Origins of bandgap bowing in compound-semiconductor common-cation ternary alloys

Nacir Tit, Ihab M. Obaidat, Hussain Alawadhi

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)

Abstract

We present an investigation into the existence and origins of bandgap bowing in compound-semiconductor common-cation ternary alloys. As examples, we consider CdSexTe1-x and ZnSe1-xTex alloys. A calculation, based on the sp3s* tight-binding method including spin-orbit coupling within the framework of the virtual crystal approximation, is employed to determine the bandgap energy, local density of states and atomic charge states versus composition and valence-band offset. The results show that (i)in the valence band, the top states are mainly contributed by Te atoms. The degree of ionicity of all atoms is found to vary linearly with mole fraction x. (ii)There is a strong competition between the anions (Se and Te) in trapping/losing charges and this competition is the main reason for the bandgap bowing character. (iii)There is a reasonable agreement between the calculated results and the available photoluminescence data. (iv)The bowing parameter is found to increase with increasing valence-band offset and increasing lattice mismatch.

Original languageEnglish
Article number075802
JournalJournal of Physics Condensed Matter
Volume21
Issue number7
DOIs
Publication statusPublished - Apr 9 2009

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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