Electrically pumped random lasing with an onset voltage of sub-3 V from ZnO-based light-emitting devices featuring nanometer-thick MoO3 interlayers

Abstract

We have previously reported on electrically pumped random lasing (RL) with onset voltages at least 3.3 V from ZnO-based light-emitting devices with metal–insulator–semiconductor (MIS) structures in the form of Au/SiO₂/ZnO. Here, by inserting an ∼5 nm thick MoO₃ layer between SiO₂ and ZnO films in the aforementioned MIS structured device, the RL onset voltage is decreased to only ∼2.6 V and, moreover, the output optical power is multiplied several times. Such improved RL performance is ascribed to the enhanced injection of holes into ZnO via the MoO₃ interlayer that features a low-lying conductive band and therefore a large work function.