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Title: Structural stability and electronic properties of low-index surfaces of SnS

Thin film photovoltaic cells are increasingly important for cost-effective solar energy harvesting. Layered SnS is a promising absorber material due to its high optical absorption in the visible and good doping characteristics. We use first-principles calculations based on density functional theory to study structures of low-index surfaces of SnS using stoichiometric and oxygen-containing structural models, in order to elucidate their possible effect on the efficiency of the photovoltaic device. We find that the surface energy is minimized for the surface with orientation parallel to the layer stacking direction. Compared to stoichiometric surfaces, the oxygen-containing surfaces exhibit fewer electronic states near the band gap. This reduction of near-gap surface states by oxygen should reduce recombination losses at grain boundaries and interfaces of the SnS absorber, and should be beneficial to the efficiency of the solar cell.
Authors:
;  [1] ;  [1] ;  [2]
  1. School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22273468
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; GRAIN BOUNDARIES; INDEXES; INTERFACES; OXYGEN; PHASE STABILITY; PHOTOVOLTAIC EFFECT; RECOMBINATION; SOLAR CELLS; SOLAR ENERGY; STRUCTURAL MODELS; SURFACE ENERGY; SURFACES; THIN FILMS; TIN SULFIDES