Perspectives on future directions in III-N semiconductor research

The family of III-V nitride semiconductors has garnered significant research attention over the last 20–25 years, and these efforts have led to many highly successful technologies, especially in the area of light emitting devices such as light emitting diodes for solid state white lighting and lasers for high density optical read/write memories. These applications have taken advantage of a key material property of the III-N materials, namely a direct, tunable (0.7–6.2 eV, λ ∼ 200 nm to 1.7 μm) bandgap and have been accomplished despite a relatively poor level of material quality. But a direct, tunable bandgap is only one of many interesting properties of III-N materials of interest to potential future technologies. A considerable list of first and second order properties make this family of semiconductors even more attractive—namely, electric polarization, piezoelectricity, high breakdown field, pyroelectricity, electro-optic and photo-elastic effects, etc. The first few of these have found much utility in the development of high power transistors that promise significant commercial success in both communications and power switching applications. As these areas begin to flourish, it is reasonable to begin to explore what might be next for this versatile family of semiconductors. Here are highlighted three areas of significant potential for future III-N research—atomic layer epitaxy of complex heterostructures, variable polarity homo- and hetero-structures of arbitrary geometries, and nanowire heterostructures. Early results, key technical challenges, and the ultimate potential for future technologies are highlighted for each research path.