New Model for “Stretched Exponential” Relaxation

1996 ◽  
Vol 420 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
Experimental Data ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Statistical Distributions ◽  
New Model ◽  
Stretched Exponential ◽  
Careful Treatment ◽  
Exponential Relaxation ◽  
Hydrogenated Amorphous

AbstractA new model to explain stretched exponential relaxation in hydrogenated amorphous silicon is presented. The model does not invoke statistical distributions; rather, it is based on a careful treatment of diffusion, including retrapping. Excellent fits to a variety of experimental data are obtained.

Steady-State Photoconductivity in Undoped Amorphous Silicon

1989 ◽  
Vol 149 ◽  
Author(s):  
Jeffrey Zhaohuai Liu ◽  
S. Wagner
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Steady State ◽  
Amorphous Silicon ◽  
Thermal Activation ◽  
Hydrogenated Amorphous Silicon ◽  
Thermal Activation Energy ◽  
Strong Temperature Dependence ◽  
Quasi Fermi Level ◽  
Hydrogenated Amorphous

ABSTRACTAn analytical expression for the thermal activation energy of the steady-state photoconductivity is shown to agree with experimental data in a range of temperature and generation rate for undoped hydrogenated amorphous silicon (a-Si:H). This agreement supports our suggestion that the commonly observed small activation energy of the photoconductivity in undoped a-Si:H originates in the strong temperature dependence of the quasi-Fermi level for electrons.

Mechanisms for Metastability in Hydrogenated Amorphous Silicon

2000 ◽  
Vol 609 ◽  
Author(s):  
R. Biswas ◽  
Y.-P. Li ◽  
B.C. Pan
Keyword(s):  
Amorphous Silicon ◽  
Structural Changes ◽  
Defect Formation ◽  
Hydrogenated Amorphous Silicon ◽  
Dangling Bond ◽  
Dangling Bonds ◽  
New Model ◽  
Gap States ◽  
Hydrogenated Amorphous ◽  
Metastable Defect

ABSTRACTWe propose metastabilities in amorphous silicon fall into two classes. One class is the local changes of structure affecting a macroscopic fraction of sites. The other class is the metastable generation of dangling bonds with mid-gap states. The local metastability is explained by a new metastable state formed when H is flipped to the backside of the Si-H bond at monohydride sites. The dipole moment of this H-flip defect is larger and increases the infrared absorption. This H-flip defect accounts for large structural changes observed on light soaking including larger absorption and volume dilation. We propose a new model for the generation of metastable dangling bonds. The new ‘silicon network rebonding model’ involves breaking of weak silicon bonds and formation of isolated dangling bonds, through rebonding of the silicon network. Hydrogen motion is not involved in metastable defect formation. Defect formation proceeds by breaking weak silicon bonds and formation of dangling bond-floating bond pairs. The floating bonds migrate through the network and annihilate, producing isolated dangling bonds. This new model provides a new platform for understanding the atomistic origins of lightinduced degradation.

BONDING IN HYDROGENATED AMORPHOUS SILICON

1981 ◽  
Vol 42 (C4) ◽  
pp. C4-773-C4-777 ◽  
Author(s):  
H. R. Shanks ◽  
F. R. Jeffrey ◽  
M. E. Lowry
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogenated Amorphous
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