GaN/Ga₂O₃ Avalanche Photodiodes with separate absorption and multiplication structure

This article proposes a new, to the best of our knowledge, separate absorption and multiplication (SAM) APD based on GaN/β-Ga2O3 heterojunction with high gains. The proposed APD achieved a high gain of 1.93 × 104. We further optimized the electric field distribution by simulating different doping concentrations and thicknesses of the transition region, resulting in the higher avalanche gain of the device. Furthermore, we designed a GaN/β-Ga2O3 heterojunction instead of the single Ga2O3 homogeneous layer as the multiplication region. Owing to the higher hole ionization coefficient, the device offers up to a 120% improvement in avalanche gain reach to 4.24 × 104. We subsequently clearly elaborated on the working principle and gain mechanism of GaN/β-Ga2O3 SAM APD. The proposed structure is anticipated to provide significant guidance for ultraweak ultraviolet light detection.