A hybrid MoS2 nanosheet–CdSe nanocrystal phototransistor with a fast photoresponse

Abstract

2-Dimensional (2D) and 0-dimensional (0D) hybrid nanostructures have been reported as promising new systems for highly-sensitive and wavelength-tunable photodetectors. Although the performance of hybrid photodetectors was enhanced by charge injection from 0D nanocrystals (NCs) to 2D nanosheets (NSs), the response time of hybrid photodetectors is still very slow due to the trapping and leakage of residual carriers at the interfaces of the hybrid materials. Here, we demonstrate a MoS₂/CdSe hybrid phototransistor with enhanced responsivity of 2.5 × 10⁵ A W⁻¹ and detectivity of 1.24 × 10¹⁴ Jones. In addition, the device exhibited a fast rise (τ_rise) and decay time (τ_decay) of 60 ms, respectively. The mechanism for the improved photoresponse time has been discussed using a charge injection model in an n–n type heterojunction energy band diagram of hybrid materials.