Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics

doi:10.1109/JPHOTOV.2017.2787021

Title: Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics

Abstract

Commercial CdTe PV modules have polycrystalline thin films deposited on glass, and devices made in this format have exceeded 22% efficiency. Devices made by the authors with a magnesium zinc oxide window layer and tellurium back contact have achieved efficiency over 18%, but these cells still suffer from an open-circuit voltage far below ideal values. Oxide passivation layers made by sputter deposition have the potential to increase voltage by reducing interface recombination. CdTe devices with these passivation layers were studied with photoluminescence (PL) emission spectroscopy and time-resolved photoluminescence (TRPL) to detect an increase in minority carrier lifetime. Because these oxide materials exhibit barriers to carrier collection, micropatterning was used to expose small point contacts while still allowing interface passivation. TRPL decay lifetimes have been greatly enhanced for thin polycrystalline absorber films with interface passivation. Device performance was measured and current collection was mapped spatially by light-beam-induced current.

Authors:

^[1];

^[1]; Williams, Desiree ^[1]; Kuciauskas, Darius ^[2]; Dippo, Pat ^[2]; Munshi, Amit ^[1]; Sampath, W. S. ^[1]

Colorado State Univ., Fort Collins, CO (United States)
National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:: 2018-01-18

Research Org.:: National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)

OSTI Identifier:: 1422874

Report Number(s):: NREL/JA-5900-70431
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: 8; Journal Issue: 2; Journal ID: ISSN 2156-3381

Publisher:: IEEE

Country of Publication:: United States

Language:: English

Subject:: 14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; passivation; II-VI semiconductor materials; cadmium compounds; aluminum oxide; sputtering; photovoltaic systems

Citation Formats


                    Kephart, Jason M., Kindvall, Anna, Williams, Desiree, Kuciauskas, Darius, Dippo, Pat, Munshi, Amit, and Sampath, W. S. Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics.  United States: N. p., 2018. 
        Web.  doi:10.1109/JPHOTOV.2017.2787021.

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                    Kephart, Jason M., Kindvall, Anna, Williams, Desiree, Kuciauskas, Darius, Dippo, Pat, Munshi, Amit, & Sampath, W. S. Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics.  United States.  doi:10.1109/JPHOTOV.2017.2787021.

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                    Kephart, Jason M., Kindvall, Anna, Williams, Desiree, Kuciauskas, Darius, Dippo, Pat, Munshi, Amit, and Sampath, W. S. Thu .  
        "Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics".  United States.  doi:10.1109/JPHOTOV.2017.2787021.  https://www.osti.gov/servlets/purl/1422874.

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@article{osti_1422874,

  title        = {Sputter-Deposited Oxides for Interface Passivation of CdTe Photovoltaics},

  author       = {Kephart, Jason M. and Kindvall, Anna and Williams, Desiree and Kuciauskas, Darius and Dippo, Pat and Munshi, Amit and Sampath, W. S.},

  abstractNote = {Commercial CdTe PV modules have polycrystalline thin films deposited on glass, and devices made in this format have exceeded 22% efficiency. Devices made by the authors with a magnesium zinc oxide window layer and tellurium back contact have achieved efficiency over 18%, but these cells still suffer from an open-circuit voltage far below ideal values. Oxide passivation layers made by sputter deposition have the potential to increase voltage by reducing interface recombination. CdTe devices with these passivation layers were studied with photoluminescence (PL) emission spectroscopy and time-resolved photoluminescence (TRPL) to detect an increase in minority carrier lifetime. Because these oxide materials exhibit barriers to carrier collection, micropatterning was used to expose small point contacts while still allowing interface passivation. TRPL decay lifetimes have been greatly enhanced for thin polycrystalline absorber films with interface passivation. Device performance was measured and current collection was mapped spatially by light-beam-induced current.},

  doi          = {10.1109/JPHOTOV.2017.2787021},

  journal      = {IEEE Journal of Photovoltaics},

  number       = 2,

  volume       = 8,

  place        = {United States},

  year         = {2018},

  month        = {1}

}

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Journal Article:

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DOI: 10.1109/JPHOTOV.2017.2787021

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Figures / Tables:

Figure 1: Low-temperature photoluminescence indicates no alloy broadening in CdTe for an MZO/CdTe device. This is evident from the exciton emission peak at 1.59 eV. Lower energy bands are related to defects.

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