Multifunctional solar-blind ultraviolet photodetectors based on p-PCDTBT/n-Ga2O3 heterojunction with high photoresponse

Solar-blind ultraviolet (UV) photodetectors based on p-organic/n-Ga2O3 hybrid heterojunctions have attracted extensive attention recently. Herein, the multifunctional solar-blind photodetector based on p-type poly[N-9 '-heptadecanyl-2,7-carbazole-alt-5,5-(4 ',7 '-di-2-thienyl-2 ',1 ',3 '-benzothiadiazole)] (PCDTBT)/n-type amorphous Ga2O3 (a-Ga2O3) is fabricated and investigated, which can work in the phototransistor mode coupling with self-powered mode. With the introduction of PCDTBT, the dark current of such the a-Ga2O3-based photodetector is decreased to 0.48 pA. Meanwhile, the photoresponse parameters of the a-Ga2O3-based photodetector in the phototransistor mode to solar-blind UV light are further increased, that is, responsivity (R), photo-detectivity (D*), and external quantum efficiency (EQE) enhanced to 187 A W-1, 1.3 x 10(16) Jones and 9.1 x 10(4) % under the weak light intensity of 11 mu W cm(-)(2), respectively. Thanks to the formation of the built-in field in the p-PCDTBT/n-Ga2O3 type-II heterojunction, the PCDTBT/Ga2O3 multifunctional photodetector shows self-powered behavior. The responsivity of p-PCDTBT/n-Ga2O3 multifunctional photodetector is 57.5 mA W-1 at zero bias. Such multifunctional p-n hybrid heterojunction-based photodetectors set the stage for realizing high-performance amorphous Ga2O3 heterojunction-based photodetectors.

Automated summary

Solar-blind photodetectors based on p-organic/n-Ga2O3 hybrid heterojunctions have been investigated. A multifunctional photodetector based on p-PCDTBT/n-Ga2O3 is fabricated and shown to work in both phototransistor mode and self-powered mode. The introduction of PCDTBT reduces the dark current and enhances the photoresponse parameters of the photodetector to solar-blind UV light. Moreover, the built-in field in the heterojunction enables self-powered behavior.