Correlations between higher-order rings and microvoids in hydrogenated amorphous silicon

Experimental Information ◽

Higher Order ◽

ABSTRACTIn this paper we report the structure of voids in several thousand atom models of hydrogenated amorphous silicon. The models are produced by jointly employing experimental information from Smets and coworkers [1] and first principles simulations [2]. We demonstrate the existence of a useful correlation between the presence of large irreducible rings and the voids in hydrogenated amorphous silicon networks. Molecular hydrogen is observed in the models, and discussed.

Coordination defects in amorphous silicon and hydrogenated amorphous silicon: a characterization from first-principles calculations

Philosophical Magazine B ◽

10.1080/014186300255168 ◽

2000 ◽

Vol 80 (4) ◽

pp. 515-521 ◽

Cited By ~ 2

Author(s):

M. Peressi, M. Fornari, S. De Gironcol

Keyword(s):

Amorphous Silicon ◽

First Principles ◽

First Principles Calculations ◽

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

MRS Proceedings ◽

10.1557/proc-219-593 ◽

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 ◽

Sulphur Content ◽

Defect States ◽

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.

First principles calculation of the electronic structure of hydrogenated amorphous silicon

Journal of Non-Crystalline Solids ◽

10.1016/0022-3093(85)90611-8 ◽

1985 ◽

Vol 77-78 ◽

pp. 63-66

Author(s):

G. Díaz ◽

E. Martínez ◽

Felex Ynduráin

Keyword(s):

Electronic Structure ◽

Amorphous Silicon ◽

First Principles ◽

First Principles Calculation ◽

Ortho-molecular hydrogen in hydrogenated amorphous silicon

Applied Physics Letters ◽

10.1063/1.125818 ◽

2000 ◽

Vol 76 (5) ◽

pp. 565-567 ◽

Cited By ~ 1

Author(s):

Tining Su ◽

P. C. Taylor ◽

Shenlin Chen ◽

R. S. Crandall ◽

A. H. Mahan

Keyword(s):

Amorphous Silicon ◽

Molecular Hydrogen ◽

First-principles Modeling of Structure, Vibrations, Electronic Properties and Bond Dynamics in Hydrogenated Amorphous Silicon: Theory versus Experiment

MRS Proceedings ◽

10.1557/proc-1153-a18-03 ◽

2009 ◽

Vol 1153 ◽

Author(s):

Anatoli Shkrebtii ◽

Ihor Kupchak ◽

Franco Gaspari

Keyword(s):

Amorphous Silicon ◽

Electronic Properties ◽

First Principles ◽

Hydrogen Diffusion ◽

Amorphous Structure ◽

Material Structure ◽

Electron Charge Density ◽

Wide Range ◽

AbstractWe carried out extensive first-principles modeling of microscopic structural, vibrational, electronic properties and chemical bonding in hydrogenated amorphous silicon (a-Si:H) in a wide range of hydrogen concentration and preparation conditions. The theory has been compared with experimental results to comprehensively characterize this semiconductor material. The computer modeling includes ab-initio Molecular Dynamics (MD), atomic structure optimization, advanced signal processing and computer visualization of dynamics. We extracted parameters of hydrogen and silicon bonding, electron charge density and calculated electron density of states (EDOS) and hydrogen diffusion. A good agreement of the theory with various experiments allowed us to correlate microscopic processes at the atomic level with macroscopic properties. Here we focus on correlation of the amorphous structure of the material, atom dynamics and electronic properties. These results are of increasing interest due to extensive application of a-Si:H in modern research and technology and to the significance of detailed understanding of the material structure, bonding, disordering mechanisms and stability.

Photovoltaic devices using hydrogenated amorphous silicon produced by the chemical vapor deposition of higher order silanes. Final report, 1 August 1982-31 August 1983

10.2172/5628846 ◽

1985 ◽

Author(s):

A. Delahoy

Keyword(s):

Chemical Vapor Deposition ◽

Amorphous Silicon ◽

Vapor Deposition ◽

Chemical Vapor ◽

Higher Order ◽

Final Report ◽

Photovoltaic Devices ◽

A first principles analysis of the effect of hydrogen concentration in hydrogenated amorphous silicon on the formation of strained Si-Si bonds and the optical and mobility gaps

Journal of Applied Physics ◽

10.1063/1.4880395 ◽

2014 ◽

Vol 115 (20) ◽

pp. 203711 ◽

Cited By ~ 8

Author(s):

Merid Legesse ◽

Michael Nolan ◽

Giorgos Fagas

Keyword(s):

Amorphous Silicon ◽

Hydrogen Concentration ◽

First Principles ◽

Strained Si ◽

Computational experiment in non-crystalline materials from first-principles: A case study of vibrations in hydrogenated amorphous silicon

10.1063/1.4771851 ◽

2012 ◽

Author(s):

Franco Gaspari ◽

Anatoli I. Shkrebtii ◽

Ihor M. Kupchak ◽

Tim Teatro ◽

Laura Henderson

Keyword(s):

Amorphous Silicon ◽

First Principles ◽

Computational Experiment ◽

Crystalline Materials ◽

Molecular Hydrogen in Hot-Wire Hydrogenated Amorphous Silicon

MRS Proceedings ◽

10.1557/proc-507-595 ◽

1998 ◽

Vol 507 ◽

Cited By ~ 6

Author(s):

Xiao. Liu ◽

E. Iwaniczko ◽

R.O. Pohl ◽

R.S. Crandall

Keyword(s):

Internal Friction ◽

Amorphous Silicon ◽

Molecular Hydrogen ◽

Solid Phase ◽

Chemical Vapor ◽

Amorphous Solid ◽

Hot Wire ◽

Hydrogenated Amorphous ◽

Triple Point Temperature

ABSTRACTWe have studied the elastic properties of hydrogenated amorphous silicon (a-Si:H) prepared by hot wire chemical-vapor deposition (HWCVD). With 1 at.% H, this material has been found to be the only amorphous solid which has a low-temperature internal friction more than two orders of magnitude smaller than all other amorphous solids studied to date, as reported recently. As the hydrogen concentration increases above 1 at.%, a broad relaxation peak in internal friction around 5 K is observed. Even more striking is an extremely narrow peak in internal friction accompanied by a discontinuous change in the sound velocity at 13.8 K, which coincides with the triple point temperature of molecular hydrogen. Evidences are provided to show that this anomaly is caused by bulk molecular hydrogen which undergoes a liquid-solid phase transition. This is the first observation for the existence of bulk H2 in HWCVD a-Si:H.

Nuclear Magnetic Resonance Studies of Hydrogen in Amorphous Silicon

MRS Proceedings ◽

10.1557/proc-420-475 ◽

1996 ◽

Vol 420 ◽

Cited By ~ 9

Author(s):

R. E. Norberg ◽

P. A. Fedders ◽

D. J. Leopold

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Amorphous Silicon ◽

Molecular Hydrogen ◽

High Quality ◽

Magnetic Resonance Studies ◽

Structural Configurations ◽

Species Specific ◽

AbstractProton and deuteron NMR in hydrogenated amorphous silicon yield quantitative measures of species-specific structural configurations and their dynamics. Populations of silicon-bonded and molecular hydrogens correlate with photovoltaic quality, doping, illumination/dark anneal sequences, and with infrared and other characterizations. High quality films contain substantial populations of nanovoid-trapped molecular hydrogen.