Electrochemical growth of Cu–Zn sulfides

Abstract

The ElectroChemical Atomic Layer Deposition (ECALD) methodology was proposed as a new approach to synthesize thin films of ternary Cu–Zn sulfides, technologically relevant for photovoltaic semiconductors, characterized by low cost of raw materials and absence of toxicity. An electrochemical characterization of the film was carried out by stripping voltammetry in order to set up the most opportune conditions for depositing Zn. The anodic stripping voltammetry points to the formation of a mixed Cu–Zn sulfide in the film: this approach represents probably the first successful synthesis of a ternary Cu–Zn sulfide. The chemical composition of the films was determined through ICP-OES analysis, and a Cu/Zn ratio equal to about 6 was evidenced. The optical properties of the ECALD film were investigated through Diffuse Reflectance Spectroscopy. The experimental band gap value confirms the potential applications of these compounds for photovoltaic purposes.