Ternary compound MgTiO3 combined with graphene for solar-blind deep ultraviolet photodetection

Abstract

Ternary materials have gained great popularity in the field of solar-blind ultraviolet (UV) photodetectors due to their diverse band gaps. Whereas, quality problems brought by lattice damage and phase separation appear frequently during preparation, which greatly limit the application of ternary solar-blind photoresponsive materials. MgTiO3 (MTO), a ceramic material, has extensive application in microwave capacitors and dielectric resonators but takes no place in the field of photodetectors. Faced with this situation, this study investigates the effect of annealing on the structure of MTO thin film, and fabricates a solar-blind UV detector through combining MTO with graphene, which expands the application of ternary compound MTO to the field of photodetectors. Under solar-blind UV illumination, this MTO-based detector exhibits excellent performance with an open circuit voltage as high as 1.7 V. At 0 V bias, the detector exhibits an ultrafast response speed with the rise and decay time as short as 30 ms and 25 ms, respectively. Besides, a responsivity up to 46.5 mA/W, an external quantum efficiency (EQE) up to 20.4%, and a specific detectivity (D*) up to 6.14 × 1011 Jones also prove the great performance this detector owns. All the results achieved in this work not only suggest the great potential of MTO in being applied to fabricating solar-blind UV detectors, but also provide some guidance for the development of photovoltaic detectors based on other ternary semiconductor materials.