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Title: Effect of intermixing at CdS/CdTe interface on defect properties

We investigated the stability and electronic properties of defects in CdTe 1- xSx that can be formed at the CdS/CdTe interface. As the anions mix at the interface, the defect properties are significantly affected, especially those defects centered at cation sites like Cd vacancy, VCd, and Te on Cd antisite, TeCd, because the environment surrounding the defect sites can have different configurations. We show that at a given composition, the transition energy levels of VCd and TeCd become close to the valence band maximum when the defect has more S atoms in their local environment, thus improving the device performance. Such beneficial role is also found at the grain boundaries when the Te atom is replaced by S in the Te-Te wrong bonds, reducing the energy of the grain boundary level. On the other hand, the transition levels with respect to the valence band edge of CdTe 1- xSx increases with the S concentration as the valence band edge decreases with the S concentration, resulting in the reduced p-type doping efficiency.
Authors:
 [1] ;  [1] ;  [1] ;  [2]
  1. National Renewable Energy Laboratory, Golden, Colorado 80401, USA
  2. Beijing Computational Science Research Center, Beijing 100094, China
Publication Date:
OSTI Identifier:
1293800
Report Number(s):
NREL/JA-5K00-66931
Journal ID: ISSN 0003-6951
DOE Contract Number:
AC36-08GO28308
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 4
Publisher:
American Institute of Physics (AIP)
Research Org:
NREL (National Renewable Energy Laboratory (NREL), Golden, CO (United States))
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS bond formation; II-VI semiconductors; band gap; defect levels; Jahn Teller effect