Bonded Hydrogen Atom Participation in Metastable Defect Formation in Hydrogenated Amorphous Silicon

1998 ◽  
Vol 507 ◽  
Author(s):  
G. Lucovsky ◽  
H. Yang
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Amorphous Silicon ◽  
Defect Formation ◽  
Hydrogenated Amorphous Silicon ◽  
Reaction Pathways ◽  
Reaction Barriers ◽  
Hydrogenated Amorphous ◽  
Metastable Defect

ABSTRACTThis paper proposes intrinsic reaction pathways for generation of metastable defects in hydrogenated undoped or intrinsic amorphous silicon (i-a-Si:H). Since these pathways involve only silicon (Si) and hydrogen (H) atoms, this approach is valid for device grade materials in which concentrations of oxygen (0) atoms, and nitrogen-hydrogen (N-H) groups are present at concentrations below about 1019 cm−3. Ab initio calculations demonstrate that the proposed generation pathway reactions are exothermic with relatively small reaction barriers (< 0.4 eV).

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.

Ab Initio Calculation of Infrared and Raman Spectra for Hydrogenated Amorphous Silicon

1994 ◽  
Vol 184 (2) ◽  
pp. 553-557
Author(s):  
Xian-Wu Zou ◽  
Wen-Bing Zhang ◽  
Hong-Zhang Zhuang ◽  
Zhun-Zhi Jin
Keyword(s):  
Ab Initio ◽  
Amorphous Silicon ◽  
Raman Spectra ◽  
Ab Initio Calculation ◽  
Hydrogenated Amorphous Silicon ◽  
Infrared And Raman Spectra ◽  
Hydrogenated Amorphous
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