Effect of gas concentration on structural and optical characteristics of ZnO nanorods

ZnO nanorods have been synthesized using vapor–liquid–solid (VLS) growth technique under different flow ratios of Ar/O2. The effects of different gas concentrations on the crystal structure, surface morphology, and optical properties of ZnO nanorods are investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL), and Raman spectra measurements. The PL measurements exhibit two peaks, one around 383 nm and the other around 502 nm, which correspond to ultraviolet (UV) and green emission. With decrease in flow ratio of Ar/O2, the blue-shift of UV PL spectra is observed in the nanorods. In addition, a nanogenerator with ZnO nanorods is fabricated. The output current is generated in the device and showed the Schottky-like current–voltage characteristic.