Investigations on Hot-wall deposited Cadmium Sulphide buffer layer for thin film solar cell

Cadmium Sulphide (CdS) thin films were deposited on to well-cleaned soda lime glass substrates using hot wall deposition technique at room temperature. The structure of CdS thin films was found to be hexagonal with 〈0 0 2〉 orientation and after annealing the film crystallized to 〈0 0 2〉, 〈1 0 1〉, 〈1 0 2〉, 〈1 1 2〉 directions. Raman Spectroscopy confirmed the hexagonal structure with a shift at 312 cm−1. SAED pattern from the Transmission electron microscopy also confirmed the formation of hexagonal CdS. X-ray Photoelectron Spectroscopy confirmed the formation of CdS with relevant at% of Cd and S. Field emission scanning electron microscopy images revealed smooth surface of the thin film with distinctive grains. Atomic force microscopy results showed a surface roughness of 4.47 nm. Transmission spectra of the films were studied and the transparency was found to be above 80%. The optical band gap was found to be around 2.4 eV in accordance with the reported values. The results show that device quality buffer layers can be deposited using Hot-wall deposition.