A New Approach in Chemical Bath Deposition of Cadmium Selenium Thin Films

This study aims to produce cadmium selenium (CdSe) thin films with a hexagonal structure using the chemical bath deposition (CBD) method. In this study, 0.075 g of cadmium chloride (CdCl2) is used as a Cd source, 0.06 g of etilendiamin tetra acetic acid [(EDTA), (C10H16N2O8)] as a complexing agent, and 0.1 g of selenourea [CSe(NH2)(2)] as a selenium source. Ammonia (NH3) is employed to adjust the pH value of the solutions and varying amounts of Na2SO3 (from 0.1 to 1.6 g) are used as a reducing agent. This chemical combination has been used for the first time to produce CdSe thin films. X-ray diffraction (XRD) results confirm that CdSe thin films exhibit a hexagonal structure without requiring annealing. The energy band gap values calculated via absorption graphs range from 1.76 to 1.91 eV. The surface morphologies are examined using scanning electron microscope (SEM) images. SEM images show that there are no voids, cracks, or pinholes. The software named ImageJ is used to determine surface roughness, showing range from 6 to 8 nm. The photographs of the samples show that some films adhere homogeneously to the surfaces of substrates, depending on the amount of Na2SO3 used.