and 楊正杰. "Study of the Characteristics of Nickel Silicided P+N Shallow Junctions." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/04656653372667921631.
Full textAbstract:
碩士<br>國立交通大學<br>電子工程學系<br>85<br>To minimize the short channel effect and reduce the contact
resistance of the source/drain and electroded as well as
interconnections, metal silicides have been used to apply in
very-large-scale-integration(VLSI) for improving submicrometer
devices and circuit performance. In thesis, nickel silicide
would be a proper material because of the wide temperature
process window, good resistance to lateral growth between the
gate and the source/drain, and less silicon consumtion during
silicidation. Moreover, various techniques have been used to
form silicided shallow junctions. The first method to make
silicided shallow junctions is to deposit a layer of metal and
then implant dopants through the metal layer(ITM). The following
technique is using the nickel silicide as implantation barrier.
To achieve the shallow junctions and low reverse leakage
current, it is severe preventing boron peneration during
silicidation. A method which is proposed is to deposit a layer
of amorphous silicon(a-Si) and then implant dopants through the
a-Si layer. The boron channeling is effectively elimenated by
the ITA scheme. Another novel structure which is proposed to
deposit a metal layer on the amorphous silicon layer and then
implant dopants through the metal/Si(ITMA). In this thesis, the
high temperature thermal stability of the nickel silicide and
the electrical characteristics of p+n junctions have also been
investigated.
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Chung, Ting-Tse, and 鍾定澤. "Characterization of ZnO:Sb/ZnO p-n junctions grown by pulsed-laser deposition." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/rwa353.
Full textAbstract:
碩士<br>國立臺北科技大學<br>光電工程系研究所<br>100<br>In this study, Sb-doped ZnO films are used for the p-type sides and intrinsic ZnO films for the n-type sides of p-n junctions grown by pulsed-laser deposition. ZnO films have been deposited on (002) sapphire substrates in an ambient gas of oxygen to reduce oxygen vacancies. P-type ZnO:Sb films have been cooled in nitrogen ambient to raise the hole concentration.
We found another procedure which can removal the schottky effect in p-type ZnO:Sb films during the current-to-voltage (I-V) measurement. And distinct rectifying I-V characteristics are observed for junctions between ZnO and p-type ZnO:Sb films , exhibiting a threshold voltage of 0.8 V and reverse-bias leakage current was 0.1 uA . The X-ray diffraction shows that ZnO films are highly orientated along the (002) direction. Hall measurement indicated that the hole concentration was raised into high order of 1018cm-3 after cooled procedure. The optical transmission of the p–n junction sample was 60~80% in the visible region.
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HUNG, CHENG-WEI, and 黃承尉. "Study of ZnO Thin Film P-N Junctions Fabricated on Glass Substrates." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/bqrdbr.
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碩士<br>大葉大學<br>電機工程學系<br>105<br>In this study, we study the p-n junction which made based on the magnetron sputtering with the nitrogen as reaction gas, to grow ZnO thin films on glass substrate (Corning Eagle 2000). The first stage of this study is to grow p-type ZnO thin films with nitrogen doped. The total pressure of working gas is 150 mtorr. The working gas and the reaction gas are Ar and N2, respectively. The percentage of the N2 is 10% and 15% of the total working gas pressure. The thin films growing temperature is setting at 300 ℃ or 400 ℃. The deposited ZnO:N thin films were analyzed by XRD and found out that the thin films were epitaxial with c-axis perpendicular to the substrates. The resistivity, carrier concentration and carrier mobility of thedeposited thin films were measured by a Hall measurement system. The Hall coefficient of ZnO:N thin films which grow with 15 % of the reaction gas at 400 ℃ was positive, which indicated that thin films is p-type.
At the second stage, we use the ZnO thin films which deposited under the condition of the results of the first stage. Combine with photo lithography and wet etching to pattern the p-n junction. The junctions were measured by the semiconductor characteristics measuring instrument to explore the characteristics.
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Madishetty, Sridhar. "Formation and characterization of n/p shallow junctions in sub-micron MOSFETs." Thesis, 2002. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2002-064.
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Thesis (M.S.) -- New Jersey Institute of Technology, Committee for the Interdisciplinary Program in Materials Science and Engineering, 2002.<br>Includes bibliographical references. Also available via the World Wide Web.
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Chawda, Samrat G. "Formation & characterization of p/n shallow junctions in sub-micron MOSFETs." Thesis, 2002. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2002-060.
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Thesis (M.S.) -- New Jersey Institute of Technology, Committee for the Interdisciplinary Program in Materials Science and Engineering, 2002.<br>Includes bibliographical references. Also available via the World Wide Web.
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Krishna, Heera. "Phosphorus(III) Ligands Based On The P-N-P Skeleton And Their Transition Metal Complexes." Thesis, 2007. http://hdl.handle.net/2005/526.
Full textAbstract:
There is considerable current interest in the design and synthesis of new phosphorus ligands and their transition metal complexes in view of their potential applications in homogeneous catalysis. The present study is concerned with the synthesis of new chiral and achiral “ diphosphazanes”, which constitute a class of versatile short-bite bidentate phosphine ligands, and studying their reactivity towards late transition metals (Ag, Pd and Ru). Symmetrical diphosphazane ligands, MeN{P(OR)2}2 (R = (1R, 2S, 5R)-menthyl) and MeN{P(SR)2}2, (R = C6H5) and unsymmetrical diphosphazane ligands, Ph2PN(Pri)PPhY, (Y =OC6H3Me2-2,6 or NMePh) have been synthesized and structurally characterized. The reactivity of these ligands towards the transition metal precursors viz., [PdCl2(COD)] and [CpRu(PPh3)2Cl] has been investigated.
The reaction of [Ru(bipy)2Cl2] with the diphosphazane, PriN(PPh2)2 in the presence of AgOTf to synthesize [Ru(bipy)2{PriN(PPh2)2}2]OTf led to an unexpected entry into the Ag(I) chemistry of this ligand. By optimizing the reaction conditions, several mononuclear, dinuclear and trinuclear complexes such as [Ag(K2-PriN(PPh2)2)2]X, [Ag(µ-PriN(PPh2)2)X]2 and [Ag3(µ-(Cl)2(µ-PriN(PPh2)2)3]X (X = NO3, OTf or PF6) have been synthesized. A polymeric complex, [Ag2(µ-PriN(PPh2)2)( µ-NO3)2]n in which the ligand adopts a unique ‘Cs’ geometry has also beenstructurally characterized. This polymeric complex is used to synthesize a helical polymer,[Ag2{µ-PriN(PPh2)2}(DABCO)(NO3)2]n and π- π stacked supramolecular assemblies such as
[Ag2(NO3)2(µ-Ph2PN(Pri)PPh2)(2,2'-bipy)2] and [Ag2{µ-PriN(PPh2)2}(1,10-phen)2](NO3)2].
The reaction of a sterically bulky diphosphazane ligand, EtN{P(OC6H3(Pri)2-2,6)2}2 (L) with[(η3-1-R,R’-C3H3)Pd(µ-Cl)]2 in the presence of NH4PF6 gives the cationic complex, [(η 3-1-R,R’-C3H3)Pd(L)]PF6 (R = H; R’= H or Me) as the sole product. In the absence of NH4PF6, theinitially formed cationic complex, [(η 3-C3H5)Pd(L)]PF6 is transformed into a mixture of chlorobridged complexes over a period of 96 h. An octa-palladium complex [(η3-C3H5)(2-Cl- η3-C3H4)Pd4(µ-Cl)4(µ-L)]2 is formed as a result of nucleophilic substitution by a chloride ligand at the central allyl carbon atom. The reaction of L with [(η3-C3H5)Pd(µ-Cl)]2 in the presence of K2CO3 yields a dinuclear complex, [(η3-C3H5)Pd2(µ-L)Cl] containing a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and large“turn-over numbers” in the catalytic hydrophenylation of norbornene.
Reactions of diphosphazanes with cyclometalated palladium complexes of the general formula
[Pd( k2-(C,N)-Me2NCHMe(C6H4))(solvent)2]PF6 derived from a chiral amine, (S)-N,N-dimethyl-1-phenethylamine give chelate complexes of the type [Pd{ k2-(C,N)-Me2NCHMe(C6H4)}(LL)] PF6, (L-L = diphosphazane). Chiral racemic diphosphazanes give a mixture of diastereomeric(S,R and S,S) complexes which could not be separated. These cyclometalated complexes show moderate catalytic activity in C−C bond forming reactions (hydrophenylation /Suzuki coupling).
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Liang, Jingwei, and 梁耕維. "The Study On The Preparation Doped CuInO2 Films And The P/N Junctions." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/40282243390004451968.
Full textAbstract:
碩士<br>義守大學<br>材料科學與工程學系<br>100<br>In this study we used the RF magnetron sputtering method to deposit CuInO2 films on the (0001) sapphire substrates. The temperature and atmosphere of deposition, as well as the temperature and atmosphere of annealing were changed to find out their best physical properties. Meanwhile, the doping of Sr and Sn atoms was employed to ameliorate the properties of resistivity and transmittance. For as-deposited thin films, the best deposition condition with high transmittance and crystallization occurred when the temperature was 500℃ and the atmospheric ratio of argon and oxygen was 5:5.
For air-annealed thin films, the best condition including the visible light transmittance of 91%, energy gap of 3.5eV, and resistivity of 3.72(Ω．cm) appeared when the annealing temperature was 950 ℃. For annealed thin films in oxygen atmosphere, the best condition that included the excellent crystallization, the strongest (006) preferred orientation, visible light transmittance of 85%, energy gap of 3.7eV, and resistivity of 1.9× 10-1Ω.cm happened at annealing time of 30 min under temperature of 950 ℃.
The doping of Sn atoms changed the thin films from p-type to n-type. For the thin film with 7at% of Sn doping, the resistivity was 7.3 × 10-1Ω.cm. When the Sn doping concentration was 5at%, the visible light transmittance was up to 90% and the energy gap was 3.8eV.
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Qiu, Ming-Jie, and 邱明杰. "The study of Deep Levels in Pd and Pt Doped Si P-N Junctions." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/44181085466842886237.
Full textAbstract:
碩士<br>國立交通大學<br>電子研究所<br>84<br>In this thesis, the characteristics of palladium-doped and
platinum-doped silicon diodes are studied for the fabrication
of the fast switching diodes. The goal of this study is to
obtain higher trap concentration to reduce the switching time
in diodes. Deep level transient spectroscopy(DLTS)is employed
to analyze the electric deep levels and the trap concentration.
The effect of the diffusion temperature and the diffustion
durationn on theconcentrations of deep levels are studies.It is
found that the concentration of deep levels due to Pd or Pt
diffusion increases with increasing and duration.In
addition, the measured switching time for Pd and Pt decreases
with increasing temperature and duration.Furthermore,the leakage
current of diodes is proportional to the trap concentration
for both palladium and platinum.
Finally,the deep energy levels are observed.For palladium,a
donor level and an acceptor level are located at Ev+0.52eV
and Ec-0.22eV,respectively. For platinum,a donor level and an
acceptor level are located at Ev+0.28eV and Ec-0.2eV,
respectively.
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范介寧. "Process investigation and analysis of Si nanowire solar cells with radial p-n junctions." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/82927078169471496127.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>光電科學研究所<br>99<br>In this thesis, we successfully accomplished silicon nanowire solar cells with radial p-n junctions on the electroless etched nanowires, and evidenced the existence of the radial junctions using a conductive atomic force microscope. Effects of various processing parameters, such as length of the nanowires, KOH treatment, and backside laser annealing were studied. Currently, the attained best conversion efficiency of nanowire solar cells with radial junctions gave 11.49%; and, there is still room for improvement. Employing a low-cost home-made non-toxic dopant source, passivated by theTEOS in the prepared dopant source, with the inherent anti-reflection of the nanowires, the radial junction nanowire solar cell was easily prepared within very short time through the help of rapid thermal annealing. Moreover, the radial junctions incorporate both good light absorption and carrier collection, which further makes the quality requirement for silicon substrates less stringent. We also found that the conversion efficiencies of the nanowire solar cells would be hampered in case the length of nanowires exceeded 500nm. In our last experiment, we employed CO2 laser heating on the backside of the solar cells for possible back surface field formation and found that the Voc’s and Isc’s of the solar cell would all be improved after laser heating.
We believe that the proposed techniques can help further cost-reduction of solar cells, which opens a good chance to break through the current bottle neck of widespread photovoltaic use.
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HUANG, LI-MING, and 黃立銘. "Study of the electrical characteristics of P/N junctions without and with cobalt silicide contacts." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/72339107520682602497.
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Chou, Shih-Min, and 周仕旻. "Growth Characteristics of Doped ZnO Transparent Conducting Films and the Fabrication of p-n Homo/Hetero-junctions." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/03610904533562080805.
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博士<br>國立成功大學<br>材料科學及工程學系碩博士班<br>97<br>Due to the low resistivity and high transmittance in visible spectrum, transparent conducting films are comprehensively applied in optoelectronics. Among them, ZnO is easily etched in process and the electrical properties can be further improved by donor doping as well as the abundance of Zn, making ZnO-based films more potential. Besides, the fabrication of ZnO-based homojunction using p-type ZnO films indicates the extensive applications of ZnO. In addition, the recent research of ZnO/Cu2O heterojunctions in solar cells also attracts many interesting attentions.
In this study, 2wt%Al2O3-ZnO is used as target to deposit transparent conducting films by RF magnetron sputtering system. Three issues investigated in this study are (1) the effects of deposition and annealing parameters on the structural, electrical and optical properties of ZnO:Al films as well as the applications of ZnO:Al films in the ethanol gas sensor detection; (2) the fabrication of p-type Al-N co-doped ZnO films by different N2O/(N2O+Ar) volume ratios and the effects of annealing condition on the structural, electrical and optical properties of Al-N co-doped ZnO; (3) the effects of deposition parameters on the structural and photovoltaic properties of ZnO:Al/Cu2O heterojunctions for (200) and (111)-orientation Cu2O.
From the results, the ZnO:Al film grows with the preferred (0002) plane and its deposition rate increases as the RF power increases. After the substrate heating and post-deposition annealing, the grain growth is observed and (0002) diffraction peak shifts to high 2θ position, indicating the relaxation of residual stress in the films. As the RF power used is 120 W, the ZnO:Al film has a low resistivity that can further be reduced with the substrate heating at 250℃. After annealing at 500℃ in H2 for 1 hr, the lowest resistivity of 5.15×10-4 Ω•cm is obtained with the electron concentration and mobility of 8.03×1020 cm-3 and 15.1 cm2V-1s-1, respectively. For various RF powers and substrate temperatures, the transmittance of ZnO:Al films is higher than 90% in average during the visible spectrum. After annealing in O2, the absorption edge has a red-shift; however, it has a blue shift for annealing in H2. For the application as a ethanol gas sensor, ZnO:Al films have a quick response-recovery characteristics and the sensitivity is about 20 with the ethanol concentration of 400 ppm at the operating temperature of 250℃.
For the fabrication of p-type Al-N co-doped ZnO films, the deposition rate decreases as the N2O/(N2O+Ar) volume ratio increases. At the same time, the (0002) diffraction peak broadens but decreases in intensity, indicating the degradation of the thin-film crystallinity. As the volume ratio increases to 20%, the conduction type turns from n type to p type. With the ratio of 30%, p-type Al-N co-doped ZnO film has a low resistivity of 2.57 Ω•cm with the hole concentration and mobility of 2.53×1017 cm-3及9.6 cm2V-1s-1, respectively. When the ratio is larger than 60%, the conduction type returns to n type. For various N2O volume ratios, the transmittance of Al-N co-doped ZnO films is higher than 85% and the absorption edge shows a red-shift with the introduction of N2O.
Using (111)-orientated Cu2O films as substrates for the fabrication of ZnO:Al/Cu2O heterojunctions, the ZnO:Al films deposited on Cu2O films with or without substrate heating show a preferred (0002) due to the small lattice mismatch. For (200)-orientated Cu2O films, substrate heating is helpful for the growth of ZnO:Al films with a preferred (0002). Under the illumination condition of 83.2 mW/cm2, the conversion efficiency of ZnO:Al/(111)-orientated Cu2O heterojunction is higher than that of ZnO:Al/(200)-orientated Cu2O heterojunction. With an appropriate modification of thickness, ZnO:Al(200 nm)/(111)-orientated Cu2O(1 μm) heterojunction has the best conversion efficiency of 0.22% in this study with the open-circuit voltage of 0.15 V, short-circuit current density of 4.3 mA/cm2 and fill-factor of 0.29.
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Kao, Hung-Yi, and 高宏易. "The influence of the modulation efficiency in scanning capacitance microscopy on the observation of p-n junctions." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/m4saa8.
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碩士<br>國立中興大學<br>物理學系所<br>106<br>With voltage modulation technology, scanning capacitance microscopy (SCM) is a metrology method analyzing electrical properties of semiconductor materials. SCM is extremely sensitive to capacitance variation and capable of electrical analyses of electronic devices and materials, such as observing p-n junctions and two-dimensional carrier distributions in semiconductors, as well as measuring the junction depth and effective channel length in electronic devices. Modulation efficiency (ME) is an important indicator of the signal detection in SCM. Combining the ME with the principle of signal balance at p-n junctions, one can establish the relation between the ME and the change in total capacitance, being helpful for discussing the influence of the ME on the observation of p-n junction depths. In this thesis, I discussed the influence of the carrier concentration distribution, the preparation processes of the surface oxide layer and the specimen contact electrode on the ME by increasing the modulation area. The modulation-voltage-induced junction shifts were also studied. Experimental results showed that the ME varied with carrier concentration in modulated area due to the non-monotonic behavior of the SCM signals. Therefore, the junction depth increased with the modulated area and hence shifted toward the area with a lower ME. With the same oxidation process, the surface oxide layer resulted in different oxidation rates for p-type and n-type specimens, leading to different ME values in p-type and n-type regions. For different electrodes contacting with a silicon substrate, the work function difference between the contact electrode and the silicon substrate leaded to different ME for p-type and n-type regions. According to the discussion on the factors influencing the ME, the importance of the ME to the observations and the measurements of p-n junctions was revealed.
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Liao, Hsiu-Hsien, and 廖修賢. "Studies of N+-P Junctions on Ultrathin GeSn/Ge Structure and Self-Aligned Contact Resistance Test Structure." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2urh6a.
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碩士<br>國立交通大學<br>電子研究所<br>107<br>In this thesis, we thoroughly studied N+-P junctions on ultrathin GeSn/Ge structure and successfully developed a novel contact resistance test structure, aimed for source/drain application in modern Si/Ge-based FETs.
First, well-behaved N+-P junctions possessing high forward bias current density of 250 A/cm2 at −1 V and high On/Off ratio over 3×104 were realized on ultrathin GeSn/Ge Structure using P ion implantation and low-temperature thermal annealing. Also, various electrical characteristic analyses were carried out to investigate the leakage characteristic of these junctions.
Moreover, by performing thermal annealing at different temperatures, we gain an overall insight into the effect of activation temperatures on junction leakage. It is found that the leakage current remains low when samples were annealed at a temperature range of 400oC to 500oC. But, the leakage current of junctions increases drastically when annealing temperatures exceed 550oC. A model is then proposed on the basis of the results of advanced electrical and material characterization to explain ascending junction leakage: A large numbers of defects induced by high-dose ion implantation intermix with Sn atoms escaping from original lattice site. As a result of enhanced Sn diffusion via vacancy-mediated mechanism, Sn atoms come closer to the metallurgical junction of N+-P diode after a high-temperature annealing. These Sn atoms then serve as effective generation-recombination centers in the space-charge region of junction devices. Besides, the effects of activation temperatures and contact interfaces on contact resistance and sheet resistance of Ni/GeSn is preliminarily explored. We observed that all the samples exhibit similar contact characteristics.
On the other hand, a novel test structure called self-aligned TLM (SATLM) was designed and fabricated. By realizing self-aligned contact window definition, the robustness of TLM structure towards lateral current spreading effect and nanoscale contact patterning issues can be greatly improved. Using proposed test structure, we demonstrate significant ρ_c extraction of 4.7×10−8 Ω-cm2 for Ti/Si:P contact. In addition, the influence of post-metal annealing temperatures and contact width on extraction results was discussed. Finally, the extraction results of SATLM were verified and compared with that of CBKR structure fabricated under the identical fabrication processes. The proposed structure is thus confirmed to be less vulnerable to the parasitic elements which limit the measurement accuracy.
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Chen, Yung-Kuang, and 陳永光. "The influence of the contact electrode in scanning capacitance microscopy on the observation of p-n junctions." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5759005%22.&searchmode=basic.
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碩士<br>國立中興大學<br>奈米科學研究所<br>107<br>S Scanning capacitance microscopy (SCM) is a characterization method that uses modulation voltage to measure the change in capacitance of semiconductor materials. SCM is also for reliability and failure analyses of semiconductor processes and can be used to observe two-dimensional carrier concentration distributions, effective channel lengths, and p-n junctions of semiconductor devices and materials.
Basing on the relation between the modulation efficiency and the signal balance rule at a p-n junction, the factors affecting the depth of a p-n junction were discussed in depth in this article in order to find a contact electrode more suitable for observing p-n junctions and improving the reliability of SCM analysis. By studying the influence of the surface oxide layer, the back-contact electrode, the electrode material, and the conductive probe, on observing a p-n junction, I investigated the factors leading to observed junction-depth shift induced by the modulated voltage. With increasing the modulated voltage in SCM, the observed junction-depth shifted toward the region with low modulation efficiency. Experimental results showed that the surface oxide quality alters junction depth measurements. The back-contact electrode setup also affected the observed junction depth. In addition, the electrode materials for the back-contact electrode and the conductive probe were another dominant factors influencing the observation of p-n junctions and junction depth measurements. Eliminating the above factors affecting the SCM analyses of p-n junctions, the reliability of SCM measurements on p-n junctions can be enhanced.
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Ramirez, Caballero Gustavo. "Nanoscale Confinement Effects between Thin Metallic Surfaces: Fundamentals and Potential Applications." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10506.
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Density functional theory is used to study the physico-chemical effects of two metallic thin films separated by distances in a range of 4-10 amperes. In this condition, the electrons from the metallic thin film surfaces tunnel through the energy barrier existing between the separated thin films, creating an electronic distribution in the gap between films. The characteristics and features of this electronic distribution, such as energy, momentum, and number of electrons, can be traced by quantum mechanical analyses. These same features can be tuned by varying metallic thin film properties like thickness, separation between films, and film chemical nature. The possibility to tune the physical properties of the electrons located in the gap between thin films makes the studied systems promising for applications that range from catalysis to nano-electronics.
Molecular oxygen, water, and ethylene were located in the gap between thin films in order to study the physical and chemical effects of having those molecules in the gap between thin films. It was observed that the electron structure in the gap modifies the geometric and electronic structure of those molecules placed in the gap. In the case of molecular oxygen, it was found that the dissociation energy can be tuned by changing the separation between thin films and changing the chemical nature of the surface and overlayer of the thin film. For water, it was found that by tuning the chemical nature of the surface and sub-surface of both metallic thin films, molecular water dissociation can occur. When ethylene was located in the gap between Ti/Pt thin films, the molecule converts in an anion radical adopting the geometry and structure of the activated monomer necessary to initiate chain polymerization.
Regarding magnetism, it was found that by the surface interaction between Ti/Pt and Pt thin films, the magnetic moment of the system decreases as the separation between thin films decreases. The phenomenon was explained by changes observed in the number of electronic states at the Fermi level and in the exchange splitting as a function of separation between films. Finally, a system that resembles a p-n junction was proposed and analyzed. The system is a junction of two metallic thin films with different electronic density in the gap between surfaces. These junctions can be the building blocks for many electronic devices.
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Chen, Lee-Fong, and 陳立峰. "Fabrication of transparent CuCrO2:Mg/ZnO p-n junctions diode prepared by RF sputtering on ITO glass substrate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/82813580241707346869.
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碩士<br>大同大學<br>光電工程研究所<br>100<br>This study investigated the characteristics of CuCrO2: Mg and ZnO diodes under the different process parameters. Fabrication of transparent CuCrO2:Mg/ZnO p-n junctions diode prepared by RF sputtering on ITO glass substrat. Improving the substrate temperature, the process pressure, thickness of film, and the proportion of oxygen and argon can be transparent p-n junction diode. The structural properties of CuCrO2:Mg and ZnO thin film was investigated by X-ray diffraction (XRD). The morphologies and the film thickness was investigated by scanning electron microscope (SEM). Atomic force microscopy (AFM) shows that the surface roughness is about 11.87 nm. By UV–visible spectroscopy the device exhibited an optical transparency of 75% in the visible region and the energy gap is about 3.19 eV. The I–V characteristics were measured by semiconductor characterization system. Applied voltage ± 4V, the device deposited at 450 °C shows great forward current ratio 85.91, which also demonstrate that it can apply in heterojunction device.
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Cheng, Shan-Yun, and 鄭善允. "Effects of short-period superlattice buffer on the low-frequency noise of photovoltage for GaN/InGaN P-N junctions." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/03040627391970246999.
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碩士<br>國立中興大學<br>精密工程學系所<br>96<br>Abstract
In recent years, the trend of developing new energy resources, solar cell and light emitting diode becomes a popular area in research. The solar cell gives a new source of energy, the light emitting diode saves energy for lighting and many other photonic devices provide variety of service for our daily life. The noise behavior of these systems devices is a very important topic while being applied to real systems.
This thesis is about the effect of short-period superlattice (SPSL) in GaN/InGaN P-N junction structures on noise of photo voltage. We used three kinds of samples in this study: samples with a SPSL layer, samples with two buffer layers, and samples with three SPSL layers. Under same forward bias voltage, samples with two buffer layers has the largest current(85mA at 4V) and also luminescence efficiency.Samples with three buffer layers has a larger defect density than that of other samples due to the strain relaxation problem. We measured the noise spectrum of these samples under different photo-voltage bias. The photovoltage of these samples shows an enhanced 1/f noise, whose magnitude increases with the power of illumination. According to our experiment data,the samples with one buffer layer has the lowest noise, while samples with two buffer layers has the second lowest noise and samples with three buffer layers has the highest noise. Even though the defects density and noise behavior do not match completely, our results do suggest that higher dislocation density causes higher noise level.
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Kang, Inkuk. "Formation of N⁺P junctions using in-situ phosphorus doped selective Si1-xGex alloys for CMOS technology nodes beyond 50nm." 2004. http://www.lib.ncsu.edu/theses/available/etd-03312004-172745/unrestricted/etd.pdf.
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Liu, Jing. "Germanosilicide contacts to ultra-shallow p⁺n junctions of nanoscale CMOS integrated circuits by selective deposition of in-situ doped silicon-germanium alloys." 2003. http://www.lib.ncsu.edu/theses/available/etd-04192003-163310/unrestricted/etd.pdf.
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