Abstract: The growth,fabrication,and characterization of a solar-blind AlGaN-based p-i-n back-illuminated photodetector with a high temperature AlN template are reported for the first time.The photodetector was fabricated from multilayer AlxGa1-xN films grown by MOCVD on double-polished c-plane (0001) sapphire substrates.Crack free,high Al content (0.7) AlGaN multilayer structure,designed for the solar-blind p-i-n back-illuminated photodetector,was grown on a high temperature AlN template without a nuclear layer.The high quality of the epitaxial layers is demonstrated by in-situ optical reflectance monitoring curve,triple-axis X-ray diffraction,and atomic-force microscope.At a 1.8V bias,the processed p-i-n photodetector exhibits a solar-blind photoresponse with a maximum responsivity of 0.0864A/W at 270nm.The photodetector exhibits a forward turn-on voltage at around 3.5V and a reverse breakdown voltage above 20V,and the leakage current is below 20pA for 2V reverse bias.

Key words: solar-blind, high temperature AlN template, back-illuminated photodetector, p-i-n