摘要： The characteristics of a novel 0D/3D heterojunction photodetector fabricated using solution processed colloidal MoS2 quantum dots (QDs) on GaAs is being presented. MoS2 QDs with a dimension of ~2 nm, synthesized by standard sono-chemical exfoliation process of 2D layers have been used for the purpose. The microscopic and spectroscopic studies confirmed the formation of semiconducting (2H phase) MoS2 QDs. The photodetectors were fabricated using n-GaAs substrates with two different doping concentrations resulting in n-n heterojunctions between n-type 0D MoS2 QDs and bulk n-GaAs. The devices fabricated using GaAs having higher doping concentration, upon illumination, showed an increase of reverse current of the order of ~102, while the same with lower doping concentration showed an increase of the order of ~103. All the heterojunction photodetector devices show a broadband operation over the visible wavelength range of 400 – 950 nm, with a peak responsivity of the devices being observed at 500 nm. The peak responsivity and detectivity are found to be ~400 mA/W and ~4 × 1012 Jones, respectively even without any external applied bias, which are useful for self-powered photodetection. Results indicate that colloidal MoS2/GaAs based hybrid heterostructures provide a platform for fabricating broadband photodetectors by using highly absorbing MoS2 QDs, which may show the pathway towards next-generation optoelectronic devices with superior detection properties.