Influence of Substrates on the Photoelectrochemical\nPerformances of Ag₂ZnSnSe₄ Thin Films

Abstract

This work describes\nthe photoelectrochemical (PEC) performance\nof Ag₂ZnSnSe₄ (AZTSe) thin films prepared on\nvarious conductive substrates such as Al, Cu, Ag, and conventional\nglass by a thermal evaporation method. The X-ray diffraction analysis\nconfirms that the deposited films are the pure tetragonal structure\nof AZTSe. The scanning electron microscope (SEM) images show polygonal-shaped\nand\nspherical-rich particles, which are uniformly distributed over the\nsubstrates and are densely packed. By comparing the SEM images, the\naverage particle size of Ag/AZTSe film seems to be higher than that\nof the other films. The energy-dispersive X-ray analysis is witnessed\nfor nearly stoichiometric values for the films. The optical absorption\ncoefficient of AZTSe thin films is found to be about 10⁴ cm^–1 and its band gap is found in the range of\n1.54–2.15 eV. The Mott–Schottky plot shows n-type conductivity\nfor all of the films. The <i>J</i>–<i>V</i> plot confirms the photoactivity for all of the films. Among the\nfilms, the Ag/AZTSe film shows higher power conversion efficiency\nof about 0.32%. However, further investigation is needed to optimize\nthe thickness of the conductive layer for improving the efficiency\nof photoelectrochemical cell in comparison to that of the industrially\nestablished materials.