Stabilization of Wide Band-Gap p-Type Wurtzite MnTe Thin Films on Amorphous Substrates

Sebastian Siol, Yanbing Han, John Mangum, Philip Schulz, Aaron M. Holder, Talysa R. Klein, Maikel F.A.M. Van Hest, Brian Gorman, Andriy Zakutayev

Research output: Contribution to journalArticlepeer-review

22 Scopus Citations

Abstract

An important challenge in the development of optoelectronic devices for energy conversion applications is the search for suitable p-type contact materials. For example, p-type MnTe would be a promising alternative back contact for CdTe solar cells due to their chemical compatibility, but under normal conditions it has a too narrow band gap due to its octahedrally coordinated nickeline (NC) structure. The tetrahedrally coordinated wurtzite (WZ) polymorph of MnTe has not been reported, but it is especially interesting due to its predicted wider band gap and better structural compatibility with CdTe and related II-VI semiconductor materials. Here, we report on the stabilization of WZ-MnTe thin films on amorphous indium zinc oxide (a-IZO) substrates relevant to photovoltaic applications. Optical spectroscopy of the WZ-MnTe films shows a wide direct band gap of Eg = 2.7 eV, while photoelectron spectroscopy (PES) measurements reveal weak p-type doping with a Fermi level of 0.6 eV above the valence band maximum. The results of electron microscopy and PES measurements indicate that WZ-MnTe is stabilized due to interdiffusion at the interface with IZO. The results of this work introduce a substrate stabilized WZ-MnTe polymorph as a potential p-type contact material candidate for future applications in CdTe devices for solar energy conversion and other optoelectronic technologies.

Original languageAmerican English
Pages (from-to)6297-6304
Number of pages8
JournalJournal of Materials Chemistry C
Volume6
Issue number23
DOIs
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018 The Royal Society of Chemistry.

NREL Publication Number

  • NREL/JA-5K00-71393

Keywords

  • chemical stabilization
  • nickeline
  • photoelectron spectroscopy
  • polymorphism
  • sputtering
  • TEM
  • UPS
  • wurtzite
  • WZ-MnTe
  • XPS

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