Ternary AgInSe ₂ film electrode created using selenization of RF magnetron sputtered Ag-In metal precursor for photoelectrochemical applications

AgInSe ₂ ternary semiconductor thin films are deposited on glass substrates and indium-doped-tin-oxide (ITO)-coated glass substrates using the selenization of magnetron sputtered Ag-In metal precursors. X-ray diffraction (XRD) and energy-dispersive analysis of X-ray (EDAX) results show that the crystal phase of samples changed from AgInSe ₂ to a solid mixture of AgInSe ₂ and Ag ₂Se with a decrease in the [In]/[In + Ag] molar ratio in samples. The direct and indirect energy band gaps of the samples vary in the ranges of 1.27-1.45 eV and 0.91-1.17 eV, respectively, depending on the [In]/[In + Ag] molar ratio in samples. The flat-band potentials of samples are in the range of -0.47 to -0.71 V (vs. normal hydrogen electrode) in a solution containing Na ₂S (0.35 M) + K ₂SO ₃ (0.25 M) obtained using Mott-Schottky measurements. The maximum photocurrent density of the samples on ITO-coated glass substrates is 31.7 mA/cm ² at an external potential of +1.0 V (vs. Ag/AgCl) in the solution containing Na ₂S (0.35 M) + K ₂SO ₃ (0.25 M) ions. Highlights: AgInSe ₂ is deposited on substrates using selenization of Ag-In precursors. The direct energy band gaps of the samples were in the range of 1.27-1.45 eV. Sample with [In]/[Ag + In] ratio of 0.49 has a maximum PEC response.