Distinct light emission from two-dimensional electron gas at a lattice-matched InAlN/AlGaN heterointerface

Abstract

We report on distinct light emission from two-dimensional electron gas (2DEG) at a lattice-matched (LM) In0.12Al0.88N/Al0.21Ga0.79N heterointerface. The recombination between the electrons in the 2DEG in the ground state E1 and photoexcited holes in the Al0.21Ga0.79N layer was identified. In contrast to GaN channel-based heterostructures (HSs), larger activation energy of the 2DEG-related emission from LM In0.12Al0.88N/Al0.21Ga0.79N HS was obtained to be approximately 17 meV, which enables the distinguished 2DEG photoluminescence (PL) peak to be more thermally stable. Moreover, the existence of the 2DEG accelerates the reduction of the PL lifetime of the emission from Al0.21Ga0.79N. Compared to the general 2DEG PL feature with a broad recombination band in GaN channel-based HSs, the improved emission characteristics of the 2DEG in the In0.12Al0.88N/Al0.21Ga0.79N HS were attributed to electron localization in a deep triangular potential well, large 2DEG density induced by the In0.12Al0.88N layer, and the improvement of the interfacial crystal quality due to the lattice match between In0.12Al0.88N and Al0.21Ga0.79N layers. These findings provide important insight into understanding the InAlN-based HSs and will be potentially useful to advance the electronic and photonic applications for group-III nitrides.