PREPARATION AND PROPERTIES OF SINGLE-CRYSTAL CUALSE2 FILM

Epitaxial CuAlSe2 film has been grown on the GaP(100) substrate by molecular beam epitaxy, and its optical and electrical properties have been characterized. The spectrum of optical reflectance suggests that the band gap of the film is about 2.7 eV, which agrees with that of the bulk material. The photoluminescence spectrum at 77 K showed no band edge emission, but only deep level-related emissions ranging from 520 nm to 870 nm. The CuAlSe2 sample exhibits n-type conductivity with the resistivity of 0.02 OMEGA.cm, the carrier concentration of 4 x 10(18) cm-3 and the mobility of 60 cm2.V-1.s-1.