Zinc oxide thin-film random lasers on silicon substrate

The room-temperature lasing in mirrorless zinc oxide thin-film waveguides on (100) silicon substrate was demonstrated. Through the post-growth annealing of high-crystal-quality zinc oxide thin films, laser cavities, due to closed-loop optical scattering from the lateral facets of the irregular zinc oxide grains, were generated. The high-intensity UV lasing from the mirror-less ZnO thin-film waveguides on lattice-mismatched silicon substrate was observed. It was found that the linewidth and lasing wavelength of the zinc oxide random lasers under 355 nm optical excitation were less than 0.4 nm and 390 nm, respectively.