Abstract

Five sets of β-Ga2O3 films were prepared on sapphire substrates by RF magnetron sputtering at different sputtering powers (from 40W to 120W) and then annealed under 800°C in O2 atmosphere for 1h. Metal-semiconductor-metal structured photodetectors (PDs) with coplanar interdigital electrodes on these β-Ga2O3 films were fabricated to evaluate the solar-blind photo detection performance. The phase structure, growth morphology, photoluminescence (PL) spectra and the solar-blind detection performance of the films was investigated by XRD, AFM, photoluminescence spectrometer, and Keithley 4200 system. The results show that the obtained gallium oxide films are crystallized in β phase, all of which have (-201) crystal orientation. The sputtering power increases, the grain size becomes larger, and the crystalline quality of the film obtained under 100W sputtering power is the best. The PL spectra of all films showed wide-range UV-blue-green luminescence peaks from 350 nm to 600 nm, among which the resulting film at 100W had the highest level of dark blue luminescence (457 nm). The solar-blind UV PDs prepared based on the β-Ga2O3 thin films obtained at 100 W power showed relatively excellent photoelectric detection performance, with dark current as low as 1.08pA, a wavelength of 254nm, an optical power density of 1000μw/cm2, and 15V bias voltage of 2.6×103. The optical responsivity, detection efficiency, and external quantum efficiency of the device are 6.92×10^-2 mA/W, 1.05×10¹¹ Jones, and 0.034%, respectively. This excellent performance is related to the better crystallization quality and higher dark blue luminescence level of the film at 100W power.

Biography

Min Zhang received the B.S. degree in materials forming from Northeastern University and the Ph.D. degree in material physics and chemistry from Dalian University of Technology, Dalian, China, in 2004 and 2008, respectively. From 2008 to 2009, he was a Postdoctoral Fellow in the National Core Research Center for hybrid materials, Pusan National University, South Korea. In 2009, he joined the School of Physics and Electronic Technology, Liaoning Normal University. From 2016 to 2017, he was a visiting scholar in the Department of Materials Science and Engineering at Rensselaer Polytechnic Institute, Troy, USA. He is currently a Professor with the School of Physics and Electronic Technology, Liaoning Normal University. His research interests include ultra-wide bandgap semiconductor film and devices for solar-blind UV photo-detection, functional films and hard coatings, etc. He is a Guest Editor for the journal Coatings, and He has published over 60 peer-reviewed papers and delivered invited talks at major international conferences. He has led over 6 research projects, including national research projects and provincial and ministerial-level projects.