Temperature dependent vibrational spectra in non-crystalline materials: application to hydrogenated amorphous silicon

We present a novel approach for parameter-free modeling of the structural, dynamical and electronic properties of non-crystalline materials based on ab-initio Molecular Dynamics, improved signal processing technique and computer visualization. The method have been extensively tested by investigating...

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Bibliographic Details
Published in:arXiv.org 2007-11
Main Authors: Kupchak, I M, Gaspari, F, Shkrebtii, A I, Perz, J
Format: Article
Language:English
Subjects:
Amorphous materials
Amorphous silicon
Crystal structure
Crystallinity
Hydrogen
Hydrogen storage
Hydrogen-based energy
Hydrogenation
Migration
Molecular dynamics
Signal processing
Silicon wafers
Stability analysis
Structural stability
Temperature dependence
Test procedures
Vibrational spectra
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Summary:We present a novel approach for parameter-free modeling of the structural, dynamical and electronic properties of non-crystalline materials based on ab-initio Molecular Dynamics, improved signal processing technique and computer visualization. The method have been extensively tested by investigating hydrogen and silicon dynamics in hydrogenated amorphous silicon (a-Si:H). By comparing the theoretical and experimental vibrational spectra we demonstrate how to relate vibrational properties to the structural stability, bonding and hydrogen diffusion. We extracted microscopic characteristics that cannot be obtained by other techniques, namely hydrogen migration and related bond switching, dangling bond passivation, low hydrogen activation energy, and a-Si:H stability in general, and we show, via the analysis of a test case, that our method provides a rigorous and realistic description of non-crystalline materials. We also demonstrate that this method offers the possibility of accessing other important macroscopic characteristics of amorphous silicon and can be used to model all the aspects of a-Si:H dynamics, including the detrimental Staebler-Wronski effect.
ISSN:2331-8422
DOI:10.48550/arxiv.0711.0912