Compositional dependence of Raman scattering and photoluminescence emission in Cu-Ga-Se films grown by MOCVD

摘要

This paper presents Raman scattering and photoluminescence (PL) analysis of polycrystalline Cu-Ga-Se films grown epitaxially on the GaAs substrate. In the compositional dependence of the Raman spectra of the CuGaSe2 films, the appearance of the ordered vacancy compounds (OVCS) CuGa3Se5 and CuGa5Se8 was observed. The dominating A, Raman modes were detected at 185, 166 and 159 cm(-1), respectively The PL bands of CuGaSe2, CuGa3Se5 and CuGa5Se8 at T = 10 K were detected at 1.615,1.72 and 1.76eV, respectively. The dominating PL emission channel is the band-to-tail (BT) type recombination.