Acceptor activation energies in epitaxial CuGaSe2 grown by MOVPE

Epitaxial CuGaSe2 layers were grown on GaAs 100 by MOVPE. Net carrier concentration and resistivity were examined with respect to temperature using a Van der Pauw geometry Hall setup. Net carrier concentrations from 2x1014cm 3 to 7x1016cm 3 were found with strong correlation to composition. All gallium rich samples show high compensation near 1. Thermal hole activation energies of 78 10meV and 106 10meV correspond to photoluminescence data from the same samples indicating two deep acceptors and one shallow donor. Mobilities up to 400cm2 Vs at room temperature and 1450cm2 Vs at 100K can be determined confirming high material quality.Measurement at lower temperatures was inhibited by carrier freeze out. We found mu prop T 3 2 indicating acoustic phonon scattering to be the dominant mechanism over the whole measureable temperature range