Characterization of AlGaN/GaN Metal- Semiconductor-Metal Photodetectors With a Low-Temperature AlGaN Interlayer

AlGaN/GaN metal-semiconductor-metal photodetectors (MSM PDs) with a low-temperature (LT) AlGaN interlayer (IL) were fabricated. Compared with the conventional AlGaN/GaN MSM PD, it was found that leakage current can be suppressed by insertion of a LT AlGaN IL due to the reduction of surface pits and improvement of crystalline quality. It was also found that larger photoresponsivity can be achieved due to the enhanced electric field strength as a result of inserting a LT AlGaN IL. Furthermore, suppressed photoconductive gain, lower noise level, and larger detectivity of MSM PD can also be achieved by using a LT AlGaN IL.