Effects of the host conduction band energy on the electronic band structure of ZnCdTeO dilute oxide alloys

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • M. Welna
  • L. Janicki
  • W. M. Linhart
  • T. Tanaka
  • R. Kudrawiec
  • W. Walukiewicz

Related Research Unit(s)

Detail(s)

Original languageEnglish
Article number083106
Journal / PublicationJournal of Applied Physics
Volume126
Issue number8
Online published26 Aug 2019
Publication statusPublished - 28 Aug 2019

Abstract

Interband optical transitions in highly mismatched ZnTe1-xOx and Zn1-yCdyTe1-xOx alloys with Cd content y = 0.1 and 0.32 and oxygen content x < 0.016 grown on ZnTe substrates were studied by photoreflectance (PR) and photoluminescence (PL) in a broad temperature range. The incorporation of oxygen into a Zn(Cd)Te matrix results in a splitting of the conduction band (CB) into two E- and E+ subbands forming a semiconductor with an intermediate band. In ZnTeO, only the E- band could be probed by PR and there was no PL signal. An addition of Cd atoms to form a ZnCdTeO quaternary alloy significantly improves the optical quality as evidenced by an emergence of an E+ related transition in the PR spectra and the appearance of a PL emission related to the E- band visible up to 260 K. Moreover, for Cd content above 25%, a change in the E- band character is observed from localized O-like to CB-like. The analysis of a PR signal shows a strong reduction of the temperature dependence of the energy gap of Zn(Cd)TeO alloys compared to ZnTe. The temperature related reduction of the bandgap shift with increasing O content is well explained by the band anticrossing interaction between the temperature dependent conduction band of the host Zn(Cd)Te matrix and the temperature independent energy of highly localized O states.

Citation Format(s)

Effects of the host conduction band energy on the electronic band structure of ZnCdTeO dilute oxide alloys. / Welna, M.; Janicki, L.; Linhart, W. M.; Tanaka, T.; Yu, K. M.; Kudrawiec, R.; Walukiewicz, W.

In: Journal of Applied Physics, Vol. 126, No. 8, 083106, 28.08.2019.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal