Low-threshold lasing action in an asymmetric double ZnO/ZnMgO quantum well structure

ZnO/Zn0.85Mg0.15O asymmetric double quantum well (ADQW) and multiple quantum well (MQW) were fabricated with plasma assisted molecular epitaxy on c-plane sapphire, with their optical properties and optical pumped lasing characteristics studied. Due to the good crystalline quality, the lasing threshold of the MQW is ∼20 kW cm−2. The widths of the narrow well (NW) and the wide well (WW) of the ADQW were chosen to fascinate rapid LO phonon assisted carrier tunneling from NW to WW, so as to enhance the exciton density at the WW. Very low lasing threshold of 6 kW cm−2 has been achieved.