The Influence of Tunneling Transitions on Recombination and Photoconductivity of a-Si:H

1990 ◽  
Vol 192 ◽  
Author(s):  
B. Cleve ◽  
P. Thomas
Keyword(s):  
Activation Energy ◽  
Fermi Level ◽  
Low Temperatures ◽  
Thermal Quenching ◽  
Rate Equations ◽  
Dangling Bond ◽  
Conventional Model ◽  
Model Based ◽  
Recombination Centers

ABSTRACTSpin dependent photoconductivity measurements provide evidence for the existence of tunneling transitions from localized tail states into the dangling bond recombination centers. These processes can be included approximately into the conventional model based on rate equations. Satisfactory values for the activation energy of the photoconductivity at low temperatures are obtained. Our model produces thermal quenching and an enhancement of the photoconductivity with rising dark Fermi level.

Two Carrier Sensitization as a Spectroscopic Tool for a-Si:H

1999 ◽  
Vol 557 ◽  
Author(s):  
L.F. Fonseca ◽  
S.Z. Weisz ◽  
R. Rapaport ◽  
I. Balberg
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Thermal Quenching ◽  
Minority Carrier Lifetime ◽  
Dangling Bond ◽  
Recent Letter ◽  
Recombination Centers ◽  
Spectroscopic Tool ◽  
Hydrogenated Amorphous ◽  
Effect Of Light

AbstractIn a recent letter we have reported the first observation of the phenomenon of minority carrier-lifetime sensitization in hydrogenated amorphous silicon (a-Si:H). We find now that combining the study of this phenomenon with the study of the well-known phenomenon of majority carrier lifetime sensitization, in this material, can provide direct information on its density of states (DOS) distribution. This finding is important in view of the limitations associated with other methods designed for the same purpose. We have carried out then an experimental study of the effect of light soaking on the phototransport in a-Si:H. We found that the increase of the dangling bond concentration with light soaking affects the sensitization and thermal quenching of the majority carriers lifetime. Using computer simulations, we further show that the details of the observations associated with the sensitization effect yield semiquantitative information on the concentration and character of the recombination centers in a-Si:H.

New experiments on the relationship between light-induced defects and photoconductivity degradation

2001 ◽  
Vol 664 ◽  
Author(s):  
Stephan Heck ◽  
Howard M. Branz
Keyword(s):  
Activation Energy ◽  
Defect Density ◽  
Activation Energies ◽  
Dangling Bond ◽  
Fast Recovery ◽  
Slow Recovery ◽  
Degradation Model ◽  
Induced Defects ◽  
The Relationship ◽  
Hydrogenated Amorphous

ABSTRACTWe report experimental results that help settle apparent inconsistencies in earlier work on photoconductivity and light-induced defects in hydrogenated amorphous silicon (a-Si:H) and point toward a new understanding of this subject. After observing that light-induced photoconductivity degradation anneals out at much lower T than the light-induced increase in deep defect density, Han and Fritzsche[1] suggested that two kinds of defects are created during illumination of a-Si:H. In this view, one kind of defect degrades the photoconductivity and the other increases defect sub-bandgap optical absorption. However, the light-induced degradation model of Stutzmann et al.[2] assumes that photoconductivity is inversely proportional to the dangling-bond defect density. We observe two kinds of defects that are distinguished by their annealing activation energies, but because their densities remain in strict linear proportion during their creation, the two kinds of defects cannot be completely independent.In our measurements of photoconductivity and defect absorption (constant photocurrent method) during 25°C light soaking and during a series of isochronal anneals between 25 < T < 190°C, we find that the absorption measured with E ≤1.1 eV, first increases during annealing, then exhibits the usual absorption decrease found for deeper defects. The maximum in this absorption at E ≤1.1eV occurs simultaneously with a transition from fast to slow recovery of photoconductivity. The absorption for E ≤1.1eV shows two distinct annealing activation energies: the signal rises with about 0.87 eV and falls with about 1.15 eV. The 0.87 eV activation energy roughly equals the activation energy for the dominant, fast, recovery of photoconductivity. The 1.15 eV activation energy roughly equals the single activation energy for annealing of the light-induced dangling bond absorption.

P+ implanted 6H-SiC n+-i-p diodes: evidence for a post-implantation-annealing dependent defect activation

2014 ◽  
Vol 1693 ◽  
Author(s):  
R. Nipoti ◽  
M. Puzzanghera ◽  
F. Moscatelli
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Ideality Factor ◽  
Low Voltage ◽  
Reverse Current ◽  
Forward Current ◽  
Current Region ◽  
Recombination Centers ◽  
Energy Dependent ◽  
Post Implantation

ABSTRACTTwo n+-i-p 6H-SiC diode families with P+ ion implanted emitter have been processed with all identical steps except the post implantation annealing: 1300°C/20min without C-cap has been compared with 1950°C/10min with C-cap. The analysis of the temperature dependence of the reverse current at low voltage (-100V) in the temperature range 27-290°C shows the dominance of a periphery current which is due to generation centers with number and activation energy dependent on the post implantation annealing process. The analysis of the temperature dependence of the forward current shows two ideality factor n region, one with n = 1.9/2 at low voltage and the other one with 1 < n < 2 without passing through 1 for increasing voltages. For both the diode families the current with n = 1.9/2 is a periphery current due to recombination centers with a thermal activation energy near the 6H-SiC mid gap. In the forward current region of 1 < n < 2, the two diode families show different ideality factor values which could be attributed to a different post implantation annealing defect activation.

Study of Donor Centres in n-InSb due to the Temperature Annealing

2005 ◽  
Vol 480-481 ◽  
pp. 197-200
Author(s):  
Y. Sayad ◽  
A. Nouiri
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Theoretical Study ◽  
Donor Concentration ◽  
Model Based ◽  
Proposed Model ◽  
Kinetics Of ◽  
Best Fit

An increasing of donor centres has been detected in n-InSb when it was submitted to anneal/quench with various annealing temperature (450 °C - 850 °C) and various annealing time (5 - 100 hours). A theoretical study of the kinetics of the conduction conversion of n-InSb at temperature annealing above 250 °C has been made. The present analysis indicates that the donor concentration increases with increasing of annealing time. In order to study this variation and to give a model for donor centres generated, a proposed model based on the simple kinetic is used to fit the variation of donor concentration as a function of annealing time. However, from the best fit of experimental data using the proposed model, the activation energy is determined.

Oxygen diffusion in amorphous and partially crystalline gallium oxide

2019 ◽  
Vol 21 (8) ◽  
pp. 4268-4275 ◽  
Author(s):  
Alexandra von der Heiden ◽  
Manuel Bornhöfft ◽  
Joachim Mayer ◽  
Manfred Martin
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficients ◽  
Low Temperatures ◽  
Oxygen Diffusion ◽  
Gallium Oxide ◽  
Tracer Diffusion ◽  
Tof Sims ◽  
Tracer Diffusion Coefficients ◽  
Oxygen Tracer

We established a TTT diagram of crystallisation of gallium oxide. Determination of oxygen tracer diffusion coefficients by IEDP/ToF-SIMS allowed us to access the activation energy for amorphous GaO1.5 at low temperatures.

THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOUR. II.

1947 ◽  
Vol 25b (2) ◽  
pp. 135-150 ◽  
Author(s):  
Paul A. Giguère
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Low Temperatures ◽  
Hydrocyanic Acid ◽  
Quartz Surface ◽  
First Order ◽  
Acid Washing ◽  
Reaction Vessels ◽  
Low Pressures

The decomposition of hydrogen peroxide vapour has been investigated at low pressures (5 to 6 mm.) in the temperature range 50° to 420 °C., for the purpose of determining the effect of the nature and treatment of the active surfaces. The reaction was followed in an all-glass apparatus and, except in one case, with one-litre round flasks as reaction vessels. Soft glass, Pyrex, quartz, and metallized surfaces variously treated were used. In most cases the decomposition was found to be mainly of the first order but the rates varied markedly from one vessel to another, even with vessels made of the same type of glass. On a quartz surface the decomposition was preceded by an induction period at low temperatures. Fusing the glass vessels slowed the reaction considerably and increased its apparent activation energy; this effect was destroyed by acid washing. Attempts to poison the surface with hydrocyanic acid gave no noticeable result. The marked importance of surface effects at all temperatures is considered as an indication that the reaction was predominantly heterogeneous under the prevailing conditions. Values ranging from 8 to 20 kcal. were found for the apparent energy of activation. It is concluded that the decomposition of hydrogen peroxide vapour is not very specific as far as the nature of the catalyst is concerned.

Kinetic Studies on the Synthesis of Hydroxyapatite Nanowires by Solvothermal Methods

2007 ◽  
Vol 60 (2) ◽  
pp. 99 ◽  
Author(s):  
Shiying Zhang ◽  
Chen Lai ◽  
Kun Wei ◽  
Yingjun Wang
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Kinetic Studies ◽  
Axial Ratio ◽  
Reaction Rate Constant ◽  
Rate Equations ◽  
Solvothermal Reaction ◽  
Growth Order ◽  
Constant Diffusion ◽  
Solvothermal Methods

Hydroxyapatite nanowires with a high axial ratio have been synthesized in reverse micelle solutions that consist of cetyltrimethylammonium bromide (CTAB), n-pentanol, cyclohexane, and the reactant solution by solvothermal methods. This paper focusses on the kinetic studies of the solvothermal reaction and the linear growth of hydroxyapatite nanowires. When the reaction was carried out at low temperatures (65°C), the experimental results showed that the reaction rate was of zero order since the whole reaction was diffusion controlled with constant diffusion coefficients. In the middle to high temperature range (130–200°C), the kinetics were characterized by second order reaction kinetics. Since the controlling factor was activation energy and the apparent activation energy was large, the reaction rate was more sensitive to the temperature. Therefore, the exponent of the reaction rate constant increased by two when the temperature was increased from 130 to 200°C. By calculating the yields of products and the specific surface areas at different times, the linear and overall growth rate equations of the hydroxyapatite nanowires could be obtained. The experimental effective growth order of the crystals was 11. The larger growth order indicated that the crystal could grow more effectively in one direction because of the induction of the surfactant in the experiment system.

Hydrogen Embrittlement Of Austenitic Stainless Steel

CORROSION ◽  
1965 ◽  
Vol 21 (2) ◽  
pp. 53-56 ◽  
Author(s):  
M. B. WHITEMAN ◽  
A. R. TROIANO
Keyword(s):  
Activation Energy ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperatures ◽  
High Strain ◽  
Complete Recovery ◽  
Strain Rates ◽  
Body Centered Cubic ◽  
Thin Sections ◽  
310 Stainless Steel

Abstract Type 310 stainless steel in thin sections was embrittled by hydrogen. The temperature and strain rate dependence of this embrittlement was almost analogous to that well-established for hydrogenated body-centered cubic (b.c.c.) metals, differing only in that at low temperatures and relatively high strain rates complete recovery in ductility was not achieved. The activation energy for recovery in ductility, determined by aging at several temperatures, was 10,900 cal/mole.

Retailer’s Ordering and Discounting Policies Under Advance Sales Discount and Trade Credit Based on Sharia

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Chairul Saleh ◽  
Achmad Chairdino Leuveano ◽  
Reny Lagaida ◽  
Md. Razali Muhammad
Keyword(s):  
Mathematical Model ◽  
Cycle Time ◽  
Trade Credit ◽  
Price Discount ◽  
Inventory Cost ◽  
Conventional Model ◽  
Credit Period ◽  
Model Based ◽  
Advance Sales ◽  
Replenishment Cycle

The use of conventional model to minimize the inventory cost creates a disturbance between the sellers and buyers. It creates a usury since the payment conducts to interest paid and interest earned. In this paper, sharia principle is implemented, that is Bai Al Istishna which allows credit period and margin agreement as the payment. The model is engaged to replenishment cycle time and price discount policy to attract the customer’s demand which based on sharia principle. This paper provides a useful mathematical model based on sharia principles in order to usury/interest can be eliminated in the trading process.

scholarly journals Interplay between spin crossover and proton migration along short strong hydrogen bonds

2021 ◽  
Author(s):  
Verónica Jornet-Mollá ◽  
Carlos Giménez-Saiz ◽  
Laura Cañadillas-Delgado ◽  
Dmitry S. Yufit ◽  
Judith A. K. Howard ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Low Temperatures ◽  
Energy Barrier ◽  
Spin Crossover ◽  
Strong Hydrogen Bond ◽  
Activation Energy Barrier ◽  
Proton Migration

A proton migration across a short strong hydrogen bond can be triggered by spin crossover of a remote Fe2+ cation, with the onset of a photoinduced activation energy barrier for proton motion at low temperatures.

Sign in / Sign up

Export Citation Format

Share Document