P-type β-Ga2O3 metal-semiconductor-metal solar-blind photodetectors with extremely high responsivity and gain-bandwidth product

P-type beta-Ga2O3 films deep-ultraviolet (DUV) solar-blind metal-semiconductor-metal (MSM) photodetectors (PDs) are fabricated with extremely high photoresponsivity (9.5 x 10(3) A/W), external quantum efficiency (4.7 x 10(6)%), detectivity (1.5 x 10(15) Jones), and gain-bandwidth product (10(6)) at 5 V bias, very low noise equivalent power (4.9 x 10(-16) W/Hz(1/2)) and high specific detectivity (1.9 x 10(13) Jones) at 1 kHz and 3 V bias. The excellent performances of the p-type beta-Ga2O3 DUV MSM PDs are attributed to the charge carrier multiplication via collective excitation of aggregated excitons and/or electron-hole liquid within the fabricated high-quality p-type beta-Ga2O3 films, which possess the room-temperature Hall resistivity of 52.6 Ucm, the hole mobility of 41.4 cm(2)/V,s, and the hole concentration of 2.86 x 10(15) cm(-3). The unprecedentedly high photoresponsivity and detectivity and the carrier multiplication mechanism in high-quality p-type beta-Ga2O3 films pave a novel way to fabricate super sensitive DUV PDs based on p-type wide-bandgap oxide semiconductors. (C) 2020 Elsevier Ltd. All rights reserved.