Controllable synthesis of Ag2Se binary thin-film via electrochemical atomic layer epitaxy (ECALE) and its characterization

Herein, synthesis of Ag2Se nanofilms was attempted for the first time at room temperature using electrochemical atomic layer epitaxy (ECALE) in underpotential deposition (UPD) basis. Spectrochemical/electrochemical measurements verified a 2-D growth for the Ag–Se films when the deposition potentials were gradually adjusted to negative (−1 mV/cycle). Electrochemical impedance spectroscopy (EIS) measurements illustrated less interfacial charge transfer resistance at the nanofilm coated surface. Scanning electron microscopy (SEM) indicated that the film was composed of crystallites with size of around 110 nm. Energy dispersive X-ray spectroscopy (EDS) analyzes verified the 2:1 stoichiometric ratio for the compound and X-ray diffraction (XRD) analysis confirmed an orthorhombic β-Ag2Se crystalline phase. Ultraviolet–visible (UV–Vis) absorption measurements were performed to estimate the band gap of Ag2Se thin-film. Contact angle (CA) measurements demonstrated a decreased surface wettability. The proposed ECALE approach offered a low-cost and a facile method for the synthesis of epitaxial Ag2Se nanofilms that could be controlled at the atomic level.