Ion Irradiated Amorphous Silicon: A Model Approach to Dynamics of Defect Creation and Annihilation

1993 ◽  
Vol 311 ◽  
Author(s):  
Jung H. Shin ◽  
Harry A. Atwater
Keyword(s):  
Activation Energy ◽  
Energy Spectrum ◽  
Amorphous Silicon ◽  
Quantitative Agreement ◽  
Defect States ◽  
Experimental Activation Energy ◽  
Density Of Defect States ◽  
First Time ◽  
Recombination Kinetics ◽  
Model Approach

ABSTRACTThe dynamics of defect annihilation and creation in amorphous silicon (a-Si) are measured in detail using defect-related changes in the electrical conductivity of a-Si A model is proposed which for the first time can track the complete time evolution of defect population across the activation energy spectrum with explicit dependence on irradiation and annealing parameters. The model is based upon experimental activation energy spectrum, bimolecular recombination kinetics, and on the notion of a maximum density of defect states beyond which no additional defects can be supported. The new model predicts transient dynamics in defect population and describes structure of the defect population in detail. Its predictions are in good qualitative agreement, and in reasonable quantitative agreement with experimental data.

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.

Improvement in the Transport of Charge Carriers in Tunnel Junctions of Silicon-Based Thin Film Tandem Solar Cells

2012 ◽  
Vol 159 ◽  
pp. 137-140
Author(s):  
Ming Ji Shi ◽  
Xin Feng Guo ◽  
Sheng Zhao Wang ◽  
Lan Li Chen
Keyword(s):  
Activation Energy ◽  
Solar Cells ◽  
Tunnel Junction ◽  
Deposition Process ◽  
Defect States ◽  
Recombination Rates ◽  
Tandem Solar Cells ◽  
Current Voltage ◽  
Density Of Defect States ◽  
Silicon Based

We report new results on a tunneling junction for tandem solar cells using a nano-structured amorphous silicon p+layer (na-Si p+) as the recombination layer inserted between the n layer and the p layer. Devices were characterized by their dark current-voltage behavior (I-V), activation energy (Ea) and quantum efficiency (QE). The result shows that the tunnel junction with a na-Si p+insertion layer has higher recombination rates with higher density of defect states of about 2.7×1019cm-3, lower resistance with activation energy of 22meV. The tunnel junction with a na-Si p+insertion layer could be easily integrated into the tandem solar cell deposition process.

Amorphous Silicon Thin Film Transistors and Memory Devices

1985 ◽  
Vol 49 ◽  
Author(s):  
P.G. Lecomber
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Field Effect Transistors ◽  
Memory Devices ◽  
Preparation Technique ◽  
Defect States ◽  
Large Area ◽  
Silicon Thin Film ◽  
Simple Logic ◽  
Density Of Defect States

AbstractThe preparation of amorphous silicon with a low density of defect states by the glow discharge decomposition of silane and the ability to control its electrical conductivity over many orders of magnitude by the addition of phosphine or diborane to the silane, stimulated a worldwide interest in this material and in its possible applications. This paper begins with a description of the preparation technique and a brief review of some of the important properties of the material. The fabrication and characteristics of a-Si thin-film field effect transistors will be described and followed by a discussion of the applications of these devices in large area liquid crystal displays, in simple logic circuits and in addressable image sensors. Finally, the use of a-Si in memory devices will be briefly described.

Good Quality N (a-Si)-P+(Na-Si)-P (μC-Si) Tunnel Junction for Tandem Solar Cells

2011 ◽  
Vol 181-182 ◽  
pp. 336-339
Author(s):  
Lan Li Chen ◽  
Ming Ji Shi ◽  
Jia Hui Yu
Keyword(s):  
Activation Energy ◽  
Solar Cells ◽  
Tunnel Junction ◽  
Deposition Process ◽  
Defect States ◽  
Recombination Rates ◽  
Tandem Solar Cells ◽  
Current Voltage ◽  
Density Of Defect States ◽  
Recombination Junction

A new tunnel-recombination junction model was proposed to increase the recombination of n/p junctions in tandem solar cells. According to the model, we fabricated a new tunnel junction with a nanostructured amorphous silicon p+(na-Si p+) layer inserted between the n layer and the p layer. To compare with the conventional method, we fabricated another tunnel junction with an amorphous p+(a-Si p+) insertion layer. Both devices were characterized by their dark current-voltage behavior (I-V), activation energy (Ea) and quantum efficiency (QE). The result shows that the tunnel junction with a na-Si p+insertion layer has higher recombination rates with higher density of defect states of about 2.7×1019cm-3, lower resistance with activation energy of 22meV. The tunnel junction with a na-Si p+insertion layer could be easily integrated into the tandem solar cell deposition process.

The Instability Characteristics of Amorphous Silicon Thin Film Transistors with Various Interfacial and Bulk Defect States

1997 ◽  
Vol 36 (Part 1, No. 10) ◽  
pp. 6226-6229 ◽  
Author(s):  
Huang-Chung Cheng ◽  
Jun-Wei Tsai ◽  
Chun-Yao Huang ◽  
Fang-Chen Luo ◽  
Hsing-Chien Tuan
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Defect States ◽  
Silicon Thin Film

Deposition and Crystallisation Behaviour of Amorphous Silicon Thin Films Obtained by Pyrolysis of Disilane Gas at Very Low Pressure

1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Electrical Conductance ◽  
Chemical Vapor ◽  
Crystalline Fraction ◽  
Silicon Thin Films ◽  
Crystallisation Behaviour

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.

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