Structural and Optical Properties of Electrodeposited CdS Thin Film

D. G. Diso1, M. A.Y. Hotoro1, T. S. Bichi1 and I. M. Dharmadasa2
1Department of Physics, Kano University of Science & Technology, Wudil, Kano-Nigeria.
2 Electronic Materials & Sensors Group, Materials & Engineering Research Institute
Sheffield Hallam University, Sheffield S1 1WB, United Kingdom.
E-mail: dgdiso@yahoo.co.uk,
ABSTRACT: Cadmium sulphide (CdS) thin films have been deposited on glass/conducting glass
substrates using low-cost two electrode aqueous electrodeposition (ED) method. The structural
and molecular structure of the resulting films has been characterized using X-ray diffraction
(XRD) and Raman spectroscopy. The XRD results indicates that both as deposited and heat
treated ED-CdS layers are polycrystalline and have a hexagonal crystal structure with
preferential orientation along the (101) direction, while Raman measurement confirmed the two
peaks at 303cm-1 and 608cm-1 corresponding to the first and second order longitudinal optical
phonons (1LO) and (2LO) respectively. X-ray photoelectron spectroscopy (XPS) studies have
been performed to detect the photoelectrons emitted from the sample surface and compare the
results obtained on electrodeposited CdS with the vacuum cleaved CdS. The XPS spectra
measurement identified two distinct Cd 3d peaks (i.e. 3d5/2 and 3d3/2) with their binding energies
at ~405 and ~412 eV respectively. The S 2p peak has a binding energy of ~162 eV. The results
indicate that the composition of CdS layers is 52.9:47.1.The bandgap of the heat treated films
gives 2.42 eV using optical absorption measurements which are close to the bulk CdS. The
results from the 3D-AFM measurement shows that the material tends to grow as columns (nanorods)
leaving spaces in between in some areas