GaN-based tunnel junctions and optoelectronic devices grown by metal-organic vapor-phase epitaxy

This paper mainly describes the status and prospects of GaN-based tunnel junctions grown by metal-organic vapor-phase epitaxy. GaN-based tunnel junctions are expected to offer an alternative structure for hole injection in various optoelectronic devices, simultaneously providing additional features, such as electrical contacts between cascaded devices, current confinement, simple device fabrication processes, and novel controllability in band engineering. After reviewing the role of tunnel junctions and the history of the development of GaN-based tunnel junctions, the development details of GaInN, GaN, and AlGaN tunnel junctions are separately summarized, including those grown by molecular beam epitaxy. Various optoelectronic devices utilizing GaN-based tunnel junctions are reviewed from the viewpoint of device characteristics.