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1
Meyer, J. R., C. A. Hoffman, J. Antoszewski, and L. Faraone. "Quantitative mobility spectrum analysis of multicarrier conduction in semiconductors." Journal of Applied Physics 81, no. 2 (January 15, 1997): 709–13. http://dx.doi.org/10.1063/1.364211.
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Lee, Hong-Sub, and Hyung-Ho Park. "Band Structure Analysis of La0.7Sr0.3MnO3Perovskite Manganite Using a Synchrotron." Advances in Condensed Matter Physics 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/746475.
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Oxide semiconductors and their application in next-generation devices have received a great deal of attention due to their various optical, electric, and magnetic properties. For various applications, an understanding of these properties and their mechanisms is also very important. Various characteristics of these oxides originate from the band structure. In this study, we introduce a band structure analysis technique using a soft X-ray energy source to study aLa0.7Sr0.3MnO3(LSMO) oxide semiconductor. The band structure is formed by a valence band, conduction band, band gap, work function, and electron affinity. These can be determined from secondary electron cut-off, valence band spectrum, O 1s core electron, and O K-edge measurements using synchrotron radiation. A detailed analysis of the band structure of the LSMO perovskite manganite oxide semiconductor thin film was established using these techniques.
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Kobasa, I. M. "Heterostructures based on nanodispersed TiO2 and binary systems TiO2-CdTe, TiO2-Cu(In,Ga)Se2 sensitized by polymethyn dye, as photocatalysts of redox processes." Chernivtsi University Scientific Herald. Chemistry, no. 819 (2019): 23–30. http://dx.doi.org/10.31861/chem-2019-819-04.
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New light-sensitive heterostructures of semiconductors (TiO2, TiO2-CdTe, TiO2-Cu(In,Ga)Se2) sensitized with an anionic polymethine dye with three conjugated chromophores have been developed. Based on the analysis of the results of spectral, electrochemical and energy characteristics of the studied dye, the possibility of its use as an effective sensitizer of these semiconductor materials is shown. It was found that the deposition of the dye on TiO2 leads to both batochromic and hypsochromic shifts of long wavelength absorption bands, the values of which depend on the dye content in the heterostructure. This leads to a redistribution of the intensities of the absorption bands, they expand and cover almost the entire part of the visible and near-IR regions of the spectrum. This feature of the created heterostructure allows to increase the efficiency of their photocatalytic action through the use of light quanta of a wide energy range. The results of the analysis of the absorption spectra of heterostructures testify to the significant influence of semiconductors on the electronic system of dye molecules. As a result, the angle between the directions of the chromophores changes. The antibate dependence of the degree of conformational changes on the amount of dye in the heterostructure is revealed. This indicates a decrease in the interaction with the semiconductor with increasing concentration and explains the decrease in the photocatalytic activity of heterostructures at a significant content of sensitizer. Using the method of cyclic voltammetry, for the first time the oxidation and reduction potentials of the investigated polymethine dye were determined. The values of HOMO and LUMO energy levels are calculated, a forecast is made regarding the possibility of their use as sensitizers of the studied semiconductors and the creation of highly efficient redox systems. The photocatalytic activity of heterostructures in the reactions of reduction of methylene blue and oxidation of iodide ions under irradiation with light absorbed by a semiconductor and a sensitizer has been revealed. Based on the analysis of energy parameters of electronic processes, the scheme of this photocatalytic transformation is proposed and substantiated.
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Kundmann, Michael K., and Gronsky Ronald. "Plasmon lineshape analysis in EELS of semiconductors." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 500–501. http://dx.doi.org/10.1017/s042482010010456x.
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Many materials display plasmon peaks in their low-loss EELS spectra. The plasmon peak shape, energy, and linewidth are characteristic of each material and are sensitive to the outer-shell electron density and details of the electronic band and energy-level structures. As these properties are a function not only of the composition but also the structure and chemistry of a sample, plasmon spectroscopy can potentially become a materials characterization tool which goes beyond the elemental analyses provided by EDXS and ionization-edge EELS. However, analysis of plasmon spectra requires considerably more sophistication than either of the aforementioned techniques due to the possibility of overlapping spectrum features, the prevalence of plural scattering, and the difficulty in detecting and characterizing the often subtle differences between the plasmon spectra of similar materials. As yet, no systematic approach to plasmon analysis analogous to that available commercially for EDXS or EELS core-edge analysis has been developed. We present here an approach which, for the simple case of semiconductors, makes some progress in this direction.
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García, Gregorio, Pablo Sánchez-Palencia, Pablo Palacios, and Perla Wahnón. "Transition Metal-Hyperdoped InP Semiconductors as Efficient Solar Absorber Materials." Nanomaterials 10, no. 2 (February 7, 2020): 283. http://dx.doi.org/10.3390/nano10020283.
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This work explores the possibility of increasing the photovoltaic efficiency of InP semiconductors through a hyperdoping process with transition metals (TM = Ti, V, Cr, Mn). To this end, we investigated the crystal structure, electronic band and optical absorption features of TM-hyperdoped InP (TM@InP), with the formula TMxIn1-xP (x = 0.03), by using accurate ab initio electronic structure calculations. The analysis of the electronic structure shows that TM 3d-orbitals induce new states in the host semiconductor bandgap, leading to improved absorption features that cover the whole range of the sunlight spectrum. The best results are obtained for Cr@InP, which is an excellent candidate as an in-gap band (IGB) absorber material. As a result, the sunlight absorption of the material is considerably improved through new sub-bandgap transitions across the IGB. Our results provide a systematic and overall perspective about the effects of transition metal hyperdoping into the exploitation of new semiconductors as potential key materials for photovoltaic applications.
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West, Ryan M., Colby R. Watts, Mira Josowicz, and Jiří Janata. "Fluctuation analysis of work function of organic semiconductors." Collection of Czechoslovak Chemical Communications 76, no. 7 (2011): 843–58. http://dx.doi.org/10.1135/cccc2011055.
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We demonstrate, for the first time, work function fluctuations of a polyaniline film when used as the gate conductor of an insulated-gate field-effect transistor. The work function fluctuations induce drain current fluctuations, which are in excess of the channel noise of the transistor and the Nyquist noise of the polyaniline film. Using the fluctuation-dissipation theorem, it is determined that the fluctuations have a Lorentzian-like spectrum and are thermally activated with an activated energy of ca. 300 meV. The activation energy, as well as the corner frequency and magnitude of the fluctuations, depend on the applied electric field at the polyaniline–insulator interface. These results, along with coherence measurements, suggest that the fluctuations originate near the interface in the space-charge region of polyaniline. This technique provides kinetic and thermodynamic information about the gate conductor, at equilibrium, which cannot be extracted using other techniques that measure work function. Furthermore, by this technique it is possible to distinguish the fluctuations of the work function from the Nyquist noise. This approach should be generally applicable to any semiconducting material used as the gate conductor of a field-effect transistor.
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Pathak, Dinesh, Sanjay Kumar, Sonali Andotra, Jibin Thomas, Navneet Kaur, Praveen Kumar, and Vaneet Kumar. "New tailored organic semiconductors thin films for optoelectronic applications." European Physical Journal Applied Physics 95, no. 1 (July 2021): 10201. http://dx.doi.org/10.1051/epjap/2021210090.
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In this study, we have investigated new tailored organic semiconductor materials for optoelectronic application, such as organic solar cells. The carbon-based organic semiconductor material has promising advantages in organic thin-film form. Moreover, due to its low cost, organic thin films are suitable and cheaper than inorganic thin-film. The bandgap of organic semiconductors materials can be tuned and mostly lies between 2.0 eV and 4 eV and the optical absorption edge of organic semiconductors typically lies in between 1.7 eV and 3 eV. They can be easily tailored by modifying the carbon chain and legends and looks promising for engineering the bandgap to harness the solar spectrum. In this work, with new tailored organic semiconductors, the solution route is explored which is a low-cost processing method. (Anthracen-9-yl) methylene naphthalene-1-amine; 4-(anthracen-9-ylmethyleneamino)-1,5dimethyl-2-phenyl-1H-pyrazol-3-one and N-(anthracen-9-ylmethyl)-3, 4-dimethoxyaniline thin-films are processed by spin coating method with changing concentration such as 0.05 wt.% and 0.08 wt.%. Thin films of organic semiconductors were prepared on the glass substrate and annealed at 55 °C. The structural and optical behavior of (Anthracen-9-yl) methylene naphthalene-1-amine, 4-(anthracen-9-ylmethyleneamino)-1,5dimethyl-2-phenyl-1H-pyrazol-3-one, and N-(anthracen-9-ylmethyl)-3, 4-dimethoxyaniline organic semiconductors thin films is studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and UV-Visible spectroscopy technique. The XRD data of the synthesized sample suggests the nano crystallinity of the organic layers. And, the SEM micrographs show the dense packing when we increase the wt.% 0.05 to 0.08. Additionally, analysis of the optical absorption measurements found that the engineered bandgap of synthesized thin films are 2.18 eV, 2.35 eV, 2.36eV, 2.52eV, and 2.65eV which suggest suitability for applications of optoelectronic devices such as solar cell. Such lightweight, eco-friendly and disposable new carbon-based materials seem to have the potential to replace other traditional hazardous heavy materials for future eco-friendly flat fast electronics.
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Morrison, S. Roy. "1/f Noise from levels in a linear or planar array: Dislocations in metals." Canadian Journal of Physics 71, no. 3-4 (March 1, 1993): 147–51. http://dx.doi.org/10.1139/p93-022.
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This report compares the double-layer noise expected for metal dislocations with the earlier analysis of semiconductor dislocations. In both cases we describe the asymmetric trapping of charge over an electrical double layer at the dislocation. The earlier reports describe how a 1/f spectrum should be observed, in the form of a truncated Lorentzian, if the double-layer voltage shows fluctuations greater than kT/q. This report describes the origin of a double layer at metal dislocations that fulfills the requirements. It shows why, despite the substantial difference in parameters, the noise predicted for metals is of the same magnitude (in terms of the Hooge parameter) as that predicted for semiconductors.
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Song, J. G., Lin Hua, Qiang Shen, Fang Wang, and Lian Meng Zhang. "Synthesis and Characterization of SnO2 Nano-Cystalline for Dye Sensitized Solar Cells." Key Engineering Materials 602-603 (March 2014): 876–79. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.876.
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The study of dye-sensitized solar cells (DSCs) based on nanocrystalline films of high band gap semiconductors is a progressive field of research that is being carried out by scientists in a wide range of laboratories. Of the many semiconductor materials utilized for conversion of solar energy into electricity, SnO2 is a high band gap semiconductor that has been used extensively. However, its efficiency is at a relatively lower level when compared to other semiconductor materials such as TiO2 working under similar circumstances. To improve the conversion efficiency of the DSCs, the SnO2 nanorots photocurrent is prepared via the hydrothermal method, and characterized by XRD, FESEM, BET and Absorption spectrum. Though analysis the results, SnO2 nanocrystalline were successfully synthesized using a hydrothermal method by certainly experimental parameters. The SnO2 nanocrystalline is the rod-shape with length for 100nm and diameter for 5nm as pH=11. the specific surface area is 86.3412m2/g, which lay base for reaching the high conversion efficiency of the DSCs.
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Chen, Jingrun, Jason D. A. Lin, and Thuc-Quyen Nguyen. "Towards a Unified Macroscopic Description of Exciton Diffusion in Organic Semiconductors." Communications in Computational Physics 20, no. 3 (August 31, 2016): 754–72. http://dx.doi.org/10.4208/cicp.050615.010216a.
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AbstractWe study the exciton diffusion in organic semiconductors from a macroscopic viewpoint. In a unified way, we conduct the equivalence analysis between Monte-Carlo method and diffusion equation model for photoluminescence quenching and photocurrent spectrum measurements, in both the presence and the absence of Förster energy transfer effect. Connections of these two models to Stern-Volmer method and exciton-exciton annihilation method are also specified for the photoluminescence quenching measurement.
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Камилов, И. К., М. И. Даунов, Г. М. Гаджиев, and Р. К. Арсланов. "Об особенностях примесного энергетического спектра арсенидов." Физика и техника полупроводников 53, no. 12 (2019): 1614. http://dx.doi.org/10.21883/ftp.2019.12.48612.9126.
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The impurity energy spectrum of non-doped bulk crystals of n-type GaAs, InAs, CdSnAs2, CdGeAs2 and CdTe, ZnO is investigated basing on the findings from the quantitative analysis of baric and temperature dependences of kinetic coefficients. It`s found that in the above-listed semiconductors the deep level donor center corresponds to the intrinsic defect of vacancy in the anion sublattice. The energy level positions relative to conduction band edge and the pressure coefficients of energy gaps between them and corresponded conduction band bottom are determined. The shift of deep donor center energy levels towards the depth of the conduction band is observed with a decrease in the forbidden band width in above-listed semiconductors.
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Glinchuk, K. D., and A. V. Prokhorovich. "Features of determination of shallow-level impurity concentrations in semiconductors from analysis of the exciton luminescence spectrum." Semiconductors 36, no. 5 (May 2002): 487–92. http://dx.doi.org/10.1134/1.1478536.
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Jakhmola, Priyanka R., Garima Agarwal, Prafulla K. Jha, and Satya Prakash Bhatnagar. "Nanorod Formation of Copper Indium (di) Selenide Nanorod Synthesize by Solvothermal Route." Advanced Materials Research 1047 (October 2014): 107–11. http://dx.doi.org/10.4028/www.scientific.net/amr.1047.107.
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The compound belongs to I-III-VI2 group are promising material as an effective light-absorbing materials. Now a day, ternary chalcopyrite semiconductors, especially copper based I-III-VI2 semiconductors have attracted many investigators. They have several desirable features as absorbers in the thin film solar cells. In present work, copper indium (di) selenide have been prepared via solvothermal route. Several methods have been reported to prepare CuInSe2 nanostructures by solution route. In present work, tetragonal chalcopyrite copper indium (di) selenide nanorods has been synthesized by solvothermal method using ethylene diamine as a solvent. Structural analysis had been done by X-ray diffraction (XRD). The surface morphology of the as-grown nanorod has been studied using scanning electron microscopy. The bandgap of as grown nanorods is obtained from UV-Vis spectrum which will applicable to the solar cell devices.
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Matysiak, W., and K. Adamczyk. "The analysis of surface morphology, band gaps and optical properties of PAN/GO thin films." Archives of Materials Science and Engineering 2, no. 101 (February 2, 2020): 49–56. http://dx.doi.org/10.5604/01.3001.0014.1190.
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Purpose: PAN/GO nanocomposites are gaining more and more interest from research and industrial environments. According to theoretical studies and experimental tests, PAN/ GO exhibits excellent properties such as tensile strength, good thermal and electrical conductivity, excellent thermal and tribological properties. Thanks to this property, the composite is considered the ideal successor to the nanocomposites used so far. The PAN/GO nanocomposite has great potential in the filtration, automotive, electrical and photovoltaic industry. Design/methodology/approach: The spin-coating process is used to produce thin layers by centrifuging a liquid substance on flat surfaces. The advantages of the spin- coating process are simplicity and ease with which the process can be carried out. Due to the ability to high spin speeds, high airflow leads to fast drying time, which in turn results in high consistency in both macroscopic and nanometre scales. The spin-coting method is usually the starting point and reference point for most academic and industrial processes that require a thin and uniform coating. The use of spin coating has a wide spectrum. This technique can be used to coat small substrates (from a few square mm) up to the coating of flat displays, e.g. TV sets, which may have a meter or more in diameter. Findings: Among the existing methods for producing thin layers, including physical and chemical methods for gas phase deposition or the self-assembly process, the spin-coating process makes it possible to produce uniform thin nanocomposite layers in an easy and cheap way. Spin coating is usually the starting point and reference point for most academic and industrial processes that require a thin and uniform coating. The advantage of the method is the wide spectrum of use. It is used for coating substrates with everything from photoresists, insulators, organic semiconductors, synthetic metals, nanomaterials, metal precursors and metal oxides, transparent conductive oxides and many other materials. Often, spin coating is used to unravel polymer layers or photoresist on semiconductor substrates. Research limitations/implications: Due to the ongoing research on the potential applications of PAN/GO thin layers, including electronics, automotive and photovoltaics, it is worth trying to optimize the parameters of the spin-coiling process such as rotational speed or duration of the process. It is also worth trying to optimize the concentration of GO in the nanocomposite. Practical implications: Despite mixing the solution with an ultrasonic homogenizer to disperse the nanoparticles, the particles dispersed to form a rough surface. Originality/value: Low-cost, easy to carry out method of producing thin nanocomposite layers, having significant application in laboratory environments.
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Złotnik, Sebastian, Jarosław Wróbel, Jacek Boguski, Małgorzata Nyga, Marek Andrzej Kojdecki, and Jerzy Wróbel. "Facile and Electrically Reliable Electroplated Gold Contacts to p-Type InAsSb Bulk-Like Epilayers." Sensors 21, no. 16 (August 4, 2021): 5272. http://dx.doi.org/10.3390/s21165272.
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Narrow band-gap semiconductors, namely ternary InAsSb alloys, find substantial technological importance for mid-infrared application as photodetectors in medical diagnostics or environmental monitoring. Thus, it is crucial to develop electrical contacts for these materials because they are the fundamental blocks of all semiconductor devices. This study demonstrates that electroplated gold contacts can be considered as a simple and reliable metallization technology for the electrical-response examination of a test structure. Unalloyed electroplated Au contacts to InAsSb exhibit specific contact resistivity even lower than vacuum-deposited standard Ti–Au. Moreover, temperature-dependent transport properties, such as Hall carrier concentration and mobility, show similar trends, with a minor shift in the transition temperature. It can be associated with a difference in metallization technology, mainly the presence of a Ti interlayer in vacuum-deposited contacts. Such a transition may give insight into not only the gentle balance changes between conductivity channels but also an impression of changing the dominance of carrier type from p- to n-type. The magnetotransport experiments assisted with mobility spectrum analysis clearly show that such an interpretation is incorrect. InAsSb layers are strongly p-type dominant, with a clear contribution from valence band carriers observed at the whole analyzed temperature range. Furthermore, the presence of thermally activated band electrons is detected at temperatures higher than 220 K.
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Mohan Rai, Dr Hari. "Effect of Edge Fluorination on Electronic and Transport Properties of Aarmchair Boron Nitride Nanoribbons: A First-Principles Study." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (June 30, 2021): 4230–35. http://dx.doi.org/10.22214/ijraset.2021.36026.
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We have systematically investigated the effect of edge fluorination on structural stability, electronic and transport properties of armchair boron nitride nanoribbons (ABNNRs), using first-principles calculations within the frame work of local spin-density approximation (LSDA). ABNNRs with F-passivation on only edge B atoms, regardless of their width, are found to be half-metallic and energetically most stable. For these ribbons, completely spin polarized charge transport is predicted across the Fermi level as a result of giant spin splitting. Transmission spectrum analysis also confirms the separation of spin-up and spin-down electronic channels. It is revealed that F-passivation of only edge N atoms transforms nonmagnetic bare ribbons into magnetic semiconductors whereas fluorination of both the edges does not affect the electronic and magnetic state of bare ribbons significantly. Predicted Half-metallicity projects these ABNNRs as potential candidates for inorganic spintronic devices.
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Song, Jie Guang, Lin Hua, Qiang Shen, Fang Wang, and Lian Meng Zhang. "Effect of pH Value on the Properties of SnO2 Nano-Cystalline for Dye Sensitized Solar Cells." Key Engineering Materials 633 (November 2014): 273–76. http://dx.doi.org/10.4028/www.scientific.net/kem.633.273.
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The study of dye-sensitized solar cells (DSCs) based on nanocrystalline films of high band gap semiconductors is a progressive field of research that is being carried out by scientists in a wide range of laboratories. To improve the conversion efficiency of the DSCs, the SnO2 nanorots photocurrent is prepared via the hydrothermal method, and characterized by XRD, FESEM, BET and Absorption spectrum. Though analysis the results, the conclusion is shown the pure SnO2 is preparation, the SnO2 nanocrystalline both shows the single phase that SnO2 from the sule solution to kalin solution. The prepared SnO2 nanocrystalline under pH=3 shows the particle-shape crystalline, the surface area of SnO2 nanocrystalline is 86.3412m2/g. The prepared SnO2 nanocrystalline under pH=7 shows the short rod-shape crystalline, the surface area of SnO2 nanocrystalline is 58.3408m2/g. The absorbance of SnO2 nanocrystalline shows the strong absorption in the ultraviolet ray range, the absorbance of synthesized SnO2 nanocrystalline under pH=11 shows the highest value.
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Song, Jie Guang, Lin Hua, Qiang Shen, Fang Wang, and Lian Meng Zhang. "Effect of Controlling Concentration on the Properties of SnO2 Nanocystalline for Dye Sensitized Solar Cells." Advanced Materials Research 1058 (November 2014): 149–52. http://dx.doi.org/10.4028/www.scientific.net/amr.1058.149.
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The study of dye-sensitized solar cells (DSCs) based on nanocrystalline films of high band gap semiconductors is a progressive field of research that is being carried out by scientists in a wide range of laboratories. To improve the conversion efficiency of the DSCs, the SnO2 nanorots photocurrent, the effect of controlling concentration on the properties of SnO2 nanocrystalline were investigated via the hydrothermal method, and characterized by XRD, HRTEM, BET and Absorption spectrum. Though analysis the results, the conclusion is shown the pure SnO2 is preparation, the prepared SnO2 nanocrystalline under 0.05mol/L shows the particle-shape crystalline, the surface area of SnO2 nanocrystalline is 102.1683m2/g. The prepared SnO2 nanocrystalline under 1mol/L the fiber-shape crystalline, the surface area of SnO2 nanocrystalline is 79.7591m2/g. The absorbance of SnO2 nanocrystalline shows the strong absorption in the ultraviolet ray range, the absorbance of synthesized SnO2 nanocrystalline under the concentration of SnCl4 solution for 1mol/L shows the higher value.
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Martin, J. L., J. N. Chapman, W. A. P. Nicholson, C. R. Stanley, and A. H. Kean. "Towards Composition Determination in Compound Semiconductors by High-Angle Annular Dark-Field Imaging." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 174–75. http://dx.doi.org/10.1017/s0424820100179622.
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An analytical technique with high spatial resolution is required to investigate the composition of thin layers in compound semiconductor multilayer specimens. The techniques currently in use in TEM can broadly be divided into those in which element-specific signals are collected (e.g. EDX) and those in which compositional information is inferred from the variation in the position or magnitude of some contrast feature in the image (e.g. the displacement of thickness fringes in a wedge-shaped sample ). In this paper we report on the determination of the atomic fraction of Al, denoted x, in the Alx Ga1-x As/GaAssystem by analysis of high-angle annular dark field (HADF) images. The principal advantage of using an imaging technique is that the required information is contained in the variation of a signal proportional to an elastic scattering or a thermal-diffuse scattering cross-section rather than one related to an inner shell excitation. As the former are generally a few orders of magnitude larger than the latter it is possible to obtain an image from a wide area of specimen in the time that is required to collect an adequate EDX spectrum from a single position. Thus accumulation of the required information is much more rapid. Instances where it is desirable to perform a quantitative assay over a wide area include specimens in which there are graded interfaces where the atomic fraction varies continuously (e.g. to obtain specific light-guiding properties) or specimens which are deposited at elevated temperatures where Ga desorption can lead to significant variations from the expected composition. In both circumstances it is useful to make measurements at several locations in planes perpendicular to the growth direction. This is possible using techniques where cross-sectional specimens are employed but not where the presence of a wedge is essential.
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Song, Jie Guang, Lin Hua, Qiang Shen, Fang Wang, and Lian Meng Zhang. "Influence of Synthesis Conditions on the Properties of SnO2 Nano-Crystalline via Hydrothermal Methods." Advanced Materials Research 1119 (July 2015): 54–57. http://dx.doi.org/10.4028/www.scientific.net/amr.1119.54.
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The study of dye-sensitized solar cells (DSCs) based on nanocrystalline films of high band gap semiconductors is a progressive field of research that is being carried out by scientists in a wide range of laboratories. To improve the conversion efficiency of the DSCs, the SnO2 nanocrystalline is prepared via the hydrothermal methods, and characterized by XRD, TEM, BET and Absorption spectrum. Though analysis the results, the conclusion is shown the pure SnO2 is prepared under a certain condition, such as pH=11, reaction time for 8 days, heat treating temperature at 200°C and 0.05mol/L SnCl4 concentration, the SnO2 nanocrystalline both shows the single phase that SnO2 from the sule solution to kalin solution. The prepared SnO2 nanocrystalline shows the rod shape crystalline, the diameter of rod shape crystalline is about 10nm, the length of rod shape crystalline is about 100nm, the surface area of SnO2 nanocrystalline is 79.7591m2/g. The absorbance of SnO2 nanocrystalline shows the strong absorption in the ultraviolet ray range, the absorbance of synthesized SnO2 nanocrystalline shows the highest value.
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Adroja, Devashibhai T., Y. Muro, Toshiro Takabatake, M. D. Le, H. C. Walker, K. A. McEwen, and Andrew T. Boothroyd. "Inelastic Neutron Scattering Investigations of an Anisotropic Hybridization Gap in the Kondo Insulators: CeT2Al10 (T=Fe, Ru and Os)." Solid State Phenomena 257 (October 2016): 11–25. http://dx.doi.org/10.4028/www.scientific.net/ssp.257.11.
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The recent discovery of topological Kondo insulating behaviour in strongly correlated electron systems has generated considerable interest in Kondo insulators both experimentally and theoretically. The Kondo semiconductors CeT2Al10 (T=Fe, Ru and Os) possessing a c-f hybridization gap have received considerable attention recently because of the unexpected high magnetic ordering temperature of CeRu2Al10 (TN=27 K) and CeOs2Al10 (TN=28.5 K) and the Kondo insulating behaviour observed in the valence fluctuating compound CeFe2Al10 with a paramagnetic ground state down to 50 mK. We are investigating this family of compounds, both in polycrystalline and single crystal form, using inelastic neutron scattering to understand the role of anisotropic c-f hybridization on the spin gap formation as well as on their magnetic properties. We have observed a clear sign of a spin gap in all three compounds from our polycrystalline study as well as the existence of a spin gap above the magnetic ordering temperature in T=Ru and Os. Our inelastic neutron scattering studies on single crystals of CeRu2Al10 and CeOs2Al10 revealed dispersive gapped spin wave excitations below TN. Analysis of the spin wave spectrum reveals the presence of strong anisotropic exchange, along the c-axis (or z-axis) stronger than in the ab-plane. These anisotropic exchange interactions force the magnetic moment to align along the c-axis, competing with the single ion crystal field anisotropy, which prefers moments along the a-axis. In the paramagnetic state (below 50 K) of the Kondo insulator CeFe2Al10, we have also observed dispersive gapped magnetic excitations which transform into quasi-elastic scattering on heating to 100 K. We will discuss the origin of the anisotropic hybridization gap in CeFe2Al10 based on theoretical models of heavy-fermion semiconductors.
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Pereyra, Carlos Javier, Florencia Ferrer, Carmela Gómez, Lucía Campo, Ricardo Enrique Marotti, Francisco Martin, Dietmar Leinen, José Ramos-Barrado, and Enrique Ariel Dalchiele. "Optical absorption enhancement in sensitized ZnO nanorods for solar cells." Matéria (Rio de Janeiro) 20, no. 3 (September 2015): 747–56. http://dx.doi.org/10.1590/s1517-707620150003.0079.
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ABSTRACTThe Optical Properties of ZnO Nanorods (NR) sensitized with different semiconductors in Core-Shell nanostructures were studied, comparing them with those of bare ZnO NR. Experimental measurements of Transmittance and Diffuse Reflectance show an increased light absorption at the solar spectrum and the appearances of new absorption edges (AE). The measurements are compared with numerical simulations based on Bruggeman Effective Medium Approximation. An increased absorption with the sensitizer content is observed. For similar changes in filling fractions, CdTe presents higher changes in absorption than CdS. Shifts in the AE are observed experimentally (e.g. between 2.34 eV and 2.66 eV for CdS). These shifts cannot be assigned to sensitizer content or confinement effects. A similar behaviour is observed for CdTe in which the AE measured by transmittance is between 1.31 eV and 1.36 eV, while the one obtained from Kubelka-Munk analysis of reflectance is, for the same samples, 1.57 eV and 1.49 eV, respectively. Moreover, the split-off AE is also observed at 2.55 eV and 2.28 eV. The observed large red-shifts could be associated with an enhancement of the subbandgap absorption due to an increase in the light free path at the core-shell nanostructure.
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Lai, Chin Wei, Kung Shiuh Lau, and Sharifah Bee Abd Hamid. "Controlled Growth of WO3-Loaded TiO2 Nanotubes for Tandem Solar-Driven Water Splitting Cell." Advanced Materials Research 1109 (June 2015): 243–47. http://dx.doi.org/10.4028/www.scientific.net/amr.1109.243.
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Nowadays, hydrogen production using solar-driven photoelectrochemical (PEC) water splitting has attracted considerable attention since the introduction of TiO2 photoelectrodes. However, TiO2 is not able to split water on its own because the cleavage requires more than 1.4 V or even up to 1.9 V, including the redox potential of water (1.23 V) and unavoidable over-potentials. Many semiconductors have been studied, but only a very few large band gap materials can generate enough photo-voltage to cleave water for a single photoelectrode PEC water splitting cell especially processing under solar illumination. In the present study, development of WO3-loaded TiO2 nanotubes (WTNT) is a possible solution to generate a voltage that is high enough to split the water while absorbing more light (photons) from a greater part of solar spectrum. Furthermore, WTNT offered several advantages over the pure TiO2 photoelectrode, such as excellent chemical and thermal stability, active at room temperature as well as responsive to UV and visible illumination. The paper concludes by presenting the comparison results between unmodified TiO2 and WTNT photoelectrode in term of morphology, phase, elemental analysis, electrical properties, and electrochemical properties for the tandem solar-driven water splitting cell.
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Hao, Qing, Dongchao Xu, and Hongbo Zhao. "Systematic Studies of Periodically Nanoporous Si Films for Thermoelectric Applications." MRS Proceedings 1779 (2015): 27–32. http://dx.doi.org/10.1557/opl.2015.707.
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ABSTRACTAs the major heat carriers in dielectrics and semiconductors, phonons are strongly scattered by boundaries and interfaces at the nanoscale, which can lead to a significantly reduced lattice thermal conductivity kL. In recent years, such phonon size effects have been used to enhance the thermoelectric performance of various nanostructured materials. With dramatically reduced kL and bulk-like electrical properties, high thermoelectric performance has been demonstrated for nanoporous Si films at room temperature. Despite these encouraging results, however, challenges still exist in the theoretical explanation of the observed low kL values. Existing studies mainly attribute the observed low kL to phononic effects and/or amorphous pore edges. These two effects can be separated when the specific heat of the film can be measured along with kL to provide more insight into the phonon dispersion modification. In this work, both the specific heat and k of a suspended nanoporous Si film is extracted from the 3ω measurements. The result is compared to the reported kL values of various porous Si films. The influence of employed phonon mean free path spectrum on the data analysis is discussed.
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Kavitha, V., P. S. Ramesh, and D. Geetha. "Synthesis of Cu Loaded TiO2 Nanoparticles for the Improved Photocatalytic Degradation of Rhodamine B." International Journal of Nanoscience 15, no. 05n06 (October 2016): 1660002. http://dx.doi.org/10.1142/s0219581x16600024.
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Copper doped Titanium dioxide TiO2 nanoparticles were synthesized by sol–gel method using titanium tetraisopropoxide and copper sulfate as precursors. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), Photoluminesce spectroscopy (PL) and atomic force microscopy (AFM). XRD analysis confirms the formation of anatase titanium dioxide and average particle size was 35[Formula: see text]nm. Cu– TiO2 exhibits a shift in the absorption edge toward visible spectrum. The rate of recombination and transfer behavior of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. From SEM spherical shaped nanoparticles was observed. Comparing with pure TiO2 nanoparticles, Cu doped TiO2 photocatalyst exhibited enhanced photocatalytic activity under natural sunlight irradiation in the decomposition of rhodamine B aqueous solution. The maximum 97% of degradation efficiency of Rhodamine B was observed at 0.6% Cu–TiO2 within 180[Formula: see text]min. The photocatalytic efficiency of Rhodamine B of Cu doped TiO2 nanoparticle was higher than the pure TiO2, which could be attributed to the small crystallinity intense light absorption in Sunlight and narrow bandgap energy of Copper.
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Smolniakov, V. I., and I. A. Koltun. "Decomposition Spectrometric Data of Energy Dispersive X-Ray Fluorescence Analysis (EDXRF)." Advances in X-ray Analysis 35, B (1991): 743–48. http://dx.doi.org/10.1154/s0376030800012933.
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AbstractIt is well-known that in EDXRF, using high-resolution semiconductor detectors, evaluation of x-ray fluorescence radiation line intensities from multiplex spectrometric information represents definite difficulties, especially in automation of measurement-calculation procedures.A common spectrum decomposition problem is to get the following parameters: a number of spectral lines and their centroids, intensities from measured experimental data and their errors.We have developed special software for solving this problem using personal computers and high-level programming language C. It uses profiles of real-form lines of pure chemical elements produced by semiconductor detector spectrometers and these techniques: digital filters with parameters for suppression of background, multiplex structure analysis, and stable linear least-squares fit to get peak intensities. Also it established special criteria for reliability of the results.We compared our investigation with software “EDXRF” (ver.1.32) arid spectrum decomposition with Gaussian peaks.
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Sergeev, V. А., and S. Е. Reschikoff. "Adaptive algorithms for measuring low-frequency noise parameters of semiconductor devices under mass control." Izmeritel`naya Tekhnika, no. 11 (2020): 59–64. http://dx.doi.org/10.32446/0368-1025it.2020-11-59-64.
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The solution of the problem of increasing the confidence and efficiency of quality control of semiconductor devices is considered. The analysis of conditions for measuring the power spectral density of low – frequency noise of semiconductor devices with a spectrum of the form (γ – the spectrum shape indicator) under mass quality control is presented. The error in measuring the power spectral density under the specified measurement conditions strongly depends on the value of the spectrum shape indicator. Adaptive algorithms for measuring low-frequency noise parameters are proposed for cases of a given limit error in measuring the power spectral density and a given time for a single measurement. The proposed algorithms include a preliminary estimation of the value of the spectrum shape indicator and subsequent measurement of the noise power spectral density at the optimal filter bandwidth. The optimal filter bandwidth is determined based on the results of a preliminary assessment of the spectrum shape indicator. For both cases, we obtained estimates of the gain in the sense of the average for the set (ensemble) of controlled products. The possibility of adaptive or cognitive adjustment of the measurement system parameters in the control process based on the results of evaluating sample averages in the training sample is discussed.
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Falsini, Naomi, Nicola Calisi, Giammarco Roini, Andrea Ristori, Francesco Biccari, Paolo Scardi, Chiara Barri, Monica Bollani, Stefano Caporali, and Anna Vinattieri. "Large-Area Nanocrystalline Caesium Lead Chloride Thin Films: A Focus on the Exciton Recombination Dynamics." Nanomaterials 11, no. 2 (February 9, 2021): 434. http://dx.doi.org/10.3390/nano11020434.
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Caesium lead halide perovskites were recently demonstrated to be a relevant class of semiconductors for photonics and optoelectronics. Unlike CsPbBr3 and CsPbI3, the realization of high-quality thin films of CsPbCl3, particularly interesting for highly efficient white LEDs when coupled to converting phosphors, is still a very demanding task. In this work we report the first successful deposition of nanocrystalline CsPbCl3 thin films (70–150 nm) by radio frequency magnetron sputtering on large-area substrates. We present a detailed investigation of the optical properties by high resolution photoluminescence (PL) spectroscopy, resolved in time and space in the range 10–300 K, providing quantitative information concerning carriers and excitons recombination dynamics. The PL is characterized by a limited inhomogeneous broadening (~15 meV at 10 K) and its origin is discussed from detailed analysis with investigations at the micro-scale. The samples, obtained without any post-growth treatment, show a homogeneous PL emission in spectrum and intensity on large sample areas (several cm2). Temperature dependent and time-resolved PL spectra elucidate the role of carrier trapping in determining the PL quenching up to room temperature. Our results open the route for the realization of large-area inorganic halide perovskite films for photonic and optoelectronic devices.
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Wang, Songbo, Feifan Wang, Zhiming Su, Xiaoning Wang, Yicheng Han, Lei Zhang, Jun Xiang, Wei Du, and Na Tang. "Controllable Fabrication of Heterogeneous p-TiO2 QDs@g-C3N4 p-n Junction for Efficient Photocatalysis." Catalysts 9, no. 5 (May 10, 2019): 439. http://dx.doi.org/10.3390/catal9050439.
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Photocatalytic technology has been considered to be an ideal approach to solve the energy and environmental crises, and TiO2 is regarded as the most promising photocatalyst. Compared with bare TiO2, TiO2 based p-n heterojunction exhibits a much better performance in charge separation, light absorption and photocatalytic activity. Herein, we developed an efficient method to prepare p-type TiO2 quantum dots (QDs) and decorated graphitic carbonitrile (g-C3N4) nanocomposites, while the composition and structure of the TiO2@g-C3N4 were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectroscopy characterizations. The characterization results reveal the surface decorated TiO2 quantum dots is decomposed by titanium glycerolate, which exhibits p-type conductivity. The presence of p-n heterojunction over interface is confirmed, and photoluminescence results indicate a better performance in transfer and separation of photo-generated charge carriers than pure semiconductors and type-II heterojunction. Moreover, the synergy of p-n heterojunction over interface, strong interface interaction, and quantum-size effect significantly contributes to the promoted performance of TiO2 QDs@g-C3N4 composites. As a result, the as-fabricated TiO2 QDs@g-C3N4 composite with a p/n mass ratio of 0.15 exhibits improved photo-reactivity of 4.3-fold and 5.4-fold compared to pure g-C3N4 in degradation of organic pollutant under full solar spectrum and visible light irradiation, respectively.
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Khurgin, Jacob B. "Relative merits of phononics vs. plasmonics: the energy balance approach." Nanophotonics 7, no. 1 (January 1, 2018): 305–16. http://dx.doi.org/10.1515/nanoph-2017-0048.
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AbstractThe common feature of various plasmonic schemes is their ability to confine optical fields of surface plasmon polaritons (SPPs) into subwavelength volumes and thus achieve a large enhancement of linear and nonlinear optical properties. This ability, however, is severely limited by the large ohmic loss inherent to even the best of metals. However, in the mid- and far-infrared ranges of the spectrum, there exists a viable alternative to metals – polar dielectrics and semiconductors, in which dielectric permittivity (the real part) turns negative in the Reststrahlen region. This feature engenders the so-called surface phonon polaritons, capable of confining the field in a way akin to their plasmonic analogs, the SPPs. Since the damping rate of polar phonons is substantially less than that of free electrons, it is not unreasonable to expect that phononic devices may outperform their plasmonic counterparts. Yet a more rigorous analysis of the comparative merits of phononics and plasmonics reveals a more nuanced answer, namely, that while phononic schemes do exhibit narrower resonances and can achieve a very high degree of energy concentration, most of the energy is contained in the form of lattice vibrations so that enhancement of the electric field and, hence, the Purcell factor is rather small compared to what can be achieved with metal nanoantennas. Still, the sheer narrowness of phononic resonances is expected to make phononics viable in applications where frequency selectivity is important.
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Murzakhanov, Fadis, Boris Yavkin, Georgiy Mamin, Sergei Orlinskii, Ivan Mumdzhi, Irina Gracheva, Bulat Gabbasov, Alexander Smirnov, Valery Davydov, and Victor Soltamov. "Creation of Negatively Charged Boron Vacancies in Hexagonal Boron Nitride Crystal by Electron Irradiation and Mechanism of Inhomogeneous Broadening of Boron Vacancy-Related Spin Resonance Lines." Nanomaterials 11, no. 6 (May 22, 2021): 1373. http://dx.doi.org/10.3390/nano11061373.
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Optically addressable high-spin states (S ≥ 1) of defects in semiconductors are the basis for the development of solid-state quantum technologies. Recently, one such defect has been found in hexagonal boron nitride (hBN) and identified as a negatively charged boron vacancy (VB−). To explore and utilize the properties of this defect, one needs to design a robust way for its creation in an hBN crystal. We investigate the possibility of creating VB− centers in an hBN single crystal by means of irradiation with a high-energy (E = 2 MeV) electron flux. Optical excitation of the irradiated sample induces fluorescence in the near-infrared range together with the electron spin resonance (ESR) spectrum of the triplet centers with a zero-field splitting value of D = 3.6 GHz, manifesting an optically induced population inversion of the ground state spin sublevels. These observations are the signatures of the VB− centers and demonstrate that electron irradiation can be reliably used to create these centers in hBN. Exploration of the VB− spin resonance line shape allowed us to establish the source of the line broadening, which occurs due to the slight deviation in orientation of the two-dimensional B-N atomic plains being exactly parallel relative to each other. The results of the analysis of the broadening mechanism can be used for the crystalline quality control of the 2D materials, using the VB− spin embedded in the hBN as a probe.
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Supriyanto, Edy, Antin Dikayanti, Novita Andriani, Henry Ayu Kartikasari, Rosil Qohhar, and Agus Geter Edy Sutjipto. "Analysis of Absorbance Patterns and Functional Groups of BIO-Dye (Ocimum sanctum) Based on pH Variations in the Wet and Dry Extraction Method." Materials Science Forum 1025 (March 2021): 38–43. http://dx.doi.org/10.4028/www.scientific.net/msf.1025.38.
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Bio-Dye is a dye derived from natural ingredients that have an important role in DSSC performance. This Bio-Dye is later in charge of absorbing sunlight entering the DSSC cells. Bio-Dye is a dye derived from natural ingredients that have an important role in the performance of the DSSC. This Bio-Dye is the one that will be in charge of absorbing sunlight entering the DSSC cells). One important key to know DSSC performance is to pay attention to the quality of the BIO-Dye. A good BIO-Dye can be seen by knowing the absorbance pattern and the function group of the dye its self. This research was conducted to determine absorbance patterns and functional groups based on pH variations in the wet and dry extraction methods contained in the Ocimum sanctum. The absorbance pattern was seen using a UV-Vis spectrophotometer and a functional group using FTIR. The chlorophyll pigment contained in the BIO-Dye (Ocimum sanctum leaf) was extracted using an ethanol solvent and added acetic acid to produce variations in pH values. The UV-Vis spectrometer measurement results showed the highest absorbance pattern was possessed by Ocimum sanctum dye in the dry extraction method and at natural pH (pH = 6.5). The peak absorbance they have is 648 nm, 614 nm, and 537 nm. The FTIR spectrum was obtained from Ocimum sanctum information containing the same functional groups when variations in pH values were carried out in the wet and dry extraction methods. The functional groups are OH groups at wave number 3356.57 cm-1, CH at 2975.37 cm-1, C = O at 1652.50 cm-1, CN at 1383.81 cm-1, C = C at 880.25 cm-1, and CH absorbed at wave number 1087.78 cm-1. In general, it can be concluded that natural dye from Ocimum sanctum has a high absorbance in the visible light region and contains COOH compounds that can strengthen the bond of dye with TiO2 semiconductors so that Ocimum sanctum can be used as a dye in Dye-Sensitized Solar Cells (DSSC).
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Morozhenko, V. O., V. P. Maslov, I. V. Bariakhtar, and N. V. Kachur. "Determination of the parameters of coherent magneto-optical layers on a finite absorbing substrate from thermal radiation spectra." Semiconductor Physics, Quantum Electronics and Optoelectronics 23, no. 04 (November 19, 2020): 400–407. http://dx.doi.org/10.15407/spqeo23.04.400.
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A possibility of determining the parameters of a coherent magneto-optical layer on a finite incoherent absorbing substrate by analyzing the spectra of its thermal radiation (TR) has been investigated. On the example of a plane-parallel InAs semiconductor plate silver-coated on the back surface, it has been shown that a complex analysis of TR spectra, both without and with the presence of magnetic field, makes it possible to determine the thickness, optical, magneto-optical and electric parameters of the layer. Algorithms for the calculation and analysis of TR spectra are adduced, which simplify determination of layer parameters and increase the accuracy of results. Comparing the position of the extremes of the experimental zero-field spectrum with the theoretical calculations, the thickness of the sample and the plasma oscillation frequency in the used semiconductor have been determined. The analysis of the relative contrast of interference oscillations in the TR spectrum in the magnetic field using previously defined parameters enabled to ascertain the spectral dependence of the Faraday rotation angle and to determine the concentration, effective mass and type of current carriers. It has been assumed, that such analysis of luminescence spectra also allows determining the parameters of magneto-optical layers and structures.
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Cho, Min Kook, Ho Kyung Kim, Thorsten Graeve, and Jung Min Kim. "Characterization of CMOS Pixel Detectors for Digital X-Ray Imaging." Key Engineering Materials 321-323 (October 2006): 1052–55. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1052.
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In order to develop a cost-effective digital X-ray imaging system, we considered a CMOS (complementary metal-oxide-semiconductor) photodiode array in conjunction with a scintillation screen. Imaging performance was evaluated in terms of MTF (modulation-transfer function), NPS (noise-power spectrum) and DQE (detective quantum efficiency). The presampled MTF was measured using a slanted-slit method. The NPS was determined by 2-dimensional Fourier analysis. Both the measured MTF and NPS, and a self-developed computational model for the X-ray spectral analysis were used to determine the spatial frequency-dependent DQE. From the measured MTF, the spatial resolution was found to be about 10.5 line pairs per millimeter (lp/mm). For a 45-kVp tungsten spectrum, the measured DQE around zero spatial frequency was about 40%.
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Widhiyanuriyawan, Denny, Prihanto Trihutomo, Sudjito Soeparman, and Lilis Yuliati. "Zwitterion Effect of Cow Brain Protein towards Efficiency Improvement of Dye-Sensitized Solar Cell (DSSC)." Scientific World Journal 2020 (February 19, 2020): 1–12. http://dx.doi.org/10.1155/2020/7910702.
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Dye-Sensitized Solar Cell (DSSC) constitutes a solar cell using natural dyes from plants that are adsorbed in semiconductors to convert solar energy into electrical energy. DSSC has relatively inexpensive fabrication costs, is easy to produce, works in visible light, and is environmentally friendly. The disadvantage of DSSC is that its efficiency is still low compared to silicon solar cells. This low efficiency is due to obstacles in the flow of electric current on DSSC. In this study, DSSC has been successfully fabricated with the deposition of clathrin protein from cow brain. The zwitterions effect of protein on cow brain is able to reduce resistance and increase electric current on DSSC. The zwitterions effect of cow brain protein that fills gaps or empty spaces between TiO2 particles generates acidic reactions (capturing electrons) and bases (releasing electrons); hence, proteins in the cow brain are able to function as electron bridges between TiO2 molecules and generate an increase in electric current in DSSC. The method used in this research was to deposit clathrin protein from cow brain in a porous TiO2 semiconductor with a concentration of 0%, 25%, 50%, and 75%. Tests carried out on DSSC that have been performed were X-Ray Diffractometer (XRD) testing to determine the crystal structure formed, Fourier Transform Infrared Spectroscopy (FTIR) testing to determine the functional groups formed on DSSC, Scanning Electron Microscopy (SEM) testing to determine the surface morphological characteristics of the DSSC layer, and testing the efficiency using AM 1.5 G solar simulator (1000 W/m2) to determine the efficiency changes that occur in DSSC. From the XRD test results by increasing the concentration of cow brain protein in DSSC, the structure of amino acid crystals also increased and the crystal size increased with the largest crystal size of 42.25 nm at the addition of 75% of cow brain protein. FTIR test results show that the addition of cow brain protein will form functional protein-forming amino groups on DSSC. FTIR analysis shows the sharp absorption of energy by protein functional groups in the FTIR spectrum with increasing concentration of cow brain protein in DSSC. The SEM test results show that the concentration of additional molecules of protein deposited into TiO2 increases and the cavity or pore between the TiO2 molecules decreases. The reduction of cavities in the layers indicates that protein molecules fill cavities that exist between TiO2 molecules. From the results of testing using AM 1.5 G solar simulator (1000 W/m2), the highest efficiency value is 1.465% with the addition of 75% brain protein concentration.
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Kerkhoven, Thomas. "A Spectral Analysis of the Decoupling Algorithm for Semiconductor Simulation." SIAM Journal on Numerical Analysis 25, no. 6 (December 1988): 1299–312. http://dx.doi.org/10.1137/0725073.
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Sharma, Shelja, Alex O. Ibhadon, M. Grazia Francesconi, Surinder Kumar Mehta, Sasikumar Elumalai, Sushil Kumar Kansal, Ahmad Umar, and Sotirios Baskoutas. "Bi2WO6/C-Dots/TiO2: A Novel Z-Scheme Photocatalyst for the Degradation of Fluoroquinolone Levofloxacin from Aqueous Medium." Nanomaterials 10, no. 5 (May 8, 2020): 910. http://dx.doi.org/10.3390/nano10050910.
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Photocatalytic materials and semiconductors of appropriate structural and morphological architectures as well as energy band gaps are materials needed for mitigating current environmental problems, as these materials have the ability to exploit the full spectrum of solar light in several applications. Thus, constructing a Z-scheme heterojunction is an ideal approach to overcoming the limitations of a single component or traditional heterogeneous catalysts for the competent removal of organic chemicals present in wastewater, to mention just one of the areas of application. A Z-scheme catalyst possesses many attributes, including enhanced light-harvesting capacity, strong redox ability and different oxidation and reduction positions. In the present work, a novel ternary Z-scheme photocatalyst, i.e., Bi2WO6/C-dots/TiO2, has been prepared by a facile chemical wet technique. The prepared solar light-driven Z-scheme composite was characterized by many analytical and spectroscopic practices, including powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption–desorption isotherm, Fourier-transform infrared spectroscopy (FT-IR), photoluminescence (PL) and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the Bi2WO6/C-dots/TiO2 composite was evaluated by studying the degradation of fluoroquinolone drug, levofloxacin under solar light irradiation. Almost complete (99%) decomposition of the levofloxacin drug was observed in 90 min of sunlight irradiation. The effect of catalyst loading, initial substrate concentration and pH of the reaction was also optimized. The photocatalytic activity of the prepared catalyst was also compared with that of bare Bi2WO6, TiO2 and TiO2/C-dots under optimized conditions. Scavenger radical trap studies and terephthalic acid (TPA) fluorescence technique were done to understand the role of the photo-induced active radical ions that witnessed the decomposition of levofloxacin. Based on these studies, the plausible degradation trail of levofloxacin was proposed and was further supported by LC-MS analysis.
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Et.al, DalievKhojiakbarSultanovich. "Increasing the Thermostability of Optoelectronic Devices on Semiconductor Radiators." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 3 (April 10, 2021): 3112–19. http://dx.doi.org/10.17762/turcomat.v12i3.1535.
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The article proposes a scheme for thermal stabilization of the radiation flux of mid-IR LEDs in the temperature range + 20 ° C + 80 ° C. It is shown that the relevance of mid-IR LEDs for solving problems of gas analysis, environmental monitoring, moisture measurement and medical diagnostics. It was revealed that the guarantee of the measurement accuracy and sensitivity of optoelectronic devices is the correct spectral matching of the photodetector, LED and absorption of the investigated substance. The disadvantages of emitting diodes associated with time and temperature instability during operation are considered. A study of the spectral characteristics of mid-IR LEDs at various temperatures showed that the wavelength at the maximum the emission spectrum increases almost linearly with increasing temperature, which leads to additional errors and lowers the measurement accuracy of optoelectronic devices. A schematic diagram is proposed for stabilizing the radiation flux of mid-IR LEDs in the temperature range + 20 ° C + 80 ° C..
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Kreisbeck, Carolin, and Luísa Mascarenhas. "Asymptotic spectral analysis in semiconductor nanowire heterostructures." Applicable Analysis 94, no. 6 (June 2, 2014): 1153–91. http://dx.doi.org/10.1080/00036811.2014.919052.
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Warashina, Masatoshi, and Michio Tajima. "Spectral Shape Analysis of Photoluminescence Excitation in Semiconductors." Japanese Journal of Applied Physics 35, Part 1, No. 1A (January 15, 1996): 120–23. http://dx.doi.org/10.1143/jjap.35.120.
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Jhang, Kyung Young, Kimio Sasaki, Job Ha, and Hiroaki Tanaka. "Advanced Technologies for Estimation of Nonlinear Ultrasonic Parameter." Key Engineering Materials 326-328 (December 2006): 673–76. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.673.
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This paper proposes an advanced signal processing technique for the precise estimation of a nonlinear ultrasonic parameter, based on power spectral and bispectral analysis. The power spectrum and bispectrum estimation of the pulse-like ultrasonic signal used in the commercial SAM (scanning acoustic microscopy) equipment is especially considered in this study. The usefulness of the proposed estimation is confirmed by experiments for a Newton ring with a continuous air gap and a real semiconductor sample with local delaminations. The results show that the nonlinear parameter obtained by the proposed method had a good correlation with the delamination.
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Umana-Membreno, G. A., J. Antoszewski, and L. Faraone. "Mobility spectrum analysis of carrier transport at insulator/semiconductor interfaces." Microelectronic Engineering 109 (September 2013): 232–35. http://dx.doi.org/10.1016/j.mee.2013.03.062.
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Lim, Munwon, and Suk Joo Bae. "Spatial Monitoring of Wafer Map Defect Data Based on 2D Wavelet Spectrum Analysis." Applied Sciences 9, no. 24 (December 15, 2019): 5518. http://dx.doi.org/10.3390/app9245518.
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Since machine vision systems (MVS) lead to a wide usage of monitoring systems for industrial applications, the research on the statistical process control (SPC) of image data has been promoted as an automated method for early detection and prevention of unusual conditions in manufacturing processes. In this paper, we propose a non-parametric SPC approach based on the 2D wavelet spectrum (WS-SPC) to extract the feature that contains the spatial and directional information of each subspace in an image. Using the 2D discrete wavelet transform and spectrum analysis, the representative statistic, the Hurst index, is calculated, and a single matrix space that consists of estimated statistics is reconstructed into a spatial control area for SPC. When a control limit is determined by the density of statistics, real-time monitoring based on WS-SPC is available for time releasing images. In the application, an analysis of wafer bin maps (WBMs) is conducted at a semiconductor company in Korea in order to evaluate the performance of the suggested approach. The results show that the proposed method is effective in terms of its fast computation speed and spectral monitoring.
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Джахангирли, З. А., Т. Г. Керимова, И. А. Мамедова, С. А. Набиева, and Н. А. Абдуллаев. "Ab initio и экспериментальное исследование электронных, оптических и колебательных свойств CdGa-=SUB=-2-=/SUB=-Te-=SUB=-4-=/SUB=-." Физика твердого тела 62, no. 8 (2020): 1270. http://dx.doi.org/10.21883/ftt.2020.08.49613.024.
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The electronic, optical, and lattice vibrational properties of CdGa2Te4 were studied experimentally using spectral ellipsometry, Raman scattering (Raman scattering) and infrared (IR) spectroscopy, as well as theoretically using the density functional theory (DFT). Eight Raman-active modes and twelve IR-active modes were detected and identified from consideration of the point group symmetry. Based on the analysis of the electronic spectrum and the density of states, the nature of the chemical bond in this semiconductor compound is determined. The theoretically calculated results are compared with the experimental data of the present work and with the results of experimental data available in the literature obtained by infrared spectroscopy and Raman scattering.
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Tang, Lin, Jianwei Zhang, Kaibo Shi, Bingqi Liu, Xingyue Liu, Yongxin Zhao, Yuepeng Li, et al. "Application of an Improved Seeds Local Averaging Algorithm in X-ray Spectrum." Mathematical Problems in Engineering 2021 (March 31, 2021): 1–8. http://dx.doi.org/10.1155/2021/5545818.
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As an element content analysis technology, X-ray fluorescence spectrometry can be used for quantitative or semiquantitative analysis of the element content in the sample, which is of great significance for mineral census and spent fuel reprocessing. Due to the limitation of the inherent energy resolution of the detector itself, the accuracy of X-ray fluorescence analysis is difficult to be greatly improved. In some applications, even if the semiconductor detector with the best energy resolution is used, the characteristic peaks of different elements cannot be completely separated. Therefore, greatly improving the energy resolution of the detection system is a hot issue in the existing research field. To solve these problems, this paper analyzes the advantages and disadvantages of the traditional MCA (multichannel analyzer) and SLA (seeds local averaging) algorithm and proposes an ISLA (improved seeds local averaging) algorithm based on mathematical statistics. In the section of theoretical derivation, the principle of ISLA algorithm is described, whose theoretical characteristics and spectral results with different parameters are derived and simulated. In the application effect evaluation, the spectrum obtained by each method is analyzed in detail. Simulation and experimental results show that the spectrum obtained by SLA algorithm has a smaller full width at half maximum than that obtained by MCA, but the seed average process in SLA algorithm also reduces its counting rate. The optimized ISLA algorithm can not only effectively reduce the full width at half maximum of the spectral line and sharpen the spectrum peak but also compensate for the loss of the count rate of SLA algorithm.
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Sharaiha, A., and M. Guegan. "Analysis of selective photodetection spectrum response of a semiconductor optical amplifier." Microwave and Optical Technology Letters 19, no. 6 (December 20, 1998): 457–60. http://dx.doi.org/10.1002/(sici)1098-2760(19981220)19:6<457::aid-mop20>3.0.co;2-t.
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KLEMENT, STEPHAN, KARL W. KRATKY, and JOHANN NITTMANN. "PRACTICAL TIME-SERIES ANALYSIS WITH MULTIFRACTAL METHODS." Fractals 01, no. 03 (September 1993): 735–43. http://dx.doi.org/10.1142/s0218348x93000770.
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Time-series data of various origins are studied by analyzing their corresponding multifractal f(α)-spectral which are obtained by use of the so-called canonical method. The classes of data samples under investigation include: (a) airborne particle count data taken from an industrial cleanroom environment; (b) data generated by use of a (pseudo-)random number generator; and (c) data resulting from the iteration of the logistic map for the value r=4.0 of the control parameter, thus exhibiting chaotic behavior. From the resulting multifractal spectra, typical features of the f(α)-curve can be identified in relation to the corresponding class of original data. These findings can be of interest for various purposes. One application under consideration is the processing of microcontamination particle data recorded in high-quality cleanrooms. These are of great importance to the increasing miniaturization of semiconductor devices. In processing microcontamination particle data, the multifractal analysis can help to extract significant information from an enormous number of data to compress these data into a reasonable quantity. Another interesting aspect can be found in using the multifractal spectrum as a possible instrument for estimating the quality and performance of a random number generator.
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LIU, AI HUA. "Spectrum analysis of plasma produced by pulsed laser ablation of GaAs." Journal of Plasma Physics 73, no. 2 (April 2007): 231–39. http://dx.doi.org/10.1017/s002237780600448x.
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Abstract.A time-resolved diagnostic technique was used to investigate the emission spectra from the plasmas produced by 1.06 μm, 10 ns pulsed laser ablation of semiconductor GaAs. The characteristics of the species in plasma produced at different ambient pressure were analyzed. The full width at half maximum of the spectral line was measured and analyzed according to obtained spectra of the excited atoms; several line broadening factors were estimated according to our experimental conditions and the results indicate that the Stark broadening is the main broadening mechanism. Under the assumption of local thermodynamic equilibrium, the time evolution of electron number density was deduced from the Stark broadening measurements.
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Sun, Chang Long, Zhen Ping Wu, Shi Jie Lu, Zhen Ren, Yue Hua An, Dao You Guo, Xun Cai Guo, Xu Long Chu, and Wei Hua Tang. "Determination of the Optical Constants of Gallium Oxide Films." Advanced Materials Research 986-987 (July 2014): 42–46. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.42.
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Transmission spectrum and reflectance spectrum have long been used to characterize gap semiconductor. Transmission spectrum can be measured very directly, but the influence of substrate absorption is often unavoidable. However, when using the reflectance spectrum measurement, the absorption of thin film, substrate absorption, and coherent interference will make the reflectance spectrum much more complicated. In this paper, Considering the absorption of thin film, substrate absorption, and coherent interference, we use the envelope curves algorithm to achieve the calculation formula of refractive index deduced from the reflectance spectrum. Through the analysis of the reflectance spectrum of Ga2O3film, we achieved thickness of the film, refractive index, extinction and absorption coefficient and dispersion constant.
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Delaye, Ph, H. J. Von Bardeleben, and G. Roosen. "Bulk Photorefractive Semiconductors." MRS Bulletin 19, no. 3 (March 1994): 39–43. http://dx.doi.org/10.1557/s0883769400039671.
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The photorefractive (PR) effect has been studied for more than 25 years and many applications for optical signal processing such as correlation, real-time holography, dynamic interconnections, and optical memories have been developed. The main focus of study for the PR effect has been oxides (ferroelectrics and sillenites) in which the useful spectral range lies in the visible. Applications for telecommunication systems and eye-safe devices have required extending the spectral range into the near infrared (1.0 to 1.5 μm), and so the exploration of different materials. It has been shown that the bulk semi-insulating III-V semiconductors GaAs and InP, and more recently the II-VI compound CdTe, were efficient materials for this spectral range. III-V materials offer the advantage of availability as bulk semiinsulating materials of high crystalline perfection and homogeneity regarding their electrical properties due to their importance as substrate materials in micro and optoelectronic technology. However, these materials have not been optimized for PR applications, so quantitative analyses of PR experiments related to the specific material defect properties are necessary for further developments. It has equally been shown that the PR effect can be used as an efficient tool for materials characterization.