Effect of cobalt on the photovoltaic properties of zinc selenide thin film deposited on fluorine-doped tin oxide (FTO) via electrochemical deposition technique

Abstract

This paper provides a detailed report on the effect of molar concentration on structural, optical and electrical properties of cobalt doped zinc selenide (ZnSe:Co) thin film. The molar concentration Co dopant was varied within 0%, 0.1%, 0.2% and 0.3%. ZnSe:Co was synthesized using the electrodeposition method. Different characterization techniques such as X-ray diffractometry, scanning electron microscope and four-point probe were used to study the optical, surface morphology and electrical properties of ZnSe:Co. The XRD analysis revealed that both Co-doped and undoped ZnSe are crystalline materials. The crystalline structure of ZnSe is cubic but changes to a face-centred cubic structure upon introduction of Co dopant. ZnSe:Co showed excellent absorbance, optical conductivity and refractive index. The energy bandgap was observed to decrease from 2.2 to 2.0 ​eV as the molar percentage increased from 0.1 to 0.3%. The conductivity of the cobalt doped Zinc selenide was observed to be 1.4244 ​× ​1011, 1.6655 ​× ​1011, 1.6655 ​× ​1011, and 2.4929 ​× ​1011 (S/m) for film grown with 0%, 0.1%, 0.2% and 0.3% Co dopant respectively.