Impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c-plane GaN/AlGaN quantum wells

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Abas Roble
  • Saroj Patra
  • Fabien Massabuau
  • M. Frentrup
  • Marina Leontiadou
  • Philip Dawson
  • M. J. Kappers
  • R. A. Oliver
  • Stefan Schulz

Abstract

We report on a combined theoretical and experimental study of the impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c-plane GaN/AlGaN multi-quantum well systems. The presence of carrier localization effects in this system was demonstrated by experimental observations, such as the “S-shape” temperature dependence of the photoluminescence (PL) peak energy, and non-exponential PL decay curves that varied across the PL spectra at 10 K. A three-dimensional modified continuum model, coupled with a self-consistent Hartree scheme, was employed to gain insight into the electronic and optical properties of the experimentally studied c-plane GaN/AlGaN quantum wells. This model confirmed the existence of strong hole localization arising from the combined effects of the built-in polarization field along the growth direction and the alloy fluctuations at the quantum well/barrier interface. However, for electrons these localization effects are less pronounced in comparison to the holes. Furthermore, our calculations show that the attractive Coulomb interaction between electron and hole results in exciton localization. This behavior is in contrast to the picture of independently localized electrons and holes, often used to explain the radiative recombination process in c-plane InGaN/GaN quantum well systems.

Bibliographical metadata

Original languageEnglish
Article number18862 (2019)
Pages (from-to)1-14
Number of pages14
JournalScientific Reports
Volume9
Early online date11 Dec 2019
DOIs
Publication statusPublished - 2020