Characterization of heteroepitaxial CuIn3Se5 and CuInSe2 layers on Si substrates

Abstract

Epitaxial CuIn3Se5 layers were grown on CuInSe2/Si(111) substrates by molecular beam epitaxy. Photoemission spectra of (112)-oriented CuIn3Se5 and CuInSe2 epitaxial layers were studied and the structures in the upper valence band are correlated with the Cu 3d and Se 4p density of states. The main valence band of CuInSe2 exhibits the three peak structure (consistent with theory) while a broadband with a shoulder is observed for the CuIn3Se5 phase. Electron channeling and x-ray diffraction confirmed the epitaxial growth of (112)-oriented layer. Surface and bulk composition analyses, position of valence band maxima, and a Se related vibrational mode at 153 cm−1 in Raman scattering measurements established the growth of the CuIn3Se5 phase.