Theoretical analysis of unstable two-phase region and microscopic structure in wurtzite and zinc-blende InGaN using modified valence force field model

Toru Takayama, Masaaki Yuri, Kunio Itoh, Takaaki Baba, James S. Harris

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38 Citations (Scopus)

Abstract

A model to predict material characteristics of the InGaN ternary system, which is useful for blue and green light emitting and laser diodes, with respect to an unstable two-phase region in the phase field and the first neighbor anion-cation bond length is developed. The unstable region is analyzed using a strictly regular solution model. The interaction parameter used in the analysis is obtained from a strain energy calculation using the valence force field (VFF) model, modified for both wurtzite and zinc-blende structures to avoid overestimation of the strain energy. The structural deviation from an ideal wurtzite structure in GaN and InN is also taken into account in our model. The critical temperatures found in our analysis for wurtzite InGaN and zinc-blende InGaN are 1967 and 1668 K, respectively. This suggests that, at typical growth temperatures around 800 °C, a wide unstable two-phase region exists in both wurtzite and zinc-blende structures. The modified VFF model can also predict the microscopic crystal structure, such as first neighbor anion-cation bond lengths. In order to validate our calculation results for zinc-blende structures, we compare the calculated and the experimental results in terms of the interaction parameter and the first neighbor anion-cation bond lengths in the InGaAs system. For the wurtzite structure, we compare the calculated and the experimental results for the first neighbor anion-cation bond lengths in the InGaN system. The calculated results agree well with the experimental results.

Original languageEnglish
Pages (from-to)1104-1110
Number of pages7
JournalJournal of Applied Physics
Volume88
Issue number2
Publication statusPublished - 2000 Jul 15
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)

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