Nanostructured CdS thin films deposited by spray pyrolysis method

Abstract

Influence of solution pH on the structural and optical properties of CdS films deposited by conventional spray pyrolysis technique was studied. X‐Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Photoluminescence spectroscopy (PLS), and Spectroscopic Ellipsometry (SE) methods were used for the characterization of the deposited films. PL spectrum of the film deposited from the solution with pH = 10.2 shows broad‐band PL emission located at 460 nm (2.7 eV), which can be attributed to the quantum size effect at grain sizes of <10 nm. No shifts of ϵ1 and ϵ2 due to the quantum size effect are observed in dielectric function spectra, what can be caused by low concentration of nano‐sized (<10 nm) CdS grains. The change in the film properties with the pH of the solution was analyzed in terms of variation of grain sizes of the polycrystalline films.