The 310-340 nm ultraviolet light emitting diodes grown using a thin GaN interlayer on a high temperature AlN buffer

Previously, we reported that a thin GaN interlayer approach has been developed for growth of 340 nm ultraviolet light emitting diodes (UV-LEDs) with significantly improved performance. In this paper, more recent results on the further development of UV-LEDs with shorter wavelengths are reported, and the limitation of the wavelength of the UV-LEDs that can be pushed to, while retaining high device performance using the approach has been investigated. Transmission electron microscopy and device-performance data, including electrical and optical characteristics, indicated that the thin GaN interlayer approach can be effectively employed for growth of UV-LEDs to an emission wavelength approaching at least 300 nm. The approach should be taken into account in growth of UV-LEDs on sapphire substrates, as it provides a simple but effective growth method to achieve UV-LEDs with high performance. This paper also reports that a micro-LED array using the UV-LED wafer has been successfully fabricated, offering versatile micro-structured UV light sources for a wide range of applications.