A comparative study of AlGaN-based PiN type UV photodiodes with and without surface recessed structures

Abstract

We report on the fabrication and characterization of AlGaN-based PiN type UV photodiodes with and without the surface recessed electrode structures. It was confirmed that the device with the surface recessed structure showed a much higher responsivity of 202 mA/W at a wavelength of 272 nm under a reverse bias voltage of -5 V than that of the device without the surface structure. This responsivity corresponds to external quantum efficiency as high as 92%.