Temperature dependence of the band gap of zinc nitride observed in photoluminescence measurements.

Alistair Kean, Aris Trapalis, Jon Heffernan, Ian Farrer, Jonathan Sharman

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We report the photoluminescence properties of DC sputtered zinc nitride thin films in the temperature range of 3.7–300 K. Zinc nitride samples grown at 150 °C exhibited a narrow photoluminescence band at 1.38 eV and a broad band at 0.90 eV, which were attributed to the recombination of free carriers with a bound state and deep-level defect states, respectively. The high-energy band followed the Varshni equation with temperature and became saturated at high excitation powers. These results indicate that the high-energy band originates from shallow defect states in a narrow bandgap. Furthermore, a red-shift of the observed features with increasing excitation power suggested the presence of inhomogeneities within the samples.
Zinc Nitride (Zn3N2) is a II-V semiconductor material whose properties are relatively little studied compared to materials used in commercial applications, such as III-V semiconductors. Because of the relative abundance of zinc compared to other metals and the use of non-toxic nitrogen, Zn3N2 is a candidate for the fabrication of low cost semiconductor devices such as low cost solar cells. However, further investigation of its basic material properties is necessary before the full potential of this material can be realized. The bandgap of Zn3N2 has been a controversial topic in published literatures,1,2 with reports ranging from 0.9 to 3.5 eV. Even though this is a very wide range, similar discrepancies have been reported in the early stages of other materials. For instance, the bandgap of InN was initially reported to be as high as 2.3 eV, but in later studies,3–7 it was found to have a much lower bandgap of 0.7 eV. Oxygen contamination was, among other effects, considered to be the cause behind the wide bandgap reports. Zn3N2 tends to oxidise at ambient conditions, which has complicated the unambiguous identification of its bandgap.
Original languageEnglish
Article number122105
JournalApplied Physics Letters
Volume111
Issue number12
DOIs
Publication statusPublished - 20 Sep 2017

Keywords

  • Zinc Nitride
  • Temperature
  • band gap

Fingerprint Dive into the research topics of 'Temperature dependence of the band gap of zinc nitride observed in photoluminescence measurements.'. Together they form a unique fingerprint.

  • Cite this