Hydrothermal fabrication of well-ordered ZnO nanowire arrays on Zn foil: room temperature ultraviolet nanolasers

Hydrothermal fabrication of well-ordered ZnO nanowire arrays on Zn foil: room temperature ultraviolet nanolasers–September 2011

JY Kim, H Jeong, and DJ Jang… – Journal of Nanoparticle Research
Well-ordered nanowires of the hexagonal wurtzite ZnO having an average diameter of 80 nm, a typical length of 12 μm, and a mean packing density of 7.5 nanowires μm−2 have been directly grown on Zn foil in a preferred [0001] direction by a hydrothermal process and employed for room temperature ultraviolet nanolasers. The lasing action of arrayed ZnO nanowires has been observed from 370 to 400 nm with threshold irradiance of 25 kW cm−2. Photoluminescence decays biexponentially: the fast component is attributed to free-exciton decay, and the slow one is to bound-exciton decay. The amplitude of the fast component increases whereas its lifetime decreases with the increment of threshold irradiance, suggesting that ZnO nanowire arrays undergo a change in the lasing mechanism from exciton–exciton scattering to electron–hole plasma recombination. … Absorption spectra were measured using a StellarNet EPP2000C UV–VIS reflectance spectrometer, and Raman spectra were measured using an OLYMPUS BX41 confocal microscope Raman system equipped with a Dynamic Laser LS300 Ar laser as the excitation source.