Ortho-molecular hydrogen in hydrogenated amorphous silicon

2000 ◽  
Vol 76 (5) ◽  
pp. 565-567 ◽  
Author(s):  
Tining Su ◽  
P. C. Taylor ◽  
Shenlin Chen ◽  
R. S. Crandall ◽  
A. H. Mahan
Keyword(s):  
Amorphous Silicon ◽  
Molecular Hydrogen ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogenated Amorphous

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.

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

2015 ◽  
Vol 1757 ◽  
Author(s):  
Parthapratim Biswas ◽  
David Alan Drabold
Keyword(s):  
Amorphous Silicon ◽  
First Principles ◽  
Molecular Hydrogen ◽  
Hydrogenated Amorphous Silicon ◽  
Experimental Information ◽  
Higher Order ◽  
Hydrogenated Amorphous

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.

Molecular Hydrogen in Hot-Wire Hydrogenated Amorphous Silicon

1998 ◽  
Vol 507 ◽  
Author(s):  
Xiao. Liu ◽  
E. Iwaniczko ◽  
R.O. Pohl ◽  
R.S. Crandall
Keyword(s):  
Internal Friction ◽  
Amorphous Silicon ◽  
Molecular Hydrogen ◽  
Solid Phase ◽  
Hydrogenated Amorphous Silicon ◽  
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

1996 ◽  
Vol 420 ◽  
Author(s):  
R. E. Norberg ◽  
P. A. Fedders ◽  
D. J. Leopold
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Amorphous Silicon ◽  
Molecular Hydrogen ◽  
Hydrogenated Amorphous Silicon ◽  
High Quality ◽  
Magnetic Resonance Studies ◽  
Structural Configurations ◽  
Species Specific ◽  
Hydrogenated Amorphous

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.

Structural Origin of Bulk Molecular Hydrogen in Hydrogenated Amorphous Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
Xiao Liu ◽  
R.O. Pohl ◽  
R.S. Crandall
Keyword(s):  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Triple Point ◽  
Vapor Deposition ◽  
Molecular Hydrogen ◽  
Bubble Formation ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Cold Worked ◽  
Hydrogenated Amorphous

AbstractThe elastic anomaly observed previously at the triple point of bulk molecular hydrogen in hydrogenated amorphous silicon films prepared by hot-wire chemical-vapor deposition has also been observed in deuterated films at the triple point of D2. The origin of this anomaly has now been traced to bubbles formed at the crystalline-amorphous interface. An upper limit of the pressure in these bubbles at their formation temperature, 440°C, has been estimated to be 11 MPa, and is suggested to be a measure of the bonding strength between film and substrate at that temperature. Bubble formation after heat treatment at 400°C has also been observed in films prepared by plasma-enhanced chemical-vapor deposition. The internal friction anomalies resemble those observed previously in cold-worked hydrogenated iron where they have been interpreted through plastic deformation of solid hydrogen in voids.

Molecular hydrogen in hydrogenated amorphous silicon: NMR evidence

2000 ◽  
Vol 62 (19) ◽  
pp. 12849-12858 ◽  
Author(s):  
T. Su ◽  
S. Chen ◽  
P. C. Taylor ◽  
R. S. Crandall ◽  
A. H. Mahan
Keyword(s):  
Amorphous Silicon ◽  
Molecular Hydrogen ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogenated Amorphous

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

High Rate Deposition of Stable Hydrogenated Amorphous Silicon in Transition from Amorphous to Microcrystalline Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Guofu Hou ◽  
Xinhua Geng ◽  
Xiaodan Zhang ◽  
Ying Zhao ◽  
Junming Xue ◽  
...  
Keyword(s):  
Phase Transition ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
High Rate ◽  
Very High Frequency ◽  
High Quality ◽  
Working Pressure ◽  
Hydrogen Dilution ◽  
Hydrogenated Amorphous

AbstractHigh rate deposition of high quality and stable hydrogenated amorphous silicon (a-Si:H) films were performed near the threshold of amorphous to microcrystalline phase transition using a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of hydrogen dilution on optic-electronic and structural properties of these films was investigated by Fourier-transform infrared (FTIR) spectroscopy, Raman scattering and constant photocurrent method (CPM). Experiment showed that although the phase transition was much influenced by hydrogen dilution, it also strongly depended on substrate temperature, working pressure and plasma power. With optimized condition high quality and high stable a-Si:H films, which exhibit σph/σd of 4.4×106 and deposition rate of 28.8Å/s, have been obtained.

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