Structural, Morphology and Optical properties of Ag-doped Nanostructured CdS thin films

Abstract

Chemical Spray Pyrolysis (CSP) method is employed to deposit CdS and Silver (Ag)-doped CdS films. The effect of Ag doping at 1, and 3 wt-% levels is considered. The principal X-ray diffraction peak was along (020) plane. Maximum grain size was observed at the (CdS:3% Ag) films. The dislocation density parameter increased from 53.04 to 37.08, whereas the strain(%) parameter decreases from 25.23 to 21.10. Atomic force Microscope (AFM) images indicate a polycrystalline structure, and reveal that the undoped CdS and doped CdS:Ag films have discontinuous surfaces with spherically grains decreased from (58.05 to 45.77 nm) with the increase of doping from 0% to 3%. Root-mean square (R_rms) roughness of surface is about (9.81-5.42) nm. Also, there was a clear decrement in transmittance as Ag increment. The optical energy bandgap E_g has been decreased from 2.47 to 2.37 eV due to increase in Ag content. The absorption coefficients with photon energy increase with increasing concentration doping in Ag.