Electrically pumped random laser from ZnO nanocolumn based on back-to-back Schottky structure

Electrically pumped random laser has been achieved in a Au/ZnO nanocolumn/Au structure, which is back-to-back Schottky barrier. The origin of the lasing is that the electron from the reverse-biased Au/ZnO Schottky contact recombines radiatively with the hole from the forward-biased Au/ZnO Schottky contact, then the generated light is amplified in the ZnO nanocolumn, ultimately random lasing is realized. The threshold of the lasing is about 2 A/cm2, which is among the lowest threshold current of ZnO random lasing. The lasing peaks are randomly distributed between 375 and 420 nm, whose full width at half maximum (FWHM) can reach as narrow as 2 nm. The results reported in this paper indicate that ZnO nanocolumn based on back to back Schottky sturcture is suitable for achieving random laser.