scholarly journals Light-induced defect states in hydrogenated amorphous silicon centered around 1.0 and 1.2 eV from the conduction band edge

2003 ◽  
Vol 83 (18) ◽  
pp. 3725-3727 ◽  
Author(s):  
J. M. Pearce ◽  
J. Deng ◽  
R. W. Collins ◽  
C. R. Wronski
Keyword(s):  
Amorphous Silicon ◽  
Conduction Band ◽  
Hydrogenated Amorphous Silicon ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Defect States ◽  
Hydrogenated Amorphous

scholarly journals Analytical Study of near Mobility Edge Density of States of Hydrogenated Amorphous Silicon

2014 ◽  
Vol 11 (3) ◽  
pp. 1243-1249
Author(s):  
Baghdad Science Journal
Keyword(s):  
Amorphous Silicon ◽  
Valence Band ◽  
Conduction Band ◽  
Density Of States ◽  
Power Law ◽  
Power Index ◽  
Hydrogenated Amorphous Silicon ◽  
Band Edge ◽  
Simple Power ◽  
Hydrogenated Amorphous

Experimental results for the density of states of hydrogenated amorphous silicon due to Jackson et al near the valence and conduction band edges were analyzed using Levenberg-Marquardt nonlinear fitting method. It is found that the density of states of the valence band and the conduction band can be fitted to a simple power law, with a power index 0.60 near the valence band edge, and 0.55 near the conduction band edge. These results indicate a modest but noticeable deviation from the square root law (power index=0.5) which is found in crystalline semiconductors. Analysis of Jackson et al density of states integral J(E) data over about (1.4 eV) of photon energy range, showed a significant fit to a simple power law with a power index of 2.11 close to that predicted from the density of states fitting results 2.15

The Effects of Coordination and Local Disorder on Impurity States in Hydrogenated Amorphous Silicon

1987 ◽  
Vol 95 ◽  
Author(s):  
C. S. Nichols ◽  
C. Y. Fong
Keyword(s):  
Amorphous Silicon ◽  
Disordered Systems ◽  
Hydrogenated Amorphous Silicon ◽  
Lone Pair ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Geometrical Distortion ◽  
Periodic Model ◽  
Gap States ◽  
Hydrogenated Amorphous

AbstractThe self-consistent pseudopotential method has been used to calculate the electronic structure of a periodic model of hydrogenated amorphous silicon containing, independently, P and B impurities. We have investigated both impurities in threefold- and fourfold-coordinated sites. Both types of sites studied also include the realistic distortion inherent in disordered systems. In fourfold coordination, both P and B introduce gap states, the energy and spatial extent of which depend upon the local geometrical distortion. In threefold coordination, the lone pair state of P is found below the valence band edge, while the B non-bonding state is found above the conduction band edge. The effects of local geometrical distortion on both of these states is also discussed. Comparisons with other calculations and experimental results are made.

Theoretical Studies of Structure and Doping of Hydrogenated Amorphous Silicon

2011 ◽  
Vol 1321 ◽  
Author(s):  
Bin Cai ◽  
D. A. Drabold
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Theoretical Studies ◽  
Defect States ◽  
High Impurity ◽  
Bond Center ◽  
B Doping ◽  
Hydrogenated Amorphous ◽  
Center Site

ABSTRACTIn a-Si:H, large concentrations of B or P (of order 1%) are required to dope the material, suggesting that doping mechanisms are very different than for the crystal for which much smaller concentrations are required. In this paper, we report simulations on B and P introduced into realistic models of a-Si:H and a-Si, with concentrations ranging from 1.6% to 12.5% of B or P in the amorphous host. The results indicate that tetrahedral B and P are effective doping configurations in a-Si, but high impurity concentrations introduce many defect states. For a-Si:H, we report that both B(3,1) and P(3,1) (B or P atom bonded with three Si atoms and one H atom) are effective doping configurations. We investigate H passivation in both cases. For both B and P, there exists a “hydrogen poison range” of order 6 Å for which H in a bond-center site can suppress doping. For B doping, nearby H prefers to stay at the bond-center of Si-Si, leaves B four-fold and neutralizes the doping configuration; for P doping, nearby H spoils the doping by inducing a reconstruction rendering initially tetrahedral P three-fold.

Defect States in Hydrogenated Amorphous Silicon-Sulphur Alloys by ESR and PAS

1991 ◽  
Vol 219 ◽  
Author(s):  
Gaorong Han ◽  
Jianmin Qiao ◽  
Piyi Du ◽  
Zhonghua Jiang ◽  
Zishang Ding
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Spin Density ◽  
Molecular Hydrogen ◽  
Annealing Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Sulphur Content ◽  
Defect States ◽  
Hydrogenated Amorphous

ABSTRACTWe have presented ESR and PAS measurements for a series of a-SiS:H and a-Si: H films deposited by glow discharge at different parameters. The spin density in a-SiS:H alloys measured by ESR is essentially independent of the sulphur content, while the density of defects measured by PAS increases significantly with the increasing of sulphur content. The ESR signals in a-SiS:H alloys strongly depend on both annealing and illumination. The spin density increases up to 540°C and then decreases with raising annealing temperature for a-SiS:H and a-Si:H alloys. The results suggest that some new defects such as molecular hydrogen and microvoids are appeared when addition of sulphur to a-Si:H films.

Charged defect states in intrinsic hydrogenated amorphous silicon films

1994 ◽  
Vol 76 (4) ◽  
pp. 2260-2263 ◽  
Author(s):  
Mehmet Güneş ◽  
Christopher R. Wronski ◽  
T. J. McMahon
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Films ◽  
Charged Defect ◽  
Defect States ◽  
Hydrogenated Amorphous
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