Diffusion instability of homogeneous distribution of mercury in cadmium mercury telluride

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

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Author(s)

  • Mikhail I. Vasilevskiy
  • Enrique V. Anda

Detail(s)

Original languageEnglish
Pages (from-to)157-162
Journal / PublicationSemiconductor Science and Technology
Volume10
Issue number2
Publication statusPublished - Feb 1995
Externally publishedYes

Abstract

A mechanism of formation of inhomogeneities in the alloy CdxHg1-xTe during either post-growth cooling or low-temperature annealing is proposed, based on a diffusion instability in the interacting system which includes cations in lattice sites, mercury interstitials and cation vacancies. The principal points of the mechanism are: (i) vacancies follow local variations of alloy composition, being always in local equilibrium; (ii) their concentration depends superlinearly on local composition. The uniform distribution of composition and the native dopants becomes unstable under a condition that is likely to be satisfied at temperatures below 200 °C in samples enriched with mercury interstitials. We show that the instability should result in the formation of a 'layered' doping profile where the concentration of mercury interstitials varies by a factor of 2-3 while the variation of composition is of the order of 10%. Possible consequences of this effect for the electrophysical properties of the alloy are discussed.