Theoretical studies of structure and doping of hydrogenated amorphous silicon

Bin Cai, D. A. Drabold

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In a-Si:H, large concentrations of B or P (of order 1%) are required to dope the material, suggesting that doping mechanisms are very different than for the crystal for which much smaller concentrations are required. In this paper, we report simulations on B and P introduced into realistic models of a-Si:H and a-Si, with concentrations ranging from 1.6% to 12.5% of B or P in the amorphous host. The results indicate that tetrahedral B and P are effective doping configurations in a-Si, but high impurity concentrations introduce many defect states. For a-Si:H, we report that both B(3,1) and P(3,1) (B or P atom bonded with three Si atoms and one H atom) are effective doping configurations. We investigate H passivation in both cases. For both B and P, there exists a "hydrogen poison range" of order 6 Å for which H in a bond-center site can suppress doping. For B doping, nearby H prefers to stay at the bond-center of Si-Si, leaves B four-fold and neutralizes the doping configuration; for P doping, nearby H spoils the doping by inducing a reconstruction rendering initially tetrahedral P three-fold.

Original languageEnglish (US)
Title of host publicationAmorphous and Polycrystalline Thin-Film Silicon Science and Technology - 2011
Pages297-305
Number of pages9
DOIs
StatePublished - 2012
Externally publishedYes
Event2011 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 25 2011Apr 29 2011

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1321
ISSN (Print)0272-9172

Conference

Conference2011 MRS Spring Meeting
Country/TerritoryUnited States
CitySan Francisco, CA
Period4/25/114/29/11

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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