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Journal articles on the topic 'Energy band gap'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Zhanabaev, Z. Zh. "WIDTH OF ENERGY BAND GAP OF NANOPOROUS SEMICONDUCTOR FILMS." Eurasian Physical Technical Journal 17, no. 2 (December 24, 2020): 39–44. http://dx.doi.org/10.31489/2020no2/39-44.

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The aim of this work is to experimentally clarify the reasons for the appearance of jumps in the current and memory of semiconductor nanoporous structures.Porous nanostructures were obtained by electrochemical etching. The current-voltage characteristics of the samples were measured for porous silicon and on thin films of a chalcogenide glassy semiconductor. The existence of jump-like switching and current hysteresis in porous silicon nanofilms under laser illumination is shown experimentally.A connection between the switching voltage values and the dependence of the band gap on the porosity of nanofilms is found. These results make it possible to construct a theory of current switching and its hysteresis based on the concepts of the theory of second-order phase transitions.

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2

Plekhanov, V. G., and N. V. Plekhanov. "Isotope dependence of band-gap energy." Physics Letters A 313, no. 3 (June 2003): 231–37. http://dx.doi.org/10.1016/s0375-9601(03)00760-6.

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3

Nag, B. R. "Direct band-gap energy of semiconductors." Infrared Physics & Technology 36, no. 5 (August 1995): 831–35. http://dx.doi.org/10.1016/1350-4495(95)00023-r.

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4

Et. al., Sharibayev Nosirjon Yusufjanovich,. "Temperature Dependence Of Energy States And Band Gap Broadening." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 4 (April 11, 2021): 53–60. http://dx.doi.org/10.17762/turcomat.v12i4.471.

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Statistical analysis of energy levels is carried out. The density of surface states of MIS structures based on silicon is investigated. A mathematical model is constructed for the temperature dependence of the spectrum of the density of surface states for a wide energy range. A formula is derived for the density of surface states as a function of temperature. The thermal contributions of the expanded bands to the band gap of the semiconductor are taken into account. The resulting formula allows one to determine the density of energy states in the forbidden band in an explicit form, without taking into account the influence of the broadening of the allowed bands. This improves the accuracy of determining the concentration of impurities and defects in silicon.

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5

Patidar, Dinu, K. S. Rathore, N. S. Saxena, Kananbala Sharma, and T. P. Sharma. "Energy Band Gap Studies of CdS Nanomaterials." Journal of Nano Research 3 (October 2008): 97–102. http://dx.doi.org/10.4028/www.scientific.net/jnanor.3.97.

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The CdS nanoparticles of different sizes are synthesized by a simple chemical method. Here, CdS nanoparticles are grown through the reaction of solution of different concentration of CdCl2 with H2S. X-ray diffraction pattern confirms nano nature of CdS and has been used to determine the size of particle. Optical absorption spectroscopy is used to measure the energy band gap of these nanomaterials by using Tauc relation. Energy band gap ranging between 3.12 eV to 2.47 eV have been obtained for the samples containing the nanoparticles in the range of 2.3 to 6.0 nm size. A correlation between the band gap and size of the nanoparticles is also established.

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6

Boakye, F., and D. Nusenu. "The energy band gap of cadmium sulphide." Solid State Communications 102, no. 4 (April 1997): 323–26. http://dx.doi.org/10.1016/s0038-1098(97)00012-4.

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7

Paduano, Qing S., David W. Weyburne, Lionel O. Bouthillette, Shen-Qi Wang, and Michael N. Alexander. "The Energy Band Gap of AlxGa1-xN." Japanese Journal of Applied Physics 41, Part 1, No. 4A (April 15, 2002): 1936–40. http://dx.doi.org/10.1143/jjap.41.1936.

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8

Zhong, Shuying, Musheng Wu, and Xueling Lei. "First-principle calculations of effective mass of silicon crystal with vacancy defects." Materials Science-Poland 34, no. 4 (December 1, 2016): 916–23. http://dx.doi.org/10.1515/msp-2016-0128.

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AbstractThe energy band structures and electron (hole) effective masses of perfect crystalline silicon and silicon with various vacancy defects are investigated by using the plane-wave pseudopotential method based on density functional theory. Our results show that the effect of monovacancy and divacancy on the energy band structure of crystalline silicon is primarily reflected in producing the gap states and the local states in valence band maximum. It also causes breaking the symmetry of energy bands resulting from the Jahn-Teller effect, while only producing the gap states for the crystalline silicon with hexavacancy ring. However, vacancy point defects could not essentially affect the effective masses that are derived from the native energy bands of crystalline silicon, except for the production of defect states. Simultaneously, the Jahn-Teller distortions only affect the gap states and the local states in valence band maximum, but do not change the symmetry of conduction band minimum and the nonlocal states in valence band maximum, thus the symmetry of the effective masses. In addition, we study the electron (hole) effective masses for the gap states and the local states in valence band maximum.

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9

Indriani, Devi, Helga Dwi Fahyuan, and Ngatijo Ngatijo. "UJI UV-VIS LAPISAN TiO2/N2 UNTUK MENENTUKAN BAND GAP ENERGY." JOURNAL ONLINE OF PHYSICS 3, no. 2 (November 13, 2018): 6–10. http://dx.doi.org/10.22437/jop.v3i2.5142.

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[Title: TEST UV-VIS LAYER TiO2/N2 FOR DETERMINING BAND GAP ENERGY] The effect of nitrogen doping variation on energy band gap in TiO2 layer grown by doctor blade technique. The TiO2/N2 layer was prepared with concentrations of 0%, 15%, 25% and 25% calcined at 500°C for 3 hours. Characterization of band gap energy by using the UV-Vis spectrometer at a wavelength range of 200 nm-700 nm. The band gap energy is obtained by using the Swanepoel equation and Touch Plot method. The results showed that doping of nitrogen can decrease the band gap energy of 3.9250 eV, 3.8750 eV, 3.8375 eV and 3.9125 eV, respectively. The smallest energy band gap is obtained at 25% concentration that is 3.8375eV. Keywords: Coating TiO2/N2, transmittance, Band gap energy

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10

Diwan, Bhoopendra Dhar, and Vinod Kumar Dubey. "Influence of Size on Effective Band Gap of Silicon Nano-Wire." Advanced Materials Research 938 (June 2014): 322–26. http://dx.doi.org/10.4028/www.scientific.net/amr.938.322.

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In this article, the effect of wire-size on the effective band gap of Silicon (Si) is analyzed. The band gap is one of the most significant electronic parameters of semiconductor material. The band gap of semiconductor depends on temperature, pressure, composition, number of atoms as well as on the size of the particle. When semiconductors are synthesized at nanoscale level, their small particle size gives rise to quantum confinement and the energy bands are split into discrete levels. It is observed that effective band gap of semi-conductor depends on the size of the wire (number of atoms and dimensions) and it increases by decreasing the size of Si nanowire. The size quantization effect is noticed as a shift of the effective band gap toward lower values with increasing temperature of Si nanowire which also shows increase in atomic vibrations. Keywords: Size effect; Energy band gap; Semiconductor, effective mass; nanowire.

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11

Panda, Rudrashish, Sivabrata Sahu, and G. C. Rout. "Enhancement of the Metallic Behavior of Graphene due to Coulomb Interaction in the Paramagnetic Limit: A Tight-Binding Study." International Journal of Nanoscience 17, no. 04 (July 8, 2018): 1760031. http://dx.doi.org/10.1142/s0219581x17600316.

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The pristine graphene is a zero band gap semiconductor with valence and conduction bands touching each other at Dirac points. The graphene-on-substrate exhibits a small gap at the Dirac points. The microscopic Hamiltonian describes the nearest-neighbor [Formula: see text]-electron hopping with tight-binding approach. Graphene-on-substrate exhibits a gap at the Dirac points where the energy at A sublattice is raised by [Formula: see text] and the energy at B sublattice is lowered by energy [Formula: see text] leading to asymmetry in the two sublattices. Further, we have introduced impurities at both the sublattices. The Coulomb interaction in graphene-on-substrate is described by Hubbard-type Coulomb interaction with energy U. The Coulomb interaction is treated in the calculation within the mean-field approximation in the paramagnetic limit. The temperature-dependent site-independent electron occupancies at both the sublattices are calculated and computed self-consistently. The difference between the electron occupancies of both the sublattices introduces a charge gap. The effect of charge gap on the electronic band dispersion in graphene-on-substrate is investigated by varying different model parameters of the system like Coulomb energy, substrate-induced gap, temperature, total band filling and impurity concentrations. It is observed that both the valence and conduction bands are shifted above the Fermi level exhibiting a charge gap between the bands. As a result, the partially filled valence band exhibits metallic behavior.

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12

Guan, Jinyue, and Lei Xu. "Energy Gaps in BN/GNRs Planar Heterostructure." Materials 14, no. 17 (September 5, 2021): 5079. http://dx.doi.org/10.3390/ma14175079.

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Using the tight-binding approach, we study the band gaps of boron nitride (BN)/ graphene nanoribbon (GNR) planar heterostructures, with GNRs embedded in a BN sheet. The width of BN has little effect on the band gap of a heterostructure. The band gap oscillates and decreases from 2.44 eV to 0.26 eV, as the width of armchair GNRs, nA, increases from 1 to 20, while the band gap gradually decreases from 3.13 eV to 0.09 eV, as the width of zigzag GNRs, nZ, increases from 1 to 80. For the planar heterojunctions with either armchair-shaped or zigzag-shaped edges, the band gaps can be manipulated by local potentials, leading to a phase transition from semiconductor to metal. In addition, the influence of lattice mismatch on the band gap is also investigated.

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13

Syarif, Nirwan, Dedi Rohendi, Sri Haryati, and Claudia Kartika Sari Dewi. "The Effects of Grain Size, Oxidizers and Catalysts on Band Gap Energy of Gelam-Wood Carbon." International Journal of Sustainable Transportation Technology 2, no. 2 (October 31, 2019): 63–70. http://dx.doi.org/10.31427/ijstt.2019.2.2.5.

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The research of the effects of grain size, oxidizers, and catalysts on band gap energy of gelam-wood carbon has been conducted in which the carbons were produced from gelam-wood pyrolysis in high temperatures. The instrumentations used in this study were UV-Vis, FTIR spectrophotometer, and SEM. SEM and FTIR were used to characterize the morphology and the functionality of the carbon surface. UV-Vis spectrograms showed that the electronic property of carbon such as band gap was affected when grain size and surface area were changed. The increase of the functional groups in carbon occurred as the surface area of the carbon was increased. Band gap energy of crystalline carbon became much lower along with the increase in grain size due to the effects of bands-broadening. FTIR spectrograms showed that the carbon contained of hydroxyl and carboxylic groups. The hydroxyls were derived from steam-oxidized carbon that was provided narrower in the interlayer distance and lower-set band gap energy. Carboxylic groups were derived from acid nitric oxidation causing flat layer to become curved. The layers were wider and the band energy was higher. The main factor that affects the electronic structure of metal oxide in carbon/metal oxide composites was atomic alignments. The band gap energy increased along with the increase of the asymmetry alignments in metal oxide.

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14

Kyaw, Wut Hmone, and May Nwe Myint Aye. "Simulation of Energy Bands for Metal and Semiconductor Junction." Journal La Multiapp 1, no. 2 (June 21, 2020): 7–13. http://dx.doi.org/10.37899/journallamultiapp.v1i2.107.

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This paper presents the metal-semiconductor band structure analysis for metal-oxide semiconductor field effect transistor (MOSFET). The energy bands were observed at metal-semiconductor and semiconductor-metal junctions. The simulation results show energy variations by using gallium-nitride (GaN) material. Gallium nitride based MOSFETs have some special material properties and wide band-gap. From the energy band, the condition of contact potential, conduction and valence band-edges can be analyzed. The computerized simulation results for getting the band layers are investigated with MATLAB programming language.

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15

Zhao, Chuan Zhen, Li Yuan Yu, Chun Xiao Tang, Ming Li, and Jian Xin Zhang. "A New Model of Discribing the Band Gap Bowing of III Nitride Alloys." Advanced Materials Research 298 (July 2011): 7–12. http://dx.doi.org/10.4028/www.scientific.net/amr.298.7.

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In the paper, a model is developed to discribe the band gap energy of Ⅲ nitride alloys. A new parameter A is used to discribe the band gap bowing. The new bowing parameter A is obtained by fitting the experimental values of the band gap energy. AAlGaN =0.46, AInGaN =0.59 and AInAlN =1.90 are obtained by fitting the experimental values of the band gap energy for AlGaN, InGaN and InAlN, respectively. The model is also suitable to discribe the band gap energy of other Ⅲ-Ⅴ ternary alloys.

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16

Kosyachenko, L. A. "Energy band gap and electrical conductivity of Cd1–xMnxTe alloys with different manganese content." Semiconductor Physics Quantum Electronics and Optoelectronics 14, no. 4 (December 5, 2011): 421–26. http://dx.doi.org/10.15407/spqeo14.04.421.

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17

Rudko, G. Yu, I. A. Buyanova, W. M. Chen, H. P. Xin, and C. W. Tu. "Temperature behavior of the GaNP band gap energy." Solid-State Electronics 47, no. 3 (March 2003): 493–96. http://dx.doi.org/10.1016/s0038-1101(02)00401-x.

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18

Agarwal, Anant, Woong Je Sung, Laura Marlino, Pawel Gradzki, John Muth, Robert Ivester, and Nick Justice. "Wide Band Gap Semiconductor Technology for Energy Efficiency." Materials Science Forum 858 (May 2016): 797–802. http://dx.doi.org/10.4028/www.scientific.net/msf.858.797.

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The attributes and benefits of wide-bandgap (WBG) semiconductors are rapidly becoming known, as their use in power electronics applications continues to gain industry acceptance. However, hurdles still exist in achieving widespread market acceptance, on a par with traditional silicon power devices. Primary challenges include reducing device costs and the expansion of a workforce trained in their use. The Department of Energy (DOE) is actively fostering development activities to expand application spaces, achieve acceptable cost reduction targets and grow the acceptance of WBG devices to realize DOEs core missions of more efficient energy generation, greenhouse gas reduction and energy security within the U.S. This paper discusses currently funded activities and application areas that are suitable for WBG introduction. A detailed cost roadmap for SiC device introduction is also presented.

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19

Menezes, O. L. T. De, and A. A. Aligia. "k-Dependent Energy Gap in Two Band Superconductors." Japanese Journal of Applied Physics 26, S3-2 (January 1, 1987): 1231. http://dx.doi.org/10.7567/jjaps.26s3.1231.

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20

Enhessari, Morteza. "FeAl2O4 Nanopowders; Structural Analysis and Band Gap Energy." High Temperature Materials and Processes 36, no. 8 (September 26, 2017): 789–93. http://dx.doi.org/10.1515/htmp-2015-0229.

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AbstractNanoscale FeAl2O4 was successfully synthesized via sol–gel method. The sol constituents containing iron and aluminum cations were formed homogenously in stearic acid gel (formation of organic precursor). The pure structural analysis and the size of the spinels were confirmed by X-ray diffraction (XRD). It was observed that the size of the nanoscale materials obtained at around 30–40nm. The micrographs of FeAl2O4 evidenced the homogenous and nanosize formation of spinel. The semiconducting behavior of this mixed metal oxide was observed at 3.14eV based on the band gap energy (Eg). The final nanoscale materials exhibited a superparamagnetic behavior with a saturation magnetization of 9.8 emu/g at applied field of 10 kOe.

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21

Konnikov, S. G., and V. E. Umansky. "Energy band-gap in elastic-strained heteroepitaxial layers." Crystal Research and Technology 20, no. 10 (October 1985): 1381–86. http://dx.doi.org/10.1002/crat.2170201013.

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22

Honda, Tohru, Masao Shibata, Makoto Kurimoto, Mieko Tsubamoto, Jun Yamamoto, and Hideo Kawanishi. "Band-Gap Energy and Effective Mass of BGaN." Japanese Journal of Applied Physics 39, Part 1, No. 4B (April 30, 2000): 2389–93. http://dx.doi.org/10.1143/jjap.39.2389.

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23

Licht, Stuart. "Multiple Band Gap Semiconductor/Electrolyte Solar Energy Conversion." Journal of Physical Chemistry B 105, no. 27 (July 2001): 6281–94. http://dx.doi.org/10.1021/jp010552j.

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24

Van Stryland, Eric W., M. A. Woodall, H. Vanherzeele, and M. J. Soileau. "Energy band-gap dependence of two-photon absorption." Optics Letters 10, no. 10 (October 1, 1985): 490. http://dx.doi.org/10.1364/ol.10.000490.

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25

Malerba, Claudia, Francesco Biccari, Cristy Leonor Azanza Ricardo, Matteo Valentini, Rosa Chierchia, Melanie Müller, Antonino Santoni, et al. "CZTS stoichiometry effects on the band gap energy." Journal of Alloys and Compounds 582 (January 2014): 528–34. http://dx.doi.org/10.1016/j.jallcom.2013.07.199.

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26

Ram, R. S., O. M. Prakash, and A. N. Pandey. "Photoacoustic determination of energy band gap of semiconductors." Pramana 28, no. 3 (March 1987): 293–97. http://dx.doi.org/10.1007/bf02845606.

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27

Evingür, Gülşen Akın, and Önder Pekcan. "Optical energy band gap of PAAm-GO composites." Composite Structures 183 (January 2018): 212–15. http://dx.doi.org/10.1016/j.compstruct.2017.02.058.

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28

LI, KEYAN, YANJU LI, and DONGFENG XUE. "BAND GAP ENGINEERING OF CRYSTAL MATERIALS: BAND GAP ESTIMATION OF SEMICONDUCTORS VIA ELECTRONEGATIVITY." Functional Materials Letters 05, no. 02 (June 2012): 1260002. http://dx.doi.org/10.1142/s1793604712600028.

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We have developed empirical equations to quantitatively calculate the band gap values of binary ANB8-N and ternary ABC2 chalcopyrite semiconductors from the general viewpoint of chemical bonding processes upon electronegativity (EN). It is found that the band gap of crystal materials is essentially determined by the binding energy of chemical bonds to the bonding electrons, which can be effectively described by the average attractive abilities of two bonded atoms to their valence electrons and the delocalization degree of the valence electrons. The calculated band gap values of a large number of compounds can agree well with the available experimental data. This work provides us an efficient approach to quantitatively predict the band gap values of inorganic crystal materials on the basis of fundamental atom parameters such as EN, atomic radius, etc.

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29

Hu, H. F., Y. B. Li, and K. L. Yao. "The electronic band structure of polydiacetylenes with second- and third-neighbor hopping interaction." Canadian Journal of Physics 79, no. 4 (April 1, 2001): 749–56. http://dx.doi.org/10.1139/p01-035.

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We have studied the energy band structure of polydiacetylenes (PDAs) using the extensional Hückel Hamiltonian that includes the nonnearest-neighbor hopping interactions. The results show that with increase in the nonnearest-neighbor hopping interaction parameters ρ1 and ρ2, (i) the energy band symmetry is broken and the energy gap 2Δ has changed, (ii) the locations and the widths of energy bands have changed and their shifts depend mainly on ρ1 (next-neighbor hopping interactions), and (iii) the energy gap 2Δ depends mainly on ρ2 (third-neighbor hopping interactions), the effects of the nonnearest-neighbor hopping interaction on the band structure are discussed. PACS No.: 31.15Ct

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30

Jayawardana, K. B. S. K. B., and K. A. I. L. Wijewardena Gamalath. "Study on the Photonic Band Gaps of the Face Centered Cubic Crystals." International Letters of Chemistry, Physics and Astronomy 70 (September 2016): 63–75. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.70.63.

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Since the dielectric contrast of photonic crystals play an important role in determining the existence of a photonic gap, the photonic energy bands, density of states of face centered cubic structured photonic crystals formed from spheres of several dielectric materials placed in air were calculated using the plane wave expansion method. A complete band gap was obtained between second and third bands with a gap to mid gap frequency ratio in the range for the dielectric contrast in the range 11-16 with dielectric spheres of radius with a filling factor of 0.134 and fordielectric contrast of 200 with . A complete gap was not found for the dielectric contrast of 3.9. A complete band gap can be obtained for filling factors for the dielectric contrast in the range with an optimum band gap for the filling factor 0.134 while GaAs () has almost a constant optimum band gap in this range. The largest gap to mid gap ratio of was obtained for GaP (). For dielectric spheres of and larger gap to mid gap ratio were obtained for the dielectric contrast while the largest were obtained for . The only dielectric material BaSrTiO3 () which gives a band gap for the filling factor of 0.4524 can be used in microwave applications.

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31

Ahmad, Javed, Syed Hamad Bukhari, M. Tufiq Jamil, Mehr Khalid Rehmani, Hammad Ahmad, and Tahir Sultan. "Lattice Dynamics and Transport Properties of Multiferroic DyMn2O5." Advances in Condensed Matter Physics 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/5389573.

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We have investigated the optical and electrical properties of polycrystalline DyMn2O5synthesized by sol-gel method. Analysis of the reflectivity spectrum has led to the observation of 18 infrared (IR) active phonon modes out of 36 predicted ones. We discuss the results in terms of different phonon bands originated as a result of atomic vibrations. Moreover, the optical energy band gap ofEg(OC)~1.78 eV has been estimated from optical conductivity(σ1(ω))spectrum. The energy band gap and optical transitions were also determined from UV-visible absorption spectrum and band gap ofEg(UV)~1.57 eV was estimated. Moreover, DC electrical resistivity shows the p-type polaronic conduction above room temperature.

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32

Poklonski, Nikolai A., Sergey A. Vyrko, and Alexander I. Kovalev. "THERMAL ACTIVATION ENERGY OF HOPPING ε2-CONDUCTION VIA BORON ATOMS IN WEAKLY COMPENSATED SILICON." Doklady of the National Academy of Sciences of Belarus 62, no. 4 (September 13, 2018): 406–14. http://dx.doi.org/10.29235/1561-8323-2018-62-4-406-414.

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The insulating side of the concentration insulator–metal phase transition (Mott’s transition) in p-type silicon crystals doped with acceptor (boron atoms) is considered under the conditions of stationary hopping electrical conduction. The boron atoms substitute silicon atoms in the crystal lattice and can be in one of the three charge states (−1, 0, +1), while the compensating impurity (donors) is in the charge state (+1). The distribution of impurity atoms is supposed to be random (Poisson’s distribution). The A0-band is formed from the energy levels of boron atoms in the charge states (0) and (−1), while the A+-band is formed from the energy levels of boron atoms in the charge states (+1) and (0). The decrease in the activation energy ε2 of thermally assisted tunneling transitions (hops) of holes between electrically neutral boron atoms, i. e. boron atoms that are in the charge state (0), is calculated. The ε2 quantity is approximately equal to an energy gap between A0- and A+-bands, i. e. Hubbard’s gap. In the quasi-classical approximation it is shown that the narrowing of the energy gap between A0- and A+-bands occurs due to: (i) the formation of a quasi-continuous band of allowed energy values for v-band holes from excited quantum states of boron atoms in the charge state (0), thus the value of the v-band shift into the band gap is determined by a maximum radius of the hole orbit in a boron atom, which does not exceed the half of the average distance between the nearest impurity atoms, and (ii) the splitting of the ground (non-excited) energy levels of the “molecular” pairs of boron atoms in the charge states (0) into triplet and singlet states of two holes. Calculations of ε2 without any adjustable parameters are quantitatively agree with the known experimental data on p-Si:B.

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33

Abraham, P., M. A. Garcia Perez, T. Benyattou, G. Guillot, M. Sacilotti, and X. Letartre. "Temperature dependence of AlInAs band gap energy and AlInAs/InP band offsets." Materials Science and Technology 14, no. 12 (December 1998): 1291–94. http://dx.doi.org/10.1179/mst.1998.14.12.1291.

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34

Shan, Guang-cun, and Wei Huang. "Energy band and band-gap properties of deformed single-walled silicon nanotubes." Frontiers of Physics in China 5, no. 2 (May 23, 2010): 183–87. http://dx.doi.org/10.1007/s11467-010-0017-7.

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35

Ruan, Xing Xiang, Xian Hui Zhong, Fu Chun Zhang, and Wei Hu Zhang. "Study on Electronic Structure of GaN under Pressure." Advanced Materials Research 900 (February 2014): 217–21. http://dx.doi.org/10.4028/www.scientific.net/amr.900.217.

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A detailed theoretical study of electronic structure and optical properties of GaN under pressure was performed by the first-principles calculations of plane wave ultra-soft pseudo-potential method based on the density functional theory (DFT). The results indicate that Ga-N bond length becomes shorter and the valence bonds shift towards the low energy while the conduction bands towards high energy, the band gap becomes wider with the pressure increasing, and theoretical studies explained the relationship between the band edges, energy gap of GaN and pressure. In addition, the peak in band was cracked slightly, and the Ga 3d-N 2p hybridization was enhanced.

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36

Hossain, Faruque M., Graeme E. Murch, L. Sheppard, and Janusz Nowotny. "The Effect of Defect Disorder on the Electronic Structure of Rutile TiO_2-x." Defect and Diffusion Forum 251-252 (March 2006): 1–12. http://dx.doi.org/10.4028/www.scientific.net/ddf.251-252.1.

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The purpose of this work is to study the effect of bulk point defects on the electronic structure of rutile TiO2. The paper is focused on the effect of oxygen nonstoichiometry in the form of oxygen vacancies, Ti interstitials and Ti vacancies and related defect disorder on the band gap width and on the local energy levels inside the band gap. Ab initio density functional theory is used to calculate the formation energies of such intrinsic defects and to detect the positions of these defect induced energy levels in order to visualize the tendency of forming local mid-gap bands. Apart from the formation energy of the Ti vacancies (where experimental data do not exist) our calculated results of the defect formation energies are in fair agreement with the experimental results and the defect energy levels consistently support the experimental observations. The calculated results indicate that the exact position of defect energy levels depends on the estimated band gap and also the charge state of the point defects of TiO2.

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37

Cahyono, Yoyok, Novita Dwi Purnamasari, Mochamad Zainuri, Suminar Pratapa, and Darminto. "Analysis of Defects and Surface Roughness on the Hydrogenated Amorphous Silicon (a-Si:H) Intrinsic Thin Film for Solar Cells." Materials Science Forum 966 (August 2019): 398–403. http://dx.doi.org/10.4028/www.scientific.net/msf.966.398.

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Effect of defect - through observation of energy absorption Urbach, on deposition rate, energy band gap, and surface roughness of intrinsic thin film are investigated using Radio Frequency Plasma Enhance Chemical Vapor Deposition (RF-PECVD). Films are grown on ITO (Indium Tin Oxide) glass substrate. Analysis of energy band gap is conducted to determine changes in the structure of a thin film of a-Si:H. Energy band gap is important to determine the portion of the spectrum of sunlight that is absorbed solar cells. From the characterization using UV-Vis spectrometer and the Tauc’s plot method, the width of the resulting energy band gap is greater if the hydrogen dilution is increased. It can be shown that the increase of the hydrogen dilution, will increase the energy band gap, and the surface roughness of thin layers. Instead, the improvement of the hydrogen dilution decrease the rate of deposition and Urbach energy. It is estimated that with greater hydrogen dilution, an intrinsic thin film of a-Si:H is more conductive for more reduction in residual of band tail defects or dangling bond defects.

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38

Yang, H. Y., Q. F. Li, and Z. H. Liu. "Electronic and optical properties of 2H-perovskite related tantalum/niobium oxides." Modern Physics Letters B 31, no. 34 (December 6, 2017): 1750323. http://dx.doi.org/10.1142/s0217984917503237.

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Quasi-one-dimensional oxides [Formula: see text] (A = Ba, Sr; [Formula: see text] = Na, Li and B = Ta, Nb) have been synthesized and found to display efficient photoluminescence. Their electronic and optical properties are calculated by using first-principles calculations. The modified Becke–Johnson exchange potential has been used to obtain accurate band gap. Our results reveal that alkali metal and alkaline-earth metal ions have very small contribution to the states around Fermi level, and for these compounds, the top valence bands and the conduction band bottom are dominated by O-2p and Nb/Ta-d states, respectively. All of these compounds have indirect band gap, with valence band maximum at K point and conduction band minimum at [Formula: see text] point. Optical absorption spectrum is characterized by two prominent peaks. The lower energy peak originates from electron transitions between Ta/Nb-[Formula: see text] and O-2p states, while the higher energy peak is determined by electron transitions between Ta/Nb-[Formula: see text] and O-2p. Despite the one-dimensional feature of the lattice structure, the electronic band structure and optical properties show three-dimensional character. We find that the band gap and optical absorption threshold are considerably larger than the energy of excitation light in the luminescence measurement. This indicates the important role of the in-gap states, which may be induced by the impurity or vacancy.

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39

Jayawardana, K. B. S. K. B., and K. A. I. L. Wijewardena Gamalath. "Body Centered Photonic Crystal." International Letters of Chemistry, Physics and Astronomy 66 (May 2016): 96–108. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.66.96.

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The photonic energy bands of body centered cubic photonic crystals formed from SiO2, GaP, Si, InAs, GaAs, InP, Ge and BaSrTiO3 dielectric spheres drilled in air and air holes drilled in these dielectric mediums were calculated using the plane wave expansion method. The filling factor for each dielectric material was changed until a complete energy gap was obtained and then the density of states was calculated. There were no complete band gaps for air spheres drilled in these eight dielectric mediums. The lattice constants were determined by using wavelengths in the region . The variation of the band gap widths with the filling factor and the variation of gap width to midgap frequency ratios with dielectric contrast were investigated. The largest band gap width of 0.021 for normalized frequency was obtained for GaP for the filling factor of 0.0736. The mode filed distributions were obtained by guiding a telecommunication wave with wavelength through a photonic cell formed from GaP spheres in air with a filling factor of 0.0736 for transverse electric and magnetic modes.

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40

Romaka, L. P., Yu V. Stadnyk, V. V. Romaka, P. F. Rogl, V. A. Romaka, and A. M. Horyn. "Investigation of structural, thermodynamic and energy state characteristics of the ZrNi1-xRhxSn solid solution." Фізика і хімія твердого тіла 19, no. 2 (May 2, 2019): 151–58. http://dx.doi.org/10.15330/pcss.19.2.151-158.

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The peculiarities of crystal and electronic structures, thermodynamic and energy state characteristics of the ZrNi1-xRhxSn semiconductive solid solution were investigated. It has been shown that in the ZrNiSn compound simultaneously exist two types of structural defects of the donor nature which generate two donor bands with different ionization energy in the band gap: a) the donor band ɛD1, formed as a result of a partial, up to ~ 1%, occupation of 4a position of Zr atoms by Ni atoms (mechanism of “a priori doping”) and deep donor band ɛD2, formed as a result of partial occupation of the tetrahedral voids by Ni atoms (Vac). The substitution in 4c position of the Ni atoms by Rh ones in ZrNi1-xRhxSn generates structural defects of acceptor nature and creates an impurity acceptor band ɛA in the band gap, which, in addition to the existence of ɛD1 та ɛD2 donor bands, makes semiconductor highly doped and strongly compensated. The obtained results allow to understand the mechanisms of electrical conductivity of thermoelectric materials based on n-ZrNiSn and the ways of conscious optimization of their characteristics for obtaining the maximum efficiency of conversion of thermal energy into electric.

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41

Mannu, Alberto, Maria Enrica Di Pietro, and Andrea Mele. "Band-Gap Energies of Choline Chloride and Triphenylmethylphosphoniumbromide-Based Systems." Molecules 25, no. 7 (March 25, 2020): 1495. http://dx.doi.org/10.3390/molecules25071495.

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UV–VIS spectroscopy analysis of six mixtures containing choline chloride or triphenylmethylphosphonium bromide as the hydrogen bond acceptor (HBA) and different hydrogen bond donors (HBDs, nickel sulphate, imidazole, d-glucose, ethylene glycol, and glycerol) allowed to determine the indirect and direct band-gap energies through the Tauc plot method. Band-gap energies were compared to those relative to known choline chloride-containing deep band-gap systems. The measurements reported here confirmed the tendency of alcohols or Lewis acids to increment band-gap energy when employed as HBDs. Indirect band-gap energy of 3.74 eV was obtained in the case of the triphenylmethylphosphonium bromide/ethylene glycol system, which represents the smallest transition energy ever reported to date for such kind of systems.

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42

Xue Fang-shi. "ENERGY BAND CALCULATION FOR GaAs, GaP AND GaAsxP1-x." Acta Physica Sinica 35, no. 10 (1986): 1315. http://dx.doi.org/10.7498/aps.35.1315.

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43

Poulsen, Felipe, and Thorsten Hansen. "Band Gap Energy of Gradient Core–Shell Quantum Dots." Journal of Physical Chemistry C 121, no. 25 (June 16, 2017): 13655–59. http://dx.doi.org/10.1021/acs.jpcc.7b01792.

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44

Mandal, Sukhendu, Arthur C. Reber, Meichun Qian, Paul S. Weiss, Shiv N. Khanna, and Ayusman Sen. "Controlling the Band Gap Energy of Cluster-Assembled Materials." Accounts of Chemical Research 46, no. 11 (June 4, 2013): 2385–95. http://dx.doi.org/10.1021/ar3002975.

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45

Yang, Shujiang, and Miklos Kertesz. "Bond Length Alternation and Energy Band Gap of Polyyne." Journal of Physical Chemistry A 110, no. 31 (August 2006): 9771–74. http://dx.doi.org/10.1021/jp062701+.

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46

de Dios Leyva, M., and J. López Gondar. "Zero Energy Gap Conditions and Band Inversion in Superlattices." physica status solidi (b) 128, no. 2 (April 1, 1985): 575–81. http://dx.doi.org/10.1002/pssb.2221280223.

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47

Sentosa, D., X. Tang, and S. J. Chua. "InNxAs1-xband gap energy and band bowing coefficient calculation." European Physical Journal Applied Physics 40, no. 3 (December 2007): 247–51. http://dx.doi.org/10.1051/epjap:2007157.

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48

Shanshool, Haider Mohammed, Muhammad Yahaya, Wan Mahmood Mat Yunus, and Ibtisam Yahya Abdullah. "Investigation of energy band gap in polymer/ZnO nanocomposites." Journal of Materials Science: Materials in Electronics 27, no. 9 (May 31, 2016): 9804–11. http://dx.doi.org/10.1007/s10854-016-5046-8.

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49

Boukhatem, M. H. "Carriers Temperature Dependence of Energy Band Gap for Germanium." Silicon 8, no. 2 (December 18, 2015): 309–12. http://dx.doi.org/10.1007/s12633-015-9361-0.

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50

Kitamura, Noboru, Hidetsugu Yamamoto, and Takao Wada. "Temperature dependence of band-gap energy of AlxGa1−xSb." Materials Letters 15, no. 1-2 (October 1992): 89–91. http://dx.doi.org/10.1016/0167-577x(92)90018-f.

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