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Title: Defect properties of Sb- and Bi-doped CuInSe{sub 2}: The effect of the deep lone-pair s states

Bi or Sb doping has been used to make better material properties of polycrystalline Cu{sub 2}(In,Ga)Se{sub 2} as solar cell absorbers, including the experimentally observed improved electrical properties. However, the mechanism is still not clear. Using first-principles method, we investigate the stability and electronic structure of Bi- and Sb-related defects in CuInSe{sub 2} and study their effects on the doping efficiency. Contrary to previous thinking that Bi or Sb substituted on the anion site, we find that under anion-rich conditions, the impurities can substitute on cation sites and are isovalent to In because of the formation of the impurity lone pair s states. When the impurities substitute for Cu, the defects act as shallow double donors and help remove the deep In{sub Cu} level, thus resulting in the improved carrier life time. On the other hand, under anion-poor conditions, impurities at the Se site create amphoteric deep levels that are detrimental to the device performance.
Authors:
; ; ;  [1]
  1. National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
Publication Date:
OSTI Identifier:
22395566
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 24; 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; ANIONS; CATIONS; COPPER COMPOUNDS; DOPED MATERIALS; EFFICIENCY; ELECTRICAL PROPERTIES; ELECTRONIC STRUCTURE; GALLIUM SELENIDES; INDIUM SELENIDES; PERFORMANCE; PHASE STABILITY; POLYCRYSTALS