Structural and Optical Properties of Nanocrystalline CdO Thin Film Growth by Solid-Vapor Deposition

Abstract

Nanocrystalline cadmium oxide (CdO) thin film was successfully synthesized by a vapor transport process (solid-vapor deposition) without catalyst. Cadmium powder was heated to 1235 K in a tube furnace, and the resultant vapor was carried to the silicon substrate zone by a flow argon gas with oxygen. Scanning electron microscopy revealed that the product was of nanocrystalline cadmium oxide. X-ray diffraction and energy dispersive X-ray techniques were used to characterize structural properties. The grown nanocrystalline thin film had a grain size of 35 nm. Photoluminescence spectroscopy was conducted to investigate the optical properties of the CdO. The red-shift direct band gap energy of the nanocrystalline CdO was at 511 nm (2.43 eV), whereas that of CdO bulk was at 491 nm (2.5 eV).