FORMATION OF Cu2SnS3 AND Cu2SnSe3 THIN FILMS

Abstract

Objective. The study shows the possibility of Cu2SnS3 and Cu2SnSe3 synthesis on glass substrates by annealing a Cu2Sn thin metal fi lm in chalcogen vapours in a vacuum graphite chamber of the quasi-closed volume type. Methods and methodology. The initial metal fi lms were deposited by thermal sputtering of a Cu2Sn alloy. It was shown by X-ray microanalysis that the elemental composition of the fi lms corresponds to the stoichiometry of the Cu2SnS3 and Cu2SnSe3 compounds. By X-ray diffraction, it was found that the obtained chalcogenide fi lms have a sphalerite-like crystal structure. Results. Diffractograms of Cu2SnS3 and Cu2SnSe3 chalcogenide fi lms contain peaks characteristic of the cubic symmetry group F-43m. These peaks correspond to refl ection planes (111), (220), and (311). Lattice constants for Cu2SnS3 and Cu2SnSe3 are 5.38 Е and 5.67 Е respectively. The activation energies of direct-gap transitions were determined by the method of IR-spectroscopy: Ea = 0.96 eV for Cu2SnS3 and Ea = 0.70 eV for Cu2SnSe3. The absorption coeffi cients for the Cu2SnS3 fi lm is 2·105 cm–1, and for the Cu2SnSe3 fi lm is 1·105 cm–1. Conclusion. Similar values of lattice parameters of synthesized fi lms and lattice parameters of ZnS and ZnSe crystals can contribute to the formation of functional elements of photoelectronics based on p-Cu2SnS3/n-ZnS and p-Cu2SnSe3/n-ZnSe heterojunctions

Keywords

• metal chalcogenides
• Cu2SnS3
• Cu2SnSe3
• quasi-closed volume.