Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics

Abstract

Integration of graphene with semiconducting quantum dots (QDs) provides an elegant way to access the intrinsic properties of graphene and optical properties of QDs in a single hand to realize the high-performance optoelectronic devices. In the present study, high-performance photodetector based on graphene: CdSe QDs/CdS nanorod heterostructures, are demonstrated. The resulting heterojunction photodetector with device configuration ITO/graphene: CdSe/CdS nanorods/Ag show excellent operating characteristics including a maximum photoresponsivity of 15.95 AW -1 and specific detectivity of 6.85×10 12 Jones measured at 530 nm. The device exhibits a photoresponse rise time of 545 ms and a decay time of 539 ms. Furthermore, the effect of graphene nanosheets on the performance enhancement of heterojunction photodetector was explored. The results indicate that, due to the enhanced energy transfer from photoexcited QDs to graphene layer, light absorption is increased and excitons are generated. Also, the graphene: CdSe QDs/CdS nanorod interface can facilitate charge carrier transport effectively. This work provides a promising approach to develop high-performance visible-light photodetectors and utilization of advantageous features of graphene in optoelectronic devices.