scholarly journals Зонная структура и процессы в электронной системе кристаллов (Bi-=SUB=-2-x-=/SUB=-Sb-=SUB=-x-=/SUB=-)Te-=SUB=-3-=/SUB=- (0<x<2) по данным оптических исследований в инфракрасном диапазоне

2021 ◽  
Vol 55 (7) ◽  
pp. 586
Author(s):  
Н.П. Степанов ◽  
А.А. Калашников ◽  
О.Н. Урюпин
Keyword(s):  
Band Gap ◽  
Effective Mass ◽  
Temperature Change ◽  
Optical Band Gap ◽  
Charge Carriers ◽  
Reflection Spectra ◽  
Free Charge ◽  
Plasma Oscillations ◽  
Increasing Temperature ◽  
P Type

The decrease in the resonance frequency of plasma oscillations of free charge carriers omegap with increasing temperature observed in Bi2-xSbx (0 <x <2) p-type crystals can only be partially explained by an increase in the polarization background of the crystal ε-infinity. Analysis of the experimental data suggests that the temperature change in omegap observed in the range from 80 to 300 K is also due to a decrease in the ratio of the concentration of free charge carriers to their effective mass p / m *. This can be explained by an increase in the effective mass of carriers with increasing temperature, as well as by the process of hole redistribution between nonequivalent extrema of the valence band, the existence of which is confirmed by the regularities of the temperature change in the optical band gap observed in the reflection spectra of infrared radiation. Key words: semiconductors, plasma resonance, concentration, effective mass of free charge carriers, electrical conductivity, thermal and optical band gap.

scholarly journals Закономерности температурных изменений спектров отражения инфракрасного излучения кристалла Bi-=SUB=-0.8-=/SUB=-Sb-=SUB=-1.2-=/SUB=-Te-=SUB=-3-=/SUB=- в области возбуждения плазменнных колебаний свободных носителей заряда и межзонных переходов

2021 ◽  
Vol 129 (5) ◽  
pp. 619
Author(s):  
Н.П. Степанов ◽  
А.А. Калашников
Keyword(s):  
Absorption Edge ◽  
Optical Band Gap ◽  
Fundamental Absorption Edge ◽  
Charge Carriers ◽  
Reflection Spectra ◽  
Free Charge ◽  
Plasmon Energy ◽  
Plasma Oscillations ◽  
Increasing Temperature ◽  
Plasmon Interaction

The regularities of the temperature behavior of the reflection spectra of the Bi0.8Sb1.2Te3 crystal obtained in the range of the plasma resonance of free charge carriers and the fundamental absorption edge allow us to trace the changes in the plasmon energy Ep and the optical band gap Eg opt. The observed decrease in Eg opt with increasing temperature corresponds to the existing ideas about the redistribution of holes between the nonequivalent extremes of the valence band in (Bi2-xSbx)Te3 (0<x<1) crystals. The dominance of this process in a certain temperature range contributes to the change in plasma frequencies. Keywords: reflection spectra, plasma oscillations, electron-plasmon interaction, dielectric functions.

scholarly journals Edge Absorption of thin Films –Ga2O3

2015 ◽  
Vol 16 (2) ◽  
pp. 302-306
Author(s):  
O.M. Bordun ◽  
B.O. Bordun ◽  
V.B. Lushchanets ◽  
I.Yo. Kukharskyy
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Absorption Edge ◽  
Optical Band Gap ◽  
Fundamental Absorption Edge ◽  
Hydrogen Atmosphere ◽  
Argon Atmosphere ◽  
Charge Carriers ◽  
Free Charge ◽  
Moss Effect

Fundamental absorption edge of b–Ga2O3 thin films, obtained by radio-frequency ion-plasmous sputtering, was investigated, using the method of optical spectroscopy. It was ascertained that the optical band gap Eg increases from 4.60 to 4.65 eV after the heat treatment films in argon atmosphere and to 5.20 eV after the reduction of annealed films in a hydrogen atmosphere. Consolidated effective mass of free charge carriers in b–Ga2O3 films after annealing and after reduction in hydrogen was estimated. It was found that the concentration of charge carriers after heat treatment in argon atmosphere is 7.30´1017 cm–3 and after reduction in hydrogen, is 2.62´1019 cm–3, which is typical for degenerated semiconductors. It was shown that the shift of fundamental absorption edge in thin films b–Ga2O3 after reduction in hydrogen is caused by Burstein-Moss effect.

Absorber Films of Antimony Chalcogenides via Chemical Deposition for Photovoltaic Application

2004 ◽  
Vol 836 ◽  
Author(s):  
M. T. S. Nair ◽  
Y. Rodríguez-Lazcano ◽  
Y. Peña ◽  
S. Messina ◽  
J. Campos ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Chemical Deposition ◽  
Dark Conductivity ◽  
Glass Substrates ◽  
Photovoltaic Application ◽  
Sodium Selenosulfate ◽  
P Type ◽  
Antimony Chalcogenides

ABSTRACTAntimony sulfide thin films (300 nm) have been deposited on glass substrates at 1–10°C from chemical bath. When heated these become crystalline and photoconductive with optical band gap (direct) of 1.7 eV. Thin films formed from chemical baths containing SbCl3 and sodium selenosulfate are of mixed phase Sb2O3/Sb2Se3, which when heated in the presence of Se-vapor converts to single phase Sb2Se3 film with optical band gap of 1.1 eV. Such films possess dark conductivity of 10-8 ohm-1cm-1 and show photosensitivity of two orders. Reaction of Sb2S3-CuS in nitrogen at 400°C produces crystalline, photoconductive p-type CuSbS2 with optical band gap (direct) of 1.5 eV. By controlling the deposition and heating condition, (i)Sb2S3-(p)CuSbS2 layer is formed, which is utilized in a photovoltaic structure, (n)CdS:In-(i)Sb2S3-(p)CuSbS2, with a Voc of 345 mV and Jsc 0.18 mA/cm2 under 1 kW m-2 tungsten halogen illumination. In the case of a structure, CdS:Cl-Sb2S3-Cu2-xSe, Voc of 350 mV and Jsc of 0.5 mA/cm2 are observed.

scholarly journals Effects of Sintering Atmosphere on the Optical, Thermal and Electrical Properties of Inkjet Printed ZnxCu(1-x)Fe2O4 Thin Films

2021 ◽  
Vol 81 (2) ◽  
pp. 25-35
Author(s):  
Lim Joon Hoong
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Band Gap ◽  
Optical Band Gap ◽  
Electronic Band Structure ◽  
Copper Ferrite ◽  
Electronic Band ◽  
Sintering Atmosphere ◽  
P Type

The effects of sintering atmosphere on the optical, thermal and electric properties of inkjet printed ZnxCu(1-x)Fe2O4 thin films have been investigated. The thin film samples were sintered separately in vacuum and oxygen. The obtained samples were then characterized by X-ray diffraction (XRD), optical band gap, electrical conductivity, Seebeck coefficient and thermal conductivity. XRD analysis showed that the fabricated samples have a cubic spinel structure of zinc copper ferrite regardless of the sintering atmosphere. The electrical conductivity of ZnxCu(1-x)Fe2O4 thin films sintered in oxygen was about 5 % higher compared to ZnxCu(1-x)Fe2O4 thin films sintered in vacuum. The optical band gap shows that the samples sintered in oxygen had smaller band gap compared to samples sintered in vacuum. The electronic band structure simulated through ABINIT shows ZnxCu(1-x)Fe2O4 is an indirect band gap material. A smaller electronic band gap was observed in O2 rich condition and was in agreement with the optical band gap and electrical conductivity test results. Seebeck coefficient of ZnxCu(1-x)Fe2O4 thin films sintered in oxygen remained positive , confirming charge transport by hole carries as p-type semiconductors. A change from p-type to n-type semiconductors was observed when ZnxCu(1-x)Fe2O4 thin films sintered in vacuum.

Valency control of P-type a-SiC:H having the optical band gap more than 2.5 eV by electron-cyclotron resonance CVD (ECR CVD)

1987 ◽  
Vol 97-98 ◽  
pp. 1079-1082 ◽  
Author(s):  
Yutaka Hattori ◽  
Dusit Kruangam ◽  
Toshihiko Toyama ◽  
Hiroaki Okamoto ◽  
Yoshihiro Hamakawa
Keyword(s):  
Band Gap ◽  
Cyclotron Resonance ◽  
Optical Band Gap ◽  
Electron Cyclotron Resonance ◽  
Type A ◽  
Electron Cyclotron ◽  
P Type

p-Type electrical conduction and wide optical band gap in Mg-doped CuAlS2

2008 ◽  
Vol 58 (11) ◽  
pp. 1002-1005 ◽  
Author(s):  
Min-Ling Liu ◽  
Fu-Qiang Huang ◽  
Li-Dong Chen
Keyword(s):  
Band Gap ◽  
Electrical Conduction ◽  
Optical Band Gap ◽  
P Type ◽  
Mg Doped

scholarly journals Thermoelectric properties of Sn-doped p-type Cu3SbSe4: a compound with large effective mass and small band gap

2014 ◽  
Vol 2 (33) ◽  
pp. 13527-13533 ◽  
Author(s):  
Tian-Ran Wei ◽  
Heng Wang ◽  
Zachary M. Gibbs ◽  
Chao-Feng Wu ◽  
G. Jeffrey Snyder ◽  
...  
Keyword(s):  
Band Structure ◽  
Band Gap ◽  
Effective Mass ◽  
Thermoelectric Properties ◽  
Deformation Potential ◽  
Small Band ◽  
P Type

Sn-doped Cu3SbSe4 with enhanced zT possesses a large effective mass, small band gap and moderate deformation potential with a complex band structure.

THE INFLUENCE OF CARBON AND BORON ATOMS ON THE OPTICAL AND ELECTRICAL PROPERTIES OF THIN FILM a-Si:H

2006 ◽  
Vol 20 (25) ◽  
pp. 1591-1596 ◽  
Author(s):  
ISIK KARABAY
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Window Layer ◽  
Optical And Electrical Properties ◽  
Research Plan ◽  
P Type ◽  
Gas Ratio ◽  
Made In

A series of undoped and p-doped a-SiC:H samples have been made in the framework of a research plan for obtaining high quality p-type window layers by "Plasma Enhanced Chemical Vapor Deposition (PECVD)" technique from the mixtures of silane ( SiH 4), methane ( CH 4) and diborane ( B 2 H 6) gases. For the optimization of the window layer, the dependence of the electrical (conductivity) and optical (band gap) properties due to altered ratios of methane and diborane gases were investigated. When the diborane gas ratio was changed from Y = 0.06 to Y = 0.24 with an increase of 0.06 steps at a constant of X = 0.948 methane gas ratio, the dark conductivity and optical band gap values changed from ~ 10-19 (Ω· cm )-1 to ~ 10-10 (Ω· cm )-1 and 2.542 eV to 2.178 eV, respectively, and between these values, the most appropriate layers can be selected.

Highly Conductive and Wide Band GaP Microcrystalline Silicon Films Prepared by Photochemical Vapor Deposition and Applications to Devices

1985 ◽  
Vol 49 ◽  
Author(s):  
S. Nishida ◽  
H. Tasaki ◽  
M. Konagai ◽  
K. Takahashi
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Wide Band ◽  
Dark Conductivity ◽  
Hydrogen Gas ◽  
Microcrystalline Silicon ◽  
Wide Band Gap ◽  
Wide Gap ◽  
P Type ◽  
Photochemical Vapor Deposition

AbstractDoped hydrogenated microcrystalline silicon (μc-Si:H) and fluorinated hydrogenated microcrystalline (μc-Si:F:H) films were prepared by the mercury photosensitized decomposition of a disilane-hydrogen or a difluorosilane-hydrogen gas mixture, respectively. The maximum dark conductivity and optical band gap of μc-Si:H films were respectively 20 S•cm−1 and ∼2.0 eV for n-type and 1 S•cm−1 and 2.3 eV for p-type. A higher dark conductivity as much as 50 S•cm−1 and a wide gap of 2.0 eV were obtained for n-type μc-Si:F:H. It is most significant that the gaseous ratio of hydrogen to disilane should be enhanced to obtain such a highly conductive and wide gap film. The crystallinity of the photo-deposited μc-Si:H films appeared to be improved in comparison with that of films by the conventional plasma glow discharge technique.

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