GaN MSM photodetectors with a semi-insulating alinn cap layer and sputtered ITO transparent electrodes

We propose a way to enhance the performance of the GaN-based UV metal-semiconductor-metal (MSM) photodetectors by jointly incorporating a semi-insulating AlInN cap layer with a sputtered indium tin oxide (ITO) electrode. The results show that a dark current as low as 1.49× 10-8 A/ cm₂ can be achieved via the insertion of highly resistive AlInN cap layers. A UV-to-visible rejection ratio as high as 28,306 with a 5 V applied bias can also be realized with this design. Furthermore, a much reduced noise-equivalent power of 2.85× 10-14 W and a rather high normalized detectivity of 2.15× 1013 cm Hz0.5 W-1 are also realized when the ITO electrode is used.