Optical and electrical characterization of AlGaN based Schottky photodiodes after annealing at different temperatures

Abstract

In this study a comparison is made between the optical and electrical properties of Ni/Au and Ni/Ir/Au Schottky photodiodes based on Al0.35Ga0.65N. The effects of inserting Ir between Ni and Au are of particular interest. The comparison in the properties is done after annealing the photodiodes at different temperatures in an argon gas ambient. The reverse current decreased with annealing temperature up to 400 oC for the Ni/Au Schottky photodiode and up to 500 oC for the Ni/Ir/Au photodiode. The Schottky barrier heights increased with increasing annealing temperature. The responsivity of the Ni/Au photodiode was higher than that of the Ni/Ir/Au photodiode. The transmission of the Ni/Au metal layer improved with increasing annealing temperature up to 500 oC and the best transmission of the Ni/Ir/Au metal layer was after 400 oC annealing.