Investigation of nucleation and growth mechanism of selenium electrodeposited on ITO substrate

Abstract

The present paper reports an investigation of the electrodeposition mechanism of selenium (Se) thin films from an aqueous solution containing selenite ion (HSeO3−) (2 mM) and nitric acid on indium tin oxide (ITO) substrate, with pH 3.2 at room temperature, by using the cyclic voltammetry (CV) and chronoamperometry (CA) methods. The (CV) showed that the electrodeposition reaction is a quasi-reversible controlled by selenite ions diffusion. The (CA) indicated that the selenium particles are electrodeposited following the instantaneous three-dimensional (3D) nucleation model with a diffusion-controlled process, and the average diffusion coefficient (D) of selenite ions was determined to be 2.860 10−6 cm2 s−1. The X-rays diffraction (XRD) showed that the selenium has a hexagonal crystal structure. Scanning electron microscopy (SEM) indicated that the selenium is distributed with uniform nuclei. The UV–Visible spectrophotometry revealed that the optical band gap (Eg) for the electrodeposited selenium is found to be 1.62 eV.