Electrically pumped random lasing with an onset voltage of sub-3 V from ZnO-based light-emitting devices featuring nanometer-thick MoO₃interlayers

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.

Ultraviolet Stimulated Emission from Sol-Gel Spin Coated ZnO Thin Films

“…There are several mechanisms by which stimulated emission is generated in ZnO thin films. These mechanisms include random lasing [17][18][19], exciton-exciton P-band lasing [20,21], electron-hole plasma lasing or N-band lasing [22], nanosized or microsized whispering gallery mode dielectric resonators [23][24][25][26], coherent scattering of light by surface undulations [27], N-band lasing enhanced by top-down microdisc structuring [28], and coherent reflection from selfassembled ZnO hexagons [20].…”

Low-threshold voltage ultraviolet light-emitting diodes based on (Al,Ga)N metal–insulator–semiconductor structures

“…Although MIS-type near-ultraviolet and violet LEDs were demonstrated more than two decades ago, 3) most recent developments are focused on emitters synthesized from ZnObased materials. 1,[4][5][6] However, the electroluminescent intensities of devices based on these materials are relatively low, which is attributed to their poor crystalline quality. In comparison, III-nitride materials generally have better crystalline qualitydespite their unique doping and high Al incorporation challengesmaking them suitable for efficient MIStype emitters.…”