ZrO 2 quantum dots/graphene phototransistors for deep UV detection

Abstract ZrO 2 is a promising material for deep-UV detection application, yet the low carrier density and high crystal lattice defects hinder the device performance. Graphene is an attractive material for photoactive and charge transport layers in photodetectors, but the photoresponsivity have been limited by the weak light absorption, no wavelength selectivity. Here, we demonstrate heterostructure phototransistors consist of graphene as the conducting channel, which is covered by a film of ZrO 2 quantum dots as the light absorption layer. Light absorption in the quantum dots layer creates electron-hole pairs. Under the built-in electric field, the electrons are trapped in ZrO 2 acting as an additional light tunable gate, whereas the holes are transferred towards the graphene. The ZnO 2 /Graphene heterostructure, with a high photoresponsivity of 22 A W −1 and wavelength selectivity to deep UV wavelength range (220–250 nm) at low operating voltage, is promising to be integrated into solution processed and low-cost optoelectrical devices.