Low-noise GaN ultraviolet p-i-n photodiodes on GaN substrates

作者：Zhang Yun; Shen Shyh Chiang^*; Kim Hee Jin; Choi Suk; Ryou Jae Hyun; Dupuis Russell D; Narayan Bravishma

来源：Applied Physics Letters, 2009, 94(22): 221109.

DOI：10.1063/1.3148812

• gallium compounds
• III-V semiconductors
• photodetectors
• p-i-n photodiodes
• wide band gap semiconductors

We report low-noise GaN visible-blind homojunction p-i-n photodiodes. The devices are grown on a freestanding bulk GaN substrate and are fabricated using a "ledged" surface depletion technique to suppress the mesa sidewall leakage. For an 80-mu m-diameter photodetector, the dark current density is lower than 40 pA/cm(2). A room-temperature noise equivalent power of 4.27x10(-17) W Hz(-0.5) and a detectivity of 1.66x10(14) cm Hz(0.5) W(-1) are achieved at a reverse bias of 20 V. The noise performance of the reverse-biased GaN p-i-n photodiodes are among the best values reported to date and demonstrate the potential of GaN photodiodes for low-noise high-speed UV detection.

• 出版日期2009-6-1