Photoluminescence related to the two-dimensional electron gas at a GaN/AlGaN heterointerface

Abstract

We report photoluminescence (PL) spectra related to a two-dimensional electron gas confined at a GaN/AlGaN heterointerface. The recombination between electrons confined in the bottom of the interface potential and photoexcited holes causes a broad PL emission about 50 meV below the GaN exciton emissions. A second emission, attributed to the recombination of electrons in the first excited level at the interface, is also observed close to the excitonic band gap in GaN. The data agree with a self-consistent calculation of the energy levels and electron concentration at the interface.