Toward smart flexible self-powered near-UV photodetector of amorphous Ga2O3 nanosheet

Recently, the thin amorphous Ga2O3 nanosheet attracts enormous interest in dielectric and passivation materials, but it is still lack of the study about its photodetection performance. In this work, the amorphous Ga2O3 nanosheet is peeled off from the Ga solid-melt surface. Its amorphous characteristic is verified by selected area electron diffraction and X-ray diffraction. Owing to the limited absorption ability and abundant defect states, the amorphous Ga2O3 nanosheet photodetector shows a low photocurrent and slow response time even at a bias voltage. For improving the photodetection performance, PbI2 nanosheet is selected to be grown on the surface of amorphous Ga2O3 nanosheet. Owing to the built-in electric field at the interface, the Ga2O3/PbI2 heterojunction photodetector can work at a bias voltage of 0 V, along with a larger photocurrent of 1.6 nA and faster response times of about 2 ms (rise time) and 3 ms (decay time). When configured into the flexible photodetector, it also displays excellent self-powered photoresponse characteristic and excellent mechanical flexibility. This work paves the way for the development of high-performance flexible optoelectronic devices.