Deep Level and Near-Band-Edge Recombination in Semiconducting Antiperovskite Hg3Se2I2 Single Crystals

Sanjib Das, Kyle M. McCall, John A. Peters, Yihui He, Joon Il Kim, Zhifu Liu, Mercouri G. Kanatzidis, Bruce W. Wessels*

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

The wide-bandgap, semiconducting ternary compound Hg3Se2I2 has shown promise as room-temperature hard-radiation detector. Since this compound was first reported, there has been significant improvement in crystal growth using a chemical vapor transport method with a polyethylene growth agent. To study the effects of this additional precursor on crystal quality, the nature of radiative and nonradiative defects using photoluminescence (PL) and photocurrent (PC) studies of Hg3Se2I2 single crystals are investigated. In contrast to earlier studies, excitation intensity-dependence of PL emission shows that the near-band-edge (NBE) emission bands are all excitonic in nature. The PL intensity decreases with increasing temperature, with the higher energy peaks quenching by 40 K and the deeper levels quenched after 110 K. The PC spectra show a complex structure at room temperature related to NBE transitions in the band structure, while at low temperature only the direct gap transition is observed due to phonons freezing out. The PC spectra at low temperature also indicate several midgap levels that are attributed to native defects within the bulk crystal. These results indicate that the high quality of Hg3Se2I2 single crystals is maintained when the transport agent is used during growth, although there are still a variety of defects present.

Original languageEnglish (US)
Article number1800328
JournalAdvanced Optical Materials
Volume6
Issue number22
DOIs
StatePublished - Nov 19 2018

Keywords

  • photocurrent spectroscopy
  • photoluminescence
  • wide-bandgap semiconductors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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