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

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:
 [1];  [2]; ORCiD logo [2];  [1]; ORCiD logo [3];  [3]; ORCiD logo [3];  [4];  [1]; ORCiD logo [1]
  1. Univ. of Central Florida, Orlando, FL (United States)
  2. Univ. de Cádiz (Spain)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
Publication Date:
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.
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.
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.
@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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This content will become publicly available on October 31, 2020
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