Underpotential co-deposition of ternary Cu-Te-Se semiconductor nanofilm on both flexible and rigid substrates

Abstract

To achieve homogeneous ternary compounds, the growth rates of the component species in a solution must be equal and the processes must be simultaneous. The conditions necessary for the growth of one species should not prevent the growth of the others. Herein we present a synthesis of Cu3Te2Se2 semiconductor nanofilms on indium tin oxide (ITO)-coated polyethylene terephthalate (ITO-PET), ITO-coated glass, and Au plate substrates by an electrochemical underpotential co-deposition (UPCD) method from the same solution at a constant potential. The chemical, morphological, and optical properties of the synthesized nanofilms were determined by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, ultraviolet–visible absorption spectroscopy (UV/Vis), and current-voltage (I-V) studies. The chemical formula of the deposited nanofilms was confirmed as Cu3Te2Se2 by X-ray photoelectron spectroscopy. The SEM images exhibited uniform nano-scale (∼40 nm) distribution of the Cu3Te2Se2 nanofilms. The band gaps of the deposited films were determined according to the different deposition times and potentials. The XRD results showed crystalline and single-phase forms of Cu3Te2Se2 nanofilm. Finally, the I-V curves of the Cu3Te2Se2/ITO heterojunctions at room temperature (RT) under normal light conditions indicated matched those of a diode model.