Electroluminescence from ZnO nanorods with an n-ZnO/p-Si heterojunction structure

We report on the fabrication and electroluminescence of an n-ZnO nanorod/p-Si heterojunction. ZnO nanorods were grown on p-type Si substrates employing an easy low-temperature aqueous solution method. As-grown ZnO nanorods showed good crystallinity and a preferable c axial orientation. Electroluminescent devices were constructed using high-molecular-weight polymers as the fill-in, and the I-V characteristics were diode-like. A typical electroluminescent spectrum of such an n-ZnO/p-Si heterojunction under forward bias was composed of a narrow ultraviolet peak centred at 387 nm and a broad green band at 535 nm, consistent with the photoluminescent spectrum. The intensity of the ultraviolet light grew more quickly than that of the green light with the increasing of bias.