Wavelength modulated optical reflectivity spectra of CuAl1−XGaXSe2 crystals

Abstract

Exciton spectra of CuAl1 − XGaXSe2 solid solutions are investigated by wavelength modulated optical reflectivity at low temperatures (10 K). The energy position of n = 1 and 2 lines of the Γ4(A), Γ5(B) and Γ5(C) exciton series, as well as the Γ7(V1)–Γ6(C1), Γ6(V2)–Γ6(C1), Γ7(V3)–Γ6(C1) energy intervals, and the crystal field and spin–orbit splitting of the valence band are determined. The effective electron mass (mC1*) and hole masses (mV 1*, mV 2*, mV 3*) are estimated for CuAl1 − XGaXSe2 solid solutions as a function of the X value.