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Title: Iodine Doping of CdTe and CdMgTe for Photovoltaic Applications

Here, iodine-doped CdTe and Cd 1-xMg xTe layers were grown by molecular beam epitaxy. Secondary ion mass spectrometry characterization was used to measure dopant concentration, while Hall measurement was used for determining carrier concentration. Photoluminescence intensity and time-resolved photoluminescence techniques were used for optical characterization. Maximum n-type carrier concentrations of 7.4 x 10 18 cm -3 for CdTe and 3 x 10 17 cm -3 for Cd 0.65Mg 0.35Te were achieved. Studies suggest that electrically active doping with iodine is limited with dopant concentration much above these values. Dopant activation of about 80% was observed in most of the CdTe samples. The estimated activation energy is about 6 meV for CdTe and the value for Cd 0.65Mg 0.35Te is about 58 meV. Iodine-doped samples exhibit long lifetimes with no evidence of photoluminescence degradation with doping as high as 2 x 10 18 cm -3, while indium shows substantial non-radiative recombination at carrier concentrations above 5 x 10 16 cm -3. Iodine was shown to be thermally stable in CdTe at temperatures up to 600 °C. Results suggest iodine may be a preferred n-type dopant compared to indium in achieving heavily doped n-type CdTe.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1]
  1. Texas State Univ., San Marcos, TX (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. EAG Laboratories, Sunnyvale, CA (United States)
Publication Date:
Report Number(s):
NREL/JA-5K00-68892
Journal ID: ISSN 0361-5235
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Journal of Electronic Materials
Additional Journal Information:
Journal Volume: 46; Journal Issue: 9; Journal ID: ISSN 0361-5235
Publisher:
Springer
Research Org:
National Renewable Energy Lab. (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; CdTe; Cd1-xMgxTe; doping; iodine; MBE; solar cell
OSTI Identifier:
1374126