High sensitivity and fast response self-powered solar-blind ultraviolet photodetector with a beta-Ga2O3/spiro-MeOTAD p-n heterojunction

Solar-blind ultraviolet (UV) photodetectors are greatly desired in a number of areas in terms of military and civilian purposes, especially self-powered devices driven by the photovoltaic effect. Herein, a solar blind photodetector has been successfully achieved on a spiro-MeOTAD/beta-Ga2O3 organic-inorganic hybrid construction. The fabricated photodetector can operate with a self-powered mode and shows an obvious photodetection with a narrow spectrum region, exhibiting a high responsivity (65 mA W-1) and a large external quantum efficiency (32%) under low power intensity (similar to 1 mu W cm(-2)) UV illumination, at zero bias. Fortunately, the device shows a fast temporal pulse response (tau(rise) similar to 2.98 mu s and tau(decay) similar to 28.49 mu s), which is superior to the previously reported Ga2O3 based self-powered photodetectors. More importantly, the photodetector can operate stably and shows good repeatability. These excellent performances of the device could be attributed to the pre-existing band alignment of the Ga2O3 and spiro-MeOTAD, and are comparable to and/or even higher than those of other self-powered solar-blind UV photodetectors, which indicates that a device configuration based on a Ga2O3/spiro-MeOTAD heterojunction is certified as an excellent candidate for a high sensitivity, ultrafast response and self-powered photo-detecting device for solar-blind UV signals.