Growth of Cu(In,Ga)Se2 thin films by a novel single flash thermal evaporation source

Abstract

A novel route of a single flash thermal evaporation technique has been used for deposition of Cu(In,Ga)Se2. This route allows the deposition of stoichiometric CIGS layers direct from powder elements without selenization or any treatment. Structure, optical properties and surface morphology of the deposited films at various substrate temperatures have been investigated using X-ray diffraction (XRD) analysis, Raman spectroscopy, photospectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy. The structure and the optical properties of deposited films depend on the substrate temperatures which play crucial rule on the stoichiometry of the film by changing mainly the content of selenium. Increasing the substrate temperature improved the crystallinity of the films and the best stoichiometric film has been found at 220°C, the grain size increased from 146 to 286 Å, Whereas, the band gap reduced to 1.37 eV.