Defects induced broad spectral photoresponse of PVT-grown bulk AlN crystals

Abstract

Aluminum nitride (AlN) is a wide bandgap semiconductor with promising application prospect in deep ultraviolet optoelectronic devices. Here, bulk AlN crystals in millimeter size were grown using an improved physical vapor transport technique. Schottky diodes based on these crystals demonstrated good photoresponse to a broad spectral range from 261 nm to 1064 nm. The photoresponse is attributed to the defects induced midgap energy states. The device demonstrated a photo responsivity up to 3.7 AW−1 at 360 nm with bias voltage of −10 V. This research paves a new way for broad spectral photodetectors.