Ultraviolet random lasing from Mg0.12Zn0.88O:N/ZnO:Ga single-heterostructure diode

A heterostructure device consisting of nitrogendoped Mg0.12Zn0.88O and gallium-doped ZnO thin films was grown on c-plane sapphire substrate using RF plasmaassisted molecular beam epitaxy. Current–voltage and photocurrent characteristics indicate the formation of a p–n junction. Random lasing behavior with lasing modes centered at 356 nm was observed. A low-threshold current of 6 mA was determined, and an output power of 34 nW was measured at an injection current of 8 mA. The film contains columnar structures with much air gaps, which assist in light scattering to achieve necessary gain for random lasing.