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This content will become publicly available on February 20, 2017

Title: Dependence of short and intermediate-range order on preparation in experimental and modeled pure a-Si

Variability in the short-to-intermediate range order of pure amorphous silicon prepared by different experimental and computational techniques is probed by measuring mass density, atomic coordination, bond-angle deviation, and dihedral angle deviation. It is found that there is significant variability in order parameters at these length scales in this archetypal covalently bonded, monoatomic system. This diversity strongly reflects preparation technique and thermal history in both experimental and simulated systems. Experiment and simulation do not fully quantitatively agree, partly due to differences in the way parameters are accessed. However, qualitative agreement in the trends is identified. Relaxed forms of amorphous silicon closely resemble continuous random networks generated by a hybrid method of bond-switching Monte Carlo and molecular dynamics simulation. As-prepared ion implanted amorphous silicon can be adequately modeled using a structure generated from amorphization via ion bombardement using energetic recoils. Preparation methods which narrowly avoid crystallization such as experimental pressure-induced amorphization or simulated melt-quenching result in inhomogeneous structures that contain regions with significant variations in atomic ordering. Ad hoc simulated structures containing small (1 nm) diamond cubic crystal inclusions were found to possess relatively high bond-angle deviations and low dihedral angle deviations, a trend that could not be reconciled with any experimentalmore » material.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [4] ;  [2] ;  [2] ;  [5] ;  [5]
  1. Univ. of Helsinki, Helsinki (Finland); Univ. College London, London (United Kingdom); Aalto Univ., Espoo (Finland)
  2. Australian National Univ., Canberra (Australia)
  3. Univ. of Helsinki, Helsinki (Finland)
  4. Instituto de Nanociencia de Aragón, Universidad de Zaragoza, Zaragoza, 50009 Spain
  5. Monash Univ., Clayton (Australia)
Publication Date:
OSTI Identifier:
1241460
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Non-Crystalline Solids
Additional Journal Information:
Journal Volume: 438; Journal Issue: C; Journal ID: ISSN 0022-3093
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; 36 MATERIALS SCIENCE