Cyclic Voltammetric and Chronoamperometric Deposition of CdS

Abstract

CdS was electrochemically deposited on ITO using cyclic voltammetry (CV) and chronoamperometry (CA) in aqueous solution. To fabricate the CdS thin films, a potential ranging from −0.3 to −1.2 V was applied for CV and a constant potential of −1.1 V was applied for CA (Ag|AgCl). The deposited CdS thin films were characterized in detail using XRD, AFM and SEM. UV/Vis-transmittance was used to determine the band-gap energy (E_g) of the films. The dopant densities and flat band-potentials (E_fb) were determined using Mott-Schottky plots. The CdS film obtained by CV deposition was observed to be rougher and sparser than that obtained by CA deposition. This was attributed to the alternating reduction–oxidation, corresponding to deposition–dissolution of CdS. The carrier density of the CdS film deposited by CV was measured to be as much as 17%.