Enhanced photoresponse of ZnO quantum dot-decorated MoS ₂ thin films

Transition metal dichalcogenides (TMDs) have been attracting attention because of their applications in optoelectronics and photo-detection. A widely used TMD semiconductor is molybdenum disulfide (MoS2), which has tremendous applications because of its tunable bandgap and high luminescence quantum efficiency. This paper reports on high photo responsivity (Rλ ∼ 1913 A W−1) of MoS2 photodetector by decorating a thin layer of zinc oxide (ZnO) quantum dots (ZnO-QDs) on MoS2. Results show that Rλ increases dramatically to 2267 A W−1 at Vbg = 30 V. The high response of ZnO-QDs/MoS2 heterostructures is attributed to a number of factors, such as effective charge transfer between ZnO-QDs and MoS2 surface and re-absorption of light photon resulting in production of electron–hole pairs.