Abstract
A single-heterostructure of CuGaSe2/CuAlSe2 chalcopyrite semiconductors was successfully grown epitaxially on a GaAs(001) substrate using a low-pressure metal organic chemical vapor deposition technique. The valence-band discontinuity for the CuGaSe2/CuAlSe2 heterointerface was estimated to be 0.8±0.1 eV by means of X-ray photoelectron spectroscopy. The CuGaSe2/CuAlSe2 structure was found to have the straddling-type heterointerface, and the band discontinuity was found to be distributed mainly in the valence band.