GaN MSM Photodetectors with a Semi-Insulating AlInN Cap Layer and Sputtered ITO Transparent Electrodes

摘要

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 x 10(-8) A/cm(2) 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 x 10(-14) W and a rather high normalized detectivity of 2.15 x 10(13) cm Hz(0.5) W-1 are also realized when the ITO electrode is used.