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Title: Enhanced p-Type Doping in Polycrystalline CdTe Films: Deposition and Activation

Abstract

An in situ nonequilibrium method to increase hole density in polycrystalline CdTe thin films to 10 16 cm -3 using group V substitution on Te is presented. Single-phase CdTe films doped with P, As, and Sb were deposited at 550 degrees C at 100-200 nm/s onto moving cadmium sulfide/high resistance transparent buffer layer/transparent conductive oxide /glass superstrates by vapor transport deposition in Cd overpressure from high purity compound sources. Doping levels before and after activation were determined by capacitance-voltage analysis of diagnostic devices. Secondary ion mass spectrometry depth profiling confirmed dopant incorporation levels of 10 17 -10 18 atoms/cm 3 in as-deposited films. Electronic activation was carried out by post-deposition annealing in Cd or CdCl 2 vapor with fast cooling, increasing acceptor concentrations to >10 15 cm -3 for P and >10 16 cm -3 for As and Sb, compared with mid -10 14 cm -3 acceptor levels for undoped CdTe films. The activation methods are compatible with post-deposition processing presently used for high-efficiency CdTe solar cells. For the dopants As and Sb, the acceptor concentration increased by substitutional As Te and Sb Te formation, respectively, which was validated by cathodoluminescence spectroscopy.

Authors:
 [1];  [1];  [1];  [1];  [2];  [2];  [2];  [2];  [2];  [2]
  1. Univ. of Delaware, Newark, DE (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1514851
Report Number(s):
NREL/JA-5K00-73937
Journal ID: ISSN 2156-3381
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
IEEE Journal of Photovoltaics
Additional Journal Information:
Journal Volume: 9; Journal Issue: 3; Journal ID: ISSN 2156-3381
Publisher:
IEEE
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; CdTe; doping; photovoltaic; thin film

Citation Formats

McCandless, Brian, Buchanan, Wayne, Sriramagiri, Gowri, Thompson, Christopher, Duenow, Joel N., Albin, David S., Jensen, Soeren A., Moseley, John, Al-Jassim, Mowafak M., and Metzger, Wyatt K. Enhanced p-Type Doping in Polycrystalline CdTe Films: Deposition and Activation. United States: N. p., 2019. Web. doi:10.1109/JPHOTOV.2019.2902356.
McCandless, Brian, Buchanan, Wayne, Sriramagiri, Gowri, Thompson, Christopher, Duenow, Joel N., Albin, David S., Jensen, Soeren A., Moseley, John, Al-Jassim, Mowafak M., & Metzger, Wyatt K. Enhanced p-Type Doping in Polycrystalline CdTe Films: Deposition and Activation. United States. doi:10.1109/JPHOTOV.2019.2902356.
McCandless, Brian, Buchanan, Wayne, Sriramagiri, Gowri, Thompson, Christopher, Duenow, Joel N., Albin, David S., Jensen, Soeren A., Moseley, John, Al-Jassim, Mowafak M., and Metzger, Wyatt K. Wed . "Enhanced p-Type Doping in Polycrystalline CdTe Films: Deposition and Activation". United States. doi:10.1109/JPHOTOV.2019.2902356. https://www.osti.gov/servlets/purl/1514851.
@article{osti_1514851,
title = {Enhanced p-Type Doping in Polycrystalline CdTe Films: Deposition and Activation},
author = {McCandless, Brian and Buchanan, Wayne and Sriramagiri, Gowri and Thompson, Christopher and Duenow, Joel N. and Albin, David S. and Jensen, Soeren A. and Moseley, John and Al-Jassim, Mowafak M. and Metzger, Wyatt K.},
abstractNote = {An in situ nonequilibrium method to increase hole density in polycrystalline CdTe thin films to 1016 cm-3 using group V substitution on Te is presented. Single-phase CdTe films doped with P, As, and Sb were deposited at 550 degrees C at 100-200 nm/s onto moving cadmium sulfide/high resistance transparent buffer layer/transparent conductive oxide /glass superstrates by vapor transport deposition in Cd overpressure from high purity compound sources. Doping levels before and after activation were determined by capacitance-voltage analysis of diagnostic devices. Secondary ion mass spectrometry depth profiling confirmed dopant incorporation levels of 1017 -1018 atoms/cm3 in as-deposited films. Electronic activation was carried out by post-deposition annealing in Cd or CdCl2 vapor with fast cooling, increasing acceptor concentrations to >1015 cm-3 for P and >1016 cm-3 for As and Sb, compared with mid -1014 cm-3 acceptor levels for undoped CdTe films. The activation methods are compatible with post-deposition processing presently used for high-efficiency CdTe solar cells. For the dopants As and Sb, the acceptor concentration increased by substitutional As Te and Sb Te formation, respectively, which was validated by cathodoluminescence spectroscopy.},
doi = {10.1109/JPHOTOV.2019.2902356},
journal = {IEEE Journal of Photovoltaics},
issn = {2156-3381},
number = 3,
volume = 9,
place = {United States},
year = {2019},
month = {3}
}

Journal Article:
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