Carrier localization mechanisms in In${}_{x}$Ga${}_{1\ensuremath{-}x}$N/GaN quantum wells

Carrier localization mechanisms in In $_{x}$ Ga $_{1 - x}$ N/GaN quantum wells

D. Watson-Parris, M. J. Godfrey, P. Dawson, R. A. Oliver, M. J. Galtrey, M. J. Kappers, and C. J. Humphreys

Phys. Rev. B 83, 115321 – Published 16 March 2011

Abstract

Localization lengths of the electrons and holes in InGaN/GaN quantum wells have been calculated using numerical solutions of the effective mass Schrödinger equation. We have treated the distribution of indium atoms as random and found that the resultant fluctuations in alloy concentration can localize the carriers. By using a locally varying indium concentration function we have calculated the contribution to the potential energy of the carriers from band gap fluctuations, the deformation potential, and the spontaneous and piezoelectric fields. We have considered the effect of well width fluctuations and found that these contribute to electron localization, but not to hole localization. We also simulate low temperature photoluminescence spectra and find good agreement with experiment.