SHARP OPTICAL-EMISSION FROM CUINSE2 THIN-FILMS GROWN BY MOLECULAR-BEAM EPITAXY

Optical properties Of CuInSe2 (CIS) films grown on (001) GaAs by molec ular beam epitaxy (MBE) have been investigated by means of low tempera ture photoluminescence (PL) spectroscopy. Distinct emission fines incl uding a bandedge emission were observed reproducibly from Cu-rich film s, indicating high crystalline quality. Such well-defined PL spectra h ave made possible the extensive characterization of radiative recombin ation processes through the intrinsic defects in this material; some o f the emission lines were attributed to phonon replicas with a phonon energy of 28-29 meV for the first time. PL spectra were found to be ve ry sensitive to the MBE growth parameters such as substrate temperatur e, suggesting dominant defects in CIS epitaxial films can be controlle d by varying the growth conditions.