The piezoelectric photoacoustic (PPA) signals for Cu-rich CuGaSe2 (CGS) /GaAs (001) epitaxial layer (Cu/Ga = 1.09-2.16) grown by molecular beam epitaxy (MBE) were successfully obtained at liquid-nitrogen temperature. The bandgap energies of CGS (A-band) decreased and GaAs was not almost changed with increasing the Cu/Ga ratios. This phenomenon was very similar to that of free exciton (FE) by photoluminescence (PL) and the lattice parameter c by X-ray diffraction (XRD) measurements.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films