Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells

doi:10.1021/acsami.9b12703

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Title: Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells

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Abstract

In this study, substochiometric hole-selective molybdenum oxide (MoO _x) contacts in crystalline silicon (c-Si) solar cells were investigated by a combination of transmission electron microscopy (TEM) and spatially resolved electron energy-loss spectroscopy (SR-EELS). It was observed that a ≈ 4 nm SiO _x interlayer grows at the MoO _x/c-Si interface during the evaporation of MoO _x over a c-Si substrate. SR-EELS analyses revealed the presence of a 1.5 nm diffused MoO _x/indium tin oxide (ITO) interface in both as-deposited and annealed samples. Moreover, the presence of a 1 nm thin layer with a lower oxidation state of Mo was detected at the SiO _x/MoO _x interface in an as-deposited state, which disappears upon annealing. Altogether, it was evident that no hole-blocking interlayer is formed at the MoO _x/ITO interface during annealing and homogenization of the MoO _x layer takes place during the annealing process. Furthermore, device simulations revealed that efficient hole collection is dependent on MoO _x work function and that reduction in the work function of MoO _x results in loss of band bending and negatively impacts hole selectivity.

Authors:

Ali, Haider ^[1]; Maynau, Céline ^[2];

^[2]; Gregory, Geoffrey ^[1];

^[3]; Looney, John Patrick ^[3];

^[3]; Schneider, Matthew ^[4]; Schoenfeld, Winston V. ^[1];

^[1]

Univ. of Central Florida, Orlando, FL (United States)
Univ. de Cádiz (Spain)
Brookhaven National Lab. (BNL), Upton, NY (United States)
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States

Publication Date:: 2019-10-31

Research Org.:: Brookhaven National Lab. (BNL), Upton, NY (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)

OSTI Identifier:: 1583109

Report Number(s):: BNL-213528-2020-JAAM
Journal ID: ISSN 1944-8244

Grant/Contract Number:: SC0012704; EE0007533

Resource Type:: Accepted Manuscript

Journal Name:: ACS Applied Materials and Interfaces

Additional Journal Information:: Journal Volume: 11; Journal Issue: 46; Journal ID: ISSN 1944-8244

Publisher:: American Chemical Society (ACS)

Country of Publication:: United States

Language:: English

Subject:: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; hole-selective; molybdenum oxide (MoOx); transmission electron microscopy (TEM); electron energy-loss spectroscopy (EELS); silicon

Citation Formats


                    Ali, Haider, Maynau, Céline, Lajaunie, Luc, Gregory, Geoffrey, Wu, Lijun, Looney, John Patrick, Zhu, Yimei, Schneider, Matthew, Schoenfeld, Winston V., and Davis, Kristopher O. Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells.  United States: N. p., 2019. 
        Web.  doi:10.1021/acsami.9b12703.

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                    Ali, Haider, Maynau, Céline, Lajaunie, Luc, Gregory, Geoffrey, Wu, Lijun, Looney, John Patrick, Zhu, Yimei, Schneider, Matthew, Schoenfeld, Winston V., & Davis, Kristopher O. Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells.  United States.  doi:10.1021/acsami.9b12703.

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                    Ali, Haider, Maynau, Céline, Lajaunie, Luc, Gregory, Geoffrey, Wu, Lijun, Looney, John Patrick, Zhu, Yimei, Schneider, Matthew, Schoenfeld, Winston V., and Davis, Kristopher O. Thu .  
        "Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells".  United States.  doi:10.1021/acsami.9b12703.

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@article{osti_1583109,

  title        = {Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells},

  author       = {Ali, Haider and Maynau, Céline and Lajaunie, Luc and Gregory, Geoffrey and Wu, Lijun and Looney, John Patrick and Zhu, Yimei and Schneider, Matthew and Schoenfeld, Winston V. and Davis, Kristopher O.},

  abstractNote = {In this study, substochiometric hole-selective molybdenum oxide (MoOx) contacts in crystalline silicon (c-Si) solar cells were investigated by a combination of transmission electron microscopy (TEM) and spatially resolved electron energy-loss spectroscopy (SR-EELS). It was observed that a ≈ 4 nm SiOx interlayer grows at the MoOx/c-Si interface during the evaporation of MoOx over a c-Si substrate. SR-EELS analyses revealed the presence of a 1.5 nm diffused MoOx/indium tin oxide (ITO) interface in both as-deposited and annealed samples. Moreover, the presence of a 1 nm thin layer with a lower oxidation state of Mo was detected at the SiOx/MoOx interface in an as-deposited state, which disappears upon annealing. Altogether, it was evident that no hole-blocking interlayer is formed at the MoOx/ITO interface during annealing and homogenization of the MoOx layer takes place during the annealing process. Furthermore, device simulations revealed that efficient hole collection is dependent on MoOx work function and that reduction in the work function of MoOx results in loss of band bending and negatively impacts hole selectivity.},

  doi          = {10.1021/acsami.9b12703},

  journal      = {ACS Applied Materials and Interfaces},

  number       = 46,

  volume       = 11,

  place        = {United States},

  year         = {2019},

  month        = {10}

}

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