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

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.

doi:10.1109/JPHOTOV.2019.2902356

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

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Abstract

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.

Authors:

McCandless, Brian ^[1]; Buchanan, Wayne ^[1]; Sriramagiri, Gowri ^[1]; Thompson, Christopher ^[1]; Duenow, Joel N. ^[2]; Albin, David S. ^[2]; Jensen, Soeren A. ^[2]; Moseley, John ^[2]; Al-Jassim, Mowafak M. ^[2]; Metzger, Wyatt K. ^[2]

Univ. of Delaware, Newark, DE (United States)
National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:: Wed Mar 20 00:00:00 EDT 2019

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:: 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.

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                    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.  https://doi.org/10.1109/JPHOTOV.2019.2902356

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                    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.  https://doi.org/10.1109/JPHOTOV.2019.2902356.  https://www.osti.gov/servlets/purl/1514851.

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@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},

  number       = 3,

  volume       = 9,

  place        = {United States},

  year         = {Wed Mar 20 00:00:00 EDT 2019},

  month        = {Wed Mar 20 00:00:00 EDT 2019}

}

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