Ultraviolet lasing and time-resolved photoluminescence of well-aligned ZnO nanorod arrays

Abstract

Well-aligned ZnO nanorod arrays were synthesized by thermal evaporation of ZnO powder on ZnO thin films. The nanorods are almost the same length of 5.5μm and well-oriented perpendicular to the substrates. The time-integrated and time-resolved photoluminescence spectra of the nanorod arrays revealed the existence of laser action with the excitation threshold of 130μJ∕cm2 and emission lifetime of less than 30 ps. At the excitation fluence a little below threshold, the decay fits well to a biexponential function with a fast component (∼80ps) and a slower component (∼360ps).