Ultrasensitive photodetectors promoted by interfacial charge transfer from layered perovskites to chemical vapor deposition-grown MoS₂

Abstract

Heterostructures for charge-carrier manipulation have laid the foundation of modern optoelectronic devices, such as photovoltaics and photodetectors. High-performance heterostructure devices usually impose stringent requirements on the material quality to sustain efficient carrier transport and charge transfer, thus leading to sophisticated fabrication processes. Here, a simple yet efficient strategy is proposed to develop ultrasensitive photodetectors based on heterostructures of chemical vapor deposition-grown MoS2 and polycrystalline-layered perovskites. The layered perovskites possess pure crystallographic orientation with conductive edges in contact with MoS2 , which gives rise to efficient light absorption, exciton diffusion, and interfacial charge transfer. In dark state, the mismatch of work functions of two materials facilitates low dark currents by the depletion of electrons in MoS2 . Under light irradiation, efficient exciton diffusion and interfacial charge transfer are realized in the heterostructures with type-II band alignment, which produces drifting electrons in MoS2 and leaves trapped holes in layered perovskites. The photodetectors present suppress noises and boost photocurrents, yielding a champion device with a responsivity of 2.5 × 104 A W-1 , and a specific detectivity of 4.1 × 1014 Jones. The results demonstrate a scalable approach for the integration of high-performance devices with high tolerance to defects.