Vacuum Violet Photo-Response of AlGaN-Based Metal-Semiconductor-Metal Photodetectors
ZHOU Dong1, LU Hai1**, CHEN Dun-Jun1, REN Fang-Fang1, ZHANG Rong1, ZHENG You-Dou1, LI Liang2
1Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 2National Key Laboratory of Monolithic Circuits and Modules, Nanjing Electron Devices Institute, Nanjing 210016
Abstract：Al0.5Ga0.5N-based metal-semiconductor-metal photodetectors (PDs) with a large device area of 5×5 mm2 are fabricated on a sapphire substrate, which are tested for vacuum ultraviolet light detection by using a synchrotron radiation source. The PD exhibits low dark current of less than 1 pA under 30 V bias and a spectral cutoff around 260 nm, corresponding to the energy bandgap of Al0.5Ga0.5N. A peak photo-responsivity of 14.68 mA/W at 250 nm with a rejection ratio (250/360 nm) of more than four orders of magnitude is obtained under 30 V bias. For wavelength less than 170 nm, the photoresponsivity of the PD is found to increase as wavelength decreases, which is likely caused by the enhanced photoemission effect.
2013, Vol. 30 
