Light Induced Defects in a-Si:H, Temperature Dependence of their Creation and Anneal and their effect on Photocarrier Lifetime

1994 ◽  
Vol 336 ◽  
Author(s):  
Paul Stradins ◽  
Hellmut Fritzsche ◽  
Minh Q. Tran
Keyword(s):  
Glow Discharge ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Plasma Discharge ◽  
Hot Wire ◽  
Defect Creation ◽  
Normal Glow Discharge ◽  
Induced Defects ◽  
Kinetics Of ◽  
Effect Of Light

ABSTRACTWe compared the effect of light soaking on the photoresponse and defect concentration ND of samples prepared by normal glow discharge, by remote plasma discharge, by the heated mesh and by the hot wire deposition methods. After exposure to 4×1027 cm−3 absorbed photons all samples have the nearly the same Np and photoresponse. At low temperatures additional defects with small anneal energies are created. Defects created at low temperatures were found to relax between 100K and 300K before they anneal. These new results cannot be explained by present models of defect creation. The kinetics of defect creation at low temperatures is discussed.

Temperature Dependence of the Photoconductivity and the Near Absence of Light-Induced Defects in a-SixGe1-x:H

1996 ◽  
Vol 420 ◽  
Author(s):  
H. Fritzsche ◽  
P. Stradins ◽  
G. Belomoin
Keyword(s):  
Glow Discharge ◽  
Temperature Dependence ◽  
Conduction Band ◽  
Low Temperatures ◽  
Elevated Temperatures ◽  
Thermal Quenching ◽  
Amorphous Si ◽  
Induced Defects ◽  
Band Tails

AbstractThe photoconductivities ap of glow discharge deposited a-Ge:H and amorphous Si-Ge alloys prepared in different laboratories were measured between 4.2K and 300K and compared with σp(T) of intrinsic and compensated a-Si:H films. The alloys as well as a-Ge:H do not exhibit thermal quenching of σp(T) at elevated temperatures which suggests that the valence and conduction band tails have similar widths. Remarkable is the near absence of light-induced metastable defects in the alloys as well as in a-Ge:H even after prolonged exposures at low temperatures.

Ozonation of bromide-containing drinking waters:a delicate balance between disinfection and bromate formation

2000 ◽  
Vol 41 (7) ◽  
pp. 53-59 ◽  
Author(s):  
U. von Gunten ◽  
U. Pinkernell
Keyword(s):  
Temperature Dependence ◽  
Low Temperatures ◽  
The Other ◽  
Ozone Exposure ◽  
Oh Radicals ◽  
Strong Temperature Dependence ◽  
Control Options ◽  
The One ◽  
Kinetics Of ◽  
Ozonation Process

The occurrence of Cryptosporidium in raw waters and bromate formation during ozonation of bromide-containing waters leads to a difficult optimisation of ozonation processes. On the one hand inactivation of Cryptosporidium requires high ozone exposures, on the other hand under these conditions bromate formation is favored. In order to overcome this problem we need information about (i) the oxidant concentrations (ozone and OH radicals) during an ozonation process, (ii) kinetics of the inactivation of Cryptosporidium, (iii) kinetics and mechanism of bromate formation, and (iv) the reactor hydraulics. The strong temperature dependence of the inactivation of Cryptosporidium which results in a higher ozone exposure (time-integrated action of ozone) at low temperatures makes it more difficult to fulfil disinfection and bromate standards at low temperatures. Underthese conditions control options for bromate formation can be applied. Depressionof pH and addition of ammonia have been selected to be the best options. For a given ozone exposure both measures lead to a reduction of bromate formation in the order of 50%.

Kinetics of a-Si:H Crystallization Induced by Gold at Low Temperatures

1992 ◽  
Vol 258 ◽  
Author(s):  
A.A. Pasa ◽  
M.B. Schubert ◽  
C.-D. Abel ◽  
W. Beyer ◽  
W. Losch ◽  
...  
Keyword(s):  
Activation Energy ◽  
Glow Discharge ◽  
Film Thickness ◽  
Raman Spectra ◽  
Low Temperatures ◽  
Crystallization Rate ◽  
Au Film ◽  
Annealing Conditions ◽  
Kinetics Of ◽  
Induced Crystallization

ABSTRACTThe Au-induced crystallization of a-Si:H has been studied by evaporating Au films of different thicknesses onto intrinsic glow discharge deposited a-Si:H layers. The presence of a sharp peak in the Raman spectra (FWHM≈9 cm-1, ω516 cm-1) of samples with a Au thickness larger than 2 nm, which have been annealed in vacuum at 400K≤T≤600K, indicate that the crystallites have approximately the same size (6nm) regardless of the annealing conditions. An investigation of crystallization versus Au-film thickness revealed, that the total crystallized volume is increasing with Au thickness, and furthermore a saturation of the crystallized volume takes place, most probably due to an exhaustion of the Au reservoir. The increase of crystallization rate with temperature follows an Arrhenius-like dependence with an activation energy of 1.1 eV. Changes in hydrogen content as a consequence of the crystallization have been monitored by H-effusion measurements: Au-coated a-Si:H samples show a strong H2 evolution at temperatures substantially lower than uncoated ones.

Electron Drift Mobility in a-Si:H Prepared by Hot-Wire Deposition

1995 ◽  
Vol 377 ◽  
Author(s):  
Qing Gu ◽  
E. A. Schiff ◽  
R. S. Crandall ◽  
E. Iwaniczko ◽  
B. Nelson
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Time Of Flight ◽  
Drift Mobility ◽  
Electron Drift ◽  
Hot Wire ◽  
Initial Work ◽  
Normal Glow Discharge ◽  
Silicon Based ◽  
Electron Drift Mobility

ABSTRACTWe have measured the electron drift mobility in a-Si:H prepared by hot wire (HW) deposition using photocarrier time-of-flight. Initial work has shown that light-soaked HW material can have much better ambipolar diffusion lengths than the plasma-deposited material following extended light soaking. In a sample with about 2% H-concentration in the intrinsic layer, we find that the electron drift mobility is quite different from that of a-Si:H alloys prepared by normal glow-discharge CVD, even allowing for the reduced bandgap of the hot Wire material. This result challenges the principle that the bandgap of optimized amorphous silicon based material is sufficient to predict the electron drift mobility.

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

93Nb Nuclear Spin-Spin Relaxation in the Low-Dimensional Antiferromagnet Fe0.25NbS2

2007 ◽  
Vol 62 (10-11) ◽  
pp. 627-632
Author(s):  
Noriaki Okubo
Keyword(s):  
Temperature Dependence ◽  
Spin Relaxation ◽  
Nuclear Spin ◽  
Low Temperatures ◽  
Fast Decay ◽  
Low Dimensional

93Nb nuclear spin-spin relaxation has been examined in the low-dimensional antiferromagnet Fe0.25NbS2 between 4.2 K and 300 K. The relaxation is characterized by two T2’s. The temperature dependence is discussed together with the origin of the disappearance of the fast decay at low temperatures.

Sign in / Sign up

Export Citation Format

Share Document