Observation of two-photon-induced photoluminescence in ZnO microtubes

Abstract

The micrometer-sized ZnO tubes were fabricated by a hydrothermal method and characterized by scanning electron microscopy, high resolution transmission microscopy and micro-Raman spectroscopy. Photoluminescence (PL) emission from ZnO microtubes excited by light in the ultraviolet range from xenon lamp was measured. By using nanosecond laser beam at 527nm to excite ZnO microtube, we observed two-photon induced PL emission with an intense peak at 3.15eV and a weak peak at 2.65eV, which was confirmed by the quadratic dependence of the emission intensity on the excitation power.