CUALSE2 THIN-FILMS OBTAINED BY CHALCOGENIZATION

CuAlSe2 thin films have been synthesized by chalcogenization of thin C u and Al layers sequentially deposited by evaporation under vacuum. It is shown that CuAlSe2 films are obtained with some Cu2-deltaSe and Se phases present at the surface. These surface phases are suppressed by annealing under vacuum and by chemical etching in a KCN solution. At the end of the process, the XRD spectrum demonstrates that textured Cu AlSe2 films have been obtained with preferential orientation of the cr ystallites along the (112) direction. The gap of the films is 2.7 eV a s expected. The films are nearly stoichiometric, but their surface is quite rough. The XPS spectra show that some Na diffuses from the subst rate toward the surface during the annealing process. However, this Na is etched by KCN.