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Stable magnesium zinc oxide by reactive Co-Sputtering for CdTe-based solar cells

journal contribution
posted on 21.01.2021, 15:46 by Yegor Samoilenko, Gavin Yeung, Amit H Munshi, Ali Abbas, Carey L Reich, Michael Walker, Matthew O Reese, Andriy Zakutayev, Michael Walls, Walajabad S Sampath, Colin A Wolden
© 2020 Magnesium zinc oxide (MZO) is a promising front contact material for CdTe solar cells. Due to its higher band gap than traditional CdS, MZO can reduce parasitic absorption to significantly increase short-circuit current density while also providing a benefit of conduction band offset tuning through Mg:Zn ratio optimization. MZO has been successfully implemented into CdTe devices, however its stability has been of concern. The MZO stability issue has been attributed to the presence of oxygen in the CdTe device processing ambient, leading to double-diode behavior (S-kink) in the current density-voltage curves. Here we report on MZO thin films deposited by reactive co-sputtering. The reactively co-sputtered MZO thin films have encouraging stability, show no significant variation in work function of the surface over a period of 6 months, as measured by Kelvin probe. Energy conversion efficiencies of around 16% have been achieved both with and without presence of oxygen in device processing ambients across multiple research facilities. These efficiencies should be possible to increase further by tuning of the thin film deposition and device processing parameters, especially through optimization of the back contact.

Funding

National Science Foundation (NSF) through award number CBET-1706149

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Research Unit

  • Centre for Renewable Energy Systems Technology (CREST)

Published in

Solar Energy Materials and Solar Cells

Volume

210

Publisher

Elsevier BV

Version

VoR (Version of Record)

Rights holder

© Elsevier

Publisher statement

This paper was accepted for publication in the journal Solar Energy Materials and Solar Cells and the definitive published version is available at https://doi.org/10.1016/j.solmat.2020.110521

Acceptance date

16/03/2020

Publication date

2020-03-27

Copyright date

2020

ISSN

0927-0248

eISSN

1879-3398

Language

en

Depositor

Prof Michael Walls Deposit date: 19 January 2021

Article number

110521

Exports