The application of asymmetric Schottky barrier and electrode area in an MgZnO metal-semiconductor-metal (MSM) solar-blind ultraviolet photodetector has been investigated by a physical-based numerical model in which the electron mobility is obtained by an ensemble Monte Carlo simulation combined with first principle calculations using the density functional theory. Compared with the experimental data of symmetric and asymmetric MSM structures based on ZnO substrate, the validity of this model is verified. The asymmetric Schottky barrier and electrode area devices exhibit reductions of 20 times and 1.3 times on dark current, respectively, without apparent photocurrent scarification. The plots of photo-to-dark current ratio (PDR) indicate that the asymmetric MgZnO MSM structure has better dark current characteristic than that of the symmetric one.
© 2014 Optical Society of America
Original Manuscript: September 18, 2013
Revised Manuscript: December 6, 2013
Manuscript Accepted: December 12, 2013
Published: January 15, 2014
Ping Wang, Qinghong Zheng, Qing Tang, Yintang Yang, Lixin Guo, Feng Huang, Zhenjie Song, and Zhiyong Zhang, "Dark current suppression of MgZnO metal-semiconductor-metal solar-blind ultraviolet photodetector by asymmetric electrode structures," Opt. Lett. 39, 375-378 (2014)