A Solar-Blind AlGaN-Based p-i-n Back-Illuminated Photodetector with a High Temperature AlN Template Layer
高温AlN为模板的AlGaN基p-i-n背照式日光盲探测器

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 Alx Ga1-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.