Hydrogen Dynamics in a-Si:H

1993 ◽  
Vol 297 ◽  
Author(s):  
Paulo V. Santos
Keyword(s):  
Carrier Concentration ◽  
Thermal Equilibrium ◽  
Carrier Density ◽  
Reverse Bias ◽  
Diffusion Path ◽  
Dissociation Rate ◽  
Effective Density ◽  
Hydrogen Migration ◽  
Carrier Population

The interaction between electronic carriers and hydrogen migration in a-Si:H was investigated by diffusion experiments in the intrinsic (i−) layer of p-i-n a-Si:H photo-diodes. The carrier concentration in the i-layer was controlled by varying the bias applied to the devices. Hydrogen migration (i) is enhanced when the carrier population is increased by illumination and (ii) is suppressed when it is reduced below the thermal equilibrium value by the application of a reverse bias to the diodes. The effect is attributed to the dependence on carrier density of the dissociation rate of hydrogen from Si-H bonds into the diffusion path consisting of interstitial sites. In addition, the migration length in the diffusion path increases under reverse bias. The enhanced migration is associated with a decrease in the effective density of traps for hydrogen in a carrier-depleted layer. Possible mechanisms for the interaction between hydrogen migration, carriers and defects are discussed.

Enhancement of Intrinsic Carrier Concentration in the Active Layer of Solar Cell Using Indium Nitride Quantum Dot

2015 ◽  
Vol 793 ◽  
pp. 435-439 ◽  
Author(s):  
M.A. Humayun ◽  
M.A. Rashid ◽  
F. Malek ◽  
S.B. Yaakob ◽  
A.Z. Abdullah ◽  
...  
Keyword(s):  
Solar Cell ◽  
Quantum Dot ◽  
Carrier Concentration ◽  
Density Of States ◽  
Active Layer ◽  
Cell Structure ◽  
Indium Nitride ◽  
Effective Density ◽  
Intrinsic Carrier Concentration ◽  
Solar Cell Structure

This paper presents the improvement of intrinsic carrier concentrations in the active layer of solar cell structure using Indium Nitride quantum dot as the active layer material. We have analyzed effective density of states in conduction band and valance band of the solar cell numerically using Si, Ge and InN quantum dot in the active layer of the solar cell structure in order to improve the intrinsic carrier concentration within the active layer of the solar cell. Then obtained numerical results were compared. From the comparison results it has been revealed that the application of InN quantum dot in the active layer of the device structure improves the effective density of states both in conduction band and in the valance band. Consiquently the intrinsic carrier concentration has been improved significently by using InN quantum dot in the solart cell structure.

Field Drift Of Plasma-Induced Defects In Phosphorus Doped Si By Reverse Bias Annealing (RBA)

1996 ◽  
Vol 442 ◽  
Author(s):  
J. Takeuchi ◽  
Y. Zaitsu ◽  
T. Shimizu ◽  
S. Matsumoto ◽  
K. Wada
Keyword(s):  
Reverse Bias ◽  
Arrhenius Plot ◽  
Thermal Dissociation ◽  
Dissociation Rate ◽  
Plasma Exposure ◽  
Defect Complexes ◽  
Induced Defects ◽  
Phosphorus Doped ◽  
Charged Defects ◽  
Field Drift

AbstractThe property of plasma induced defects in phosphorus doped CZ silicon has been investigated by reverse bias annealing (RBA). After CF4 plasma exposure, charge density at the surface decreased since plasma induced negatively charged defects inactivated phosphorus. With the increase of annealing time, inactivated phosphorus area moved into the bulk with reverse bias of −3V. Thus it is clearly observed that negatively charged defects drifted from the surface into the bulk. The thermal dissociation energy for phosphorus-defect complexes is estimated to be 1.22eV from the Arrhenius plot of dissociation rate. These defects are likely to be Si self interstitials or vacancies.

Temperature Variation Effects on Current-Voltage (i-v) Characteristics of n-GaN Schottky Diode

2006 ◽  
Vol 517 ◽  
pp. 141-146
Author(s):  
Tarriq Munir ◽  
Azlan Abdul Aziz ◽  
Mat Johar Abdullah ◽  
Naser Mahmoud Ahmed
Keyword(s):  
Low Temperature ◽  
Carrier Concentration ◽  
Temperature Variation ◽  
Schottky Diode ◽  
Reverse Bias ◽  
Pt Electrode ◽  
Turn On ◽  
Bandgap Narrowing ◽  
Current Voltage ◽  
Higher Temperature

We focus in this paper the temperature variation effects on the current – voltage ( I-V) characteristics of n-GaN schottky diode. The diode was doped with carrier concentration 1*1013cm-3 and Pt electrode was used. The simulated current were obtained at temperatures from 50K to 500K and voltage up to 2Volt. We use the Srh (Schokley read hall), Cvt (Lombardi Model), Auger (Auger), Fermi (Fermi Dirac), Impact, Bgn (Bandgap Narrowing), Complete ioniz model to get the schottky rectifying current – voltage (I-V) characteristics.. We find that by increasing the temperature from 50K to 500K, the forward schottky rectifying current decreases from 2.7187 Amp to 0.383 Amp. while the forward turn – on voltage decreases. In reverse bias at low temperature the current is high and we increase the temperature the current decreases. The breakdown voltage decreases at higher temperature.

A Comparative Study of Confined Carrier Concentration of Laser Using Quantum well and Quantum Dot in Active Layer

2013 ◽  
Vol 701 ◽  
pp. 188-191 ◽  
Author(s):  
M.A. Humayun ◽  
M.A. Rashid ◽  
F. Malek ◽  
A. Yusof ◽  
F.S. Abdullah ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Quantum Dot ◽  
Quantum Well ◽  
Comparative Study ◽  
Carrier Concentration ◽  
Active Layer ◽  
Carrier Density ◽  
Gain Medium ◽  
Device Structure ◽  
Comparison Results

This paper presents a comparative analysis of some of the important characteristics of the carriers of quantum well and quantum dot based laser. Among the characteristics of the carriers, confined carrier concentrations in the gain medium as well as the carrier concentrations at the threshold have been studied extensively by using InxGa1-xN based quantum well and InxGa1-xN based quantum dot in the active layer of the laser structure. The numerical results obtained are compared to investigate the superiority of the quantum dot over quantum well. It is ascertained from the comparison results that InxGa1-xN based quantum dot provides higher density of confined carrier and lower level of carrier concentration required for lasing action. This paper reports the enhancement of confined carrier density and minimization of carrier concentration at threshold of laser using InxGa1-xN based quantum dot as the active layer material. Hence, it is revealed that better performances of lasers have been obtained using InxGa1-xN based quantum dot than that of quantum well in the active medium of the device structure.

Thermoelectric Properties of Undoped and Si-doped Bulk GaN

2013 ◽  
Vol 1558 ◽  
Author(s):  
Baozhu Wang ◽  
Bahadir Kucukgok ◽  
Qinyue He ◽  
Andrew G. Melton ◽  
Jacob Leach ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
High Power ◽  
Carrier Density ◽  
Doping Concentration ◽  
Seebeck Coefficients ◽  
High Power Factor ◽  
Bulk Gan ◽  
Si Doped

ABSTRACTIn this study, thermoelectric properties of bulk and epitaxy GaN with various doping concentration are investigated. Seebeck coefficients decreased with the increase of carrier concentration for both bulk and epitaxial GaN samples, and the Seebeck coefficients of epitaxial GaN samples are found to be larger than that of bulk GaN samples in the similar carrier density due to the higher dislocation scattering. For epitaxial samples, a high power factor of 4.72 × 10-4 W/m-K2 is observed. The power factors of the bulk GaN samples are in the range of from 0.315× 10-4W/m-K2 to 0.354× 10-4W/m-K2 due to the low Seebeck coefficients.

Amplitude Dependence of Metastable Defect Formation

1993 ◽  
Vol 297 ◽  
Author(s):  
W.B. Jackson ◽  
C. Nebel ◽  
R.A. Street
Keyword(s):  
Rate Constants ◽  
Thermal Equilibrium ◽  
Carrier Density ◽  
Defect Formation ◽  
Amplitude Dependence ◽  
Single Variable ◽  
Thermally Induced ◽  
Microscopic Models ◽  
Kinetics Of ◽  
Metastable Defect

The kinetics of small changes from thermal equilibrium are measured and simulated for thermally induced metastable changes. We find that only a distribution of rate constants is consistent with the data, and therefore we can eliminate certain types of microscopic models for metastability which depend on a single variable such as the carrier density.

Deep Trap Concentrations from Three-Dimensional Carrier Concentration Profiles in Hydride Vapor Pressure Epitaxially-Grown GaN

2006 ◽  
Vol 251-252 ◽  
pp. 35-50
Author(s):  
N.C. Halder ◽  
J. Martin ◽  
D. Sisler Jr.
Keyword(s):  
Vapor Pressure ◽  
Carrier Concentration ◽  
Reverse Bias ◽  
Deep Level ◽  
Three Dimensional ◽  
Deep Trap ◽  
Concentration Profiles ◽  
Ionization Energies ◽  
Transient Spectroscopy ◽  
Effective Carrier

We have investigated deep trap concentrations in hydride vapor pressure epitaxy (HVPE) - grown GaN by measuring three-dimensional carrier concentration profiles and ionization energies. Schottky contacts were fabricated on 28-68μm thick films using Ni/Au contacts. Extensive capacitance-voltage measurements were made in the temperature range 100-350K at reverse bias voltages in the range 0 to –5V. Effective carrier concentrations and ionization energies were determined from three-dimensional plots of concentration-temperature-depth. Carrier concentration versus temperature plots show slowly changing three-step behavior. During the first step, all the plots rise linearly up to about 200K reaching respective plateaus before reversing courses downwards again linearly. Ionization energy plots, on the other hand, are almost linear all the way up to 350 K showing some tendency of upward bending. Trap concentrations were determined from carrier concentrations and previously measured deep level transient spectroscopy (DLTS) plots as function of reverse bias voltages. In almost every case, trap concentrations also rise linearly with increasing depth in the samples.

Auger Suppression in and Noise Performance of “Hot” HgCdTe IR Detectors

1999 ◽  
Vol 607 ◽  
Author(s):  
F. Benjaminsen ◽  
A. D.van Rheenen ◽  
X.-Y. Chen
Keyword(s):  
Carrier Concentration ◽  
Reverse Bias ◽  
Forward Bias ◽  
Low Frequency ◽  
Differential Resistance ◽  
Frequency Noise ◽  
Narrow Gap ◽  
Noise Performance ◽  
Ir Detectors ◽  
Thermal Generation

AbstractThe carrier concentration in narrow-gap semiconductors operating at room temperature is usually determined by thermal generation, not by doping. By reverse biasing a specially designed HgCdTe P+ - π - N+ heterostructure, the carrier concentrations in the narrow-gap π layer are held below the intrinsic concentration. Temperature dependent measurements of the reverse-bias current-voltage characteristics reveal that the devices operate as "usual" diodes below approximately 225 K. Above this temperature, the intrinsic carrier concentration increases, and the suppression mechanism appears in the I-V curves as negative differential resistance regions. The low-frequency noise performance of these devices, both in the forward bias and the reverse bias regime, as a function of temperature will be presented.

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