CdSe nanowires grown by using chemical bath deposition

The Cadmium-selenide (CdSe) nanowire thin films were prepared on glass substrates by using chemical bath deposition (CBD) at 70 °C. Cadmium sulfate and sodium selenosulphate were used as Cd²⁺ and Se^2‑ ion sources, respectively. The CdSe nanowire film was annealed in an air atmosphere at 573 K for 1 hour. X-ray diffraction (XRD) results showed that the nanowire films as-deposited and annealed had mixed cubic and hexagonal phase. Scanning electron microscopy (SEM) indicated that the CdSe nanowires had lengths ranging from 642 nm to 2.5 μm and diameters ranging from 46 nm to 211 nm. The optical properties of the as-deposited and the annealed nanowire films, an investigated by recording the transmission spectra by using an UV-visible spectrophotometer revealed that the energy band gap decreased (from 1.78 eV to 1.50 eV) upon annealing. The conductivity measurements made by using four-probe methods for both the annealed and the as-deposited films showed that the resistivity, conductivity and activation energy changed upon annealing.