scholarly journals Electronic structure of dangling bonds in amorphous silicon studied via a density-matrix functional method

2002 ◽  
Vol 66 (19) ◽  
Author(s):  
R. G. Hennig ◽  
P. A. Fedders ◽  
A. E. Carlsson
Keyword(s):  
Electronic Structure ◽  
Density Matrix ◽  
Amorphous Silicon ◽  
Functional Method ◽  
Dangling Bonds

Electronic Structure of Defects in Amorphous Silicon Nitride

1992 ◽  
Vol 284 ◽  
Author(s):  
John Robertson
Keyword(s):  
Electronic Structure ◽  
Silicon Nitride ◽  
Percolation Threshold ◽  
Amorphous Silicon ◽  
Electronic Properties ◽  
Valence Band ◽  
Band Edge ◽  
Valence Band Edge ◽  
Dangling Bonds ◽  
Amorphous Silicon Nitride

ABSTRACTThe paper reviews the electronic properties of defects in amorphous silicon nitride (a-Si3N4) and the hydrogenated alloys a-SiNx:H. The main defects in a-Si3N4 are the Si and N dangling bonds (DBs). The Si DB forms a sp3 state near midgap, while the N DB forms a highly localized pπ level just above the valence band edge. The behaviour of the alloys changes near x ≈ 1.1, the percolation threshold of Si-Si bonds. In the Si-rich alloys, both band edges are Si-like, only Si DBs are seen and their density is controlled by equilibration with weak Si-Si bonds. The x>1.1 alloys behave like silicon nitride; the valence band changes towards N pπ-like, both Si and N DBs can arise, the Si DB can have a high density and prefers to be in its charged diamagnetic configurations.

Metastable Defects in the Amorphous Silicon-Germanium Alloys

2003 ◽  
Vol 762 ◽  
Author(s):  
J. David Cohen
Keyword(s):  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Dangling Bonds ◽  
Annealing Behavior ◽  
Fundamental Properties ◽  
Silicon Materials ◽  
Salient Features ◽  
The Individual ◽  
Amorphous Silicon Germanium ◽  
Silicon Germanium Alloys

AbstractThis paper first briefly reviews a few of the early studies that established some of the salient features of light-induced degradation in a-Si,Ge:H. In particular, I discuss the fact that both Si and Ge metastable dangling bonds are involved. I then review some of the recent studies carried out by members of my laboratory concerning the details of degradation in the low Ge fraction alloys utilizing the modulated photocurrent method to monitor the individual changes in the Si and Ge deep defects. By relating the metastable creation and annealing behavior of these two types of defects, new insights into the fundamental properties of metastable defects have been obtained for amorphous silicon materials in general. I will conclude with a brief discussion of the microscopic mechanisms that may be responsible.

Model of hydrogenated amorphous silicon and its electronic structure

1993 ◽  
Vol 47 (7) ◽  
pp. 3991-3994 ◽  
Author(s):  
J. M. Holender ◽  
G. J. Morgan ◽  
R. Jones
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogenated Amorphous

scholarly journals Modeling of Beta Conductivity in Tritiated Amorphous Silicon

2000 ◽  
Vol 609 ◽  
Author(s):  
Stefan Costea ◽  
Franco Gaspari ◽  
Tome Kosteski ◽  
Stefan Zukotynski ◽  
Nazir P. Kherani ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Amorphous Silicon ◽  
Silicon Film ◽  
Radioactive Decay ◽  
Dangling Bonds ◽  
Electron Hole ◽  
Beta Particles ◽  
Amorphous Silicon Film ◽  
Recombination Centers

ABSTRACTThe change with time in the electrical conductivity of a hydrogenated-tritiated amorphous silicon film (a-Si:H:T) has been studied. The conductivity decreased with time after deposition. A model is developed to account for the decrease. The radioactive decay of tritium into helium produces energetic beta particles. Each β particle creates over 1500 electron-hole pairs in the film thereby increasing the conductivity of the film. The 3He atoms diffuse away leaving dangling bonds behind. We find that neutral dangling bonds (D0) are responsible for the decrease in conductivity by acting as recombination centers in the material.

Effect of under- and overcoordination on the electronic structure of amorphous silicon

1989 ◽  
Vol 39 (5) ◽  
pp. 3445-3448 ◽  
Author(s):  
L. Martín-Moreno ◽  
J. A. Vergés
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon

Luminescent Amorphous Silicon Layers

1997 ◽  
Vol 486 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon ◽  
Radiative Recombination ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Blue Shift ◽  
Localized States ◽  
Structure Model ◽  
Radiative Recombination Rate ◽  
Tight Binding Approximation

AbstractThe electronic structure of amorphous silicon layers has been calculated within the empirical tight binding approximation using the Wooten-Winer-Weaire atomic structure model. We predict an important blue shift due to the confinement for layer thickness below 3 nm and we compare with crystalline silicon layers. The radiative recombination rate is enhanced by the disorder and the confinement but remains quite small. The comparison of our results with experimental results shows that the density of defects and localized states in the studied samples must be quite small.

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