Size Dependence of Gas Sensitivity of ZnO Nanorods

Abstract

We report the structure, optical, and gas-sensing properties of ZnO nanorods with different diameters. Vertically well-aligned homogeneous nanorods were grown along the c-axis orientation. The shift of Raman scattering E2 (high) mode and photoluminescence (PL) spectra were used to study the dependences of nanorod diameters on the stress and oxygen vacancy. Gas sensors were prepared and tested for the detection of C2H5OH and H2S (100 ppm) in air. It was found that the thin nanorods have a significantly better sensing performance than the thick nanorods. We provide a possible explanation from the aspect of the sensing mechanism of the surface reaction process.