Estimation of Density of Defect States from A.C. Conductivity Measurement in Glassy Alloys of Se90In10–xAgx

2016 ◽  
Vol 5 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Suresh Kumar Sharma ◽  
R. K. Shukla ◽  
A. Kumar
Keyword(s):  
Conductivity Measurement ◽  
Defect States ◽  
Glassy Alloys ◽  
Density Of Defect States

ELECTRICAL AND PHOTOELECTRICAL PROPERTIES OF A-Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) THIN FILMS

2013 ◽  
Vol 22 ◽  
pp. 439-451
Author(s):  
AMBIKA SHARMA ◽  
KUMARI ANSHU ◽  
PREETI YADAV
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Life Time ◽  
Defect States ◽  
Temperature Dependent ◽  
Photoelectrical Properties ◽  
Glassy Alloys ◽  
Localized State ◽  
Evaporation Technique ◽  
Density Of Defect States

Bulk samples of Te-rich Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) glassy alloys are prepared by melt quenching technique. The thin films of the bulk samples are deposited by using vacuum evaporation technique for their electrical and photoelectrical measurements. Keithley 6487 picoammeter has been used to study the electrical and photoelectrical characteristics of Ge20Te80-XBix thin films kept in vacuum. Temperature dependent dark and photoconductivity is studied in the temperature range 300-360 K and voltage V = 80V. Photoconductivity with intensity at room temperature follows a power law where power γ lies near to 0.5, suggesting that the recombination is bimolecular in nature. The density of defect states and photosensitivity are found to follow an opposite trend with each other. The differential life time is determined from the rise and decay of photocurrent w.r.t. time. The dispersion parameter and localized state distribution parameter are estimated from decay curves and reported for the studied composition.

ITO/a-SiNx:H/a-Si:H Photodiode with Enhanced Photosensitivity and Reduced Leakage Current Using Polycrystalline ITO Deposited at Room Temperature

2000 ◽  
Vol 609 ◽  
Author(s):  
S. Tao ◽  
Q. Ma ◽  
D. Striakhilev ◽  
A. Nathan
Keyword(s):  
Leakage Current ◽  
Dark Current ◽  
Room Temperature ◽  
Dynamic Range ◽  
Transport Model ◽  
Measurement Data ◽  
Mis Structure ◽  
Defect States ◽  
Large Area ◽  
Density Of Defect States

ABSTRACTWe report an ITO/a-SiNx:H/a-Si:H MIS photodiode structure based on room temperature deposition of optically transparent polycrystalline ITO for applications in large area optical and x-ray imaging. The photodiode structure exhibits device characteristics with reduced leakage current and enhanced photosensitivity giving rise to a hundred-fold improvement in dynamic range. This notable improvement in performance is believed to be due to the reduced diffusion of oxygen from the ITO to the a-Si:H layer, and thus reducing the density of defect states inside the a-Si:H layer. The behavior of photo and dark current is consistent with an elaborate transport model for the Schottky barrier. The model agrees reasonably well with measurement data for the dark current and provides a consistent picture in terms of the photo current behavior in the MIS structure, where the insulating layer serves to reduce the oxygen diffusion.

Formation, Structure and Optical Properties of Nanocrystalline BaSi2 Films on Si(111) Substrate

2015 ◽  
Vol 245 ◽  
pp. 42-48 ◽  
Author(s):  
Dmitrii Vladimirovich Fomin ◽  
Victor Leonidovich Dubov ◽  
Konstantin Nickolaevich Galkin ◽  
Dmitrii L'vovich Goroshko ◽  
Andrei Mikhailovich Maslov ◽  
...  
Keyword(s):  
Solid Phase ◽  
Interband Transition ◽  
Grazing Incidence ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Defect States ◽  
Force Microscopy ◽  
Atomic Force ◽  
Density Of Defect States ◽  
Anneal Temperature

BaSi2 thin films were formed on Si (111) substrate by solid-phase epitaxy (SPE) (UHV deposition) using the template technology followed by vacuum annealing at temperatures of 600 °C and 750 °C. After the deposition and annealing barium silicide films were characterized by Auger electron spectroscopy, grazing incidence x-ray diffraction (GIXRD) and atomic-force microscopy (AFM). It was established that the films annealed at T = 600 °C are polycrystalline with the structure of the orthorhombic BaSi2, with grain sizes of 100-200 nm. Higher anneal temperature (T=750 °C) leads to increase of diffraction peak intensity of BaSi2 phase with grain coagulation into 300-400 nm islands. It was confirmed that nanocrystalline BaSi2 films are characterized by a direct fundamental interband transition at 1.3 eV, the second interband transition with an energy of 2.0 eV, own phonon structure with wave number peaks at 112, 119, 146 and 208 cm-1 and a high density of defect states within the band gap, which provide a noticeable subband absorption at energies of 0.8 – 1.1 eV.

The Peculiar Role of the Third Element Indium in Density of Defect States of Se90Ge10 Thin Films

2017 ◽  
Vol 6 (4) ◽  
pp. 424-427
Author(s):  
R. Mishra ◽  
Anjani Kumar ◽  
D. Kumar ◽  
S. Shukla ◽  
R. K. Shukla
Keyword(s):  
Thin Films ◽  
Defect States ◽  
The Third ◽  
Density Of Defect States

Mechanism of Trapping Effect in Heterojunction With Intrinsic Thin-Layer Solar Cells: Effect of Density of Defect States

2012 ◽  
Vol 59 (5) ◽  
pp. 1227-1235 ◽  
Author(s):  
X. Hua ◽  
Z. P. Li ◽  
W. Z. Shen ◽  
G. Y. Xiong ◽  
X. S. Wang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Thin Layer ◽  
Defect States ◽  
Trapping Effect ◽  
Density Of Defect States

A comparative study of the density of defect states in bulk samples and thin films of glassy Se90Sb10

Pramana ◽  
2016 ◽  
Vol 86 (5) ◽  
pp. 1099-1105 ◽  
Author(s):  
ANJANI KUMAR ◽  
PRABHAT K DWIVEDI ◽  
R K SHUKLA ◽  
A KUMAR
Keyword(s):  
Thin Films ◽  
Comparative Study ◽  
Defect States ◽  
Density Of Defect States

Toward a Practical Model of a-Si:H Defects in Intensity-Time-Temperature Space

1994 ◽  
Vol 336 ◽  
Author(s):  
D. Caputo ◽  
J. Bullock ◽  
H. Gleskova ◽  
S. Wagner
Keyword(s):  
Light Intensity ◽  
Fermi Level ◽  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Hydrogenated Amorphous Silicon ◽  
Defect States ◽  
Quasi Fermi Level ◽  
Practical Model ◽  
Density Of Defect States ◽  
Hydrogenated Amorphous

ABSTRACTIn this paper we develop a model of the defect kinetics in hydrogenated Amorphous silicon (a:Si:H) with the goal of predicting the density of defect states g (E) established by any given light intensity I, for arbitrary times t and temperatures T. While we build on widely accepted expressions for the the rates of light-induced and thermal annealing, we examine in more detail the light induced annealing (LIA) term. The model shows that the LIA process can be described with the thermal annealing term if a suitable reduction to the annealing energy is introduced. This reduction depends on the light intensity such as to suggest a relation to the shift of the electron quasi-Fermi level under illumination.

scholarly journals Capacitance Analysis of the Structures with the a-Si:H(i)/c-Si(p) Heterojunction for Solar-Cell Applications

2014 ◽  
Vol 65 (4) ◽  
pp. 254-258 ◽  
Author(s):  
Miroslav Mikolášek ◽  
Ján Jakaboviš ◽  
Vlastimil Řeháček ◽  
Ladislav Harmatha ◽  
Robert Andok
Keyword(s):  
Solar Cell ◽  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Amorphous Layer ◽  
Band Offset ◽  
Defect States ◽  
Conduction Band Offset ◽  
Silicon Heterojunction Solar Cell ◽  
Density Of Defect States ◽  
Passivated Silicon

Abstract In this paper we present the capacitance study of the intrinsic amorphous silicon/crystalline silicon heterostructure with the aim to gain insight on the heterointerface properties of a passivated silicon heterojunction solar cell. It is shown that due to the high density of defect states in the amorphous layer the structure has to be analyzed as a heterojunction. Using the analysis, the following values have been determined: conduction-band offset of 0.13 eV, electron affinity of 3.92 eV, and density of defect states in the intrinsic amorphous silicon being that of 4.14 X 1021m—3.

scholarly journals Density of Defect States and Spectra of Defect Absorption in a-Si:H

2019 ◽  
Vol 64 (4) ◽  
pp. 315
Author(s):  
R. G. Ikramov ◽  
M. A. Nuriddinova ◽  
R. M. Jalalov
Keyword(s):  
Absorption Coefficient ◽  
Density Of States ◽  
Spectral Characteristics ◽  
Localized States ◽  
Defect States ◽  
Hydrogenated Silicon ◽  
Principal Role ◽  
Electron Transitions ◽  
Amorphous Hydrogenated Silicon ◽  
Density Of Defect States

Spectral characteristics of the coefficient of defect absorption in amorphous hydrogenated silicon have been studied. The characteristics are determined, by analyzing the electron transitions occurring with the participation of the energy states of dangling bonds. It is shown that the principal role in the formation of the defect absorption coefficient value is played by the electron transitions between defect and non-localized states. It is also shown that the spectral characteristics are mainly determined by the distribution function of the electron density of states in the valence or conduction band. It is found that the maxima in the spectrum of the defect absorption coefficient are observed only if there are pronounced maxima in the density of states at the edges of allowed bands.

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