Compositional disordering of InGaAs/GaAs heterostructures by low-temperature-grown GaAs layers

J. S. Tsang*, C. P. Lee, S. H. Lee, K. L. Tsai, Chia-Ming Tsai, J. C. Fan

*Corresponding author for this work

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Compositional disordering of InGaAs/GaAs superlattices using a low-temperature-grown GaAs cap layer (LT-GaAs) by molecular beam epitaxy has been studied. The disordering of the superlattice was verified by photoluminescence and double-crystal x-ray rocking curve measurements. The Ga-vacancy-enhanced interdiffusion due to the presence of LT-GaAs was found to be the disordering mechanism. Diffusion equations and the Schrödinger's equation were solved numerically to obtain the composition profile and the transition energies in the disordered quantum well, respectively. The simulated energy shifts for samples under different annealing conditions agreed very well with the experimental results. The calculated effective diffusivity for the In-Ga interdiffusion has an activation energy of 1.63 eV, which is smaller than the activation energy 1.93 eV, for intrinsic interdiffusion. The diffusivity for the enhanced In-Ga interdiffusion due to the presence of LT-GaAs is about two orders of magnitude larger than the intrinsic In-Ga diffusivity.

Original languageEnglish
Pages (from-to)664-670
Number of pages7
JournalJournal of Applied Physics
Volume79
Issue number2
DOIs
StatePublished - 15 Jan 1996

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