The electronic structures of such compounds were calculated, using first-principles methods, for various vacancy-ordered structures: defect chalcopyrite, defect stannite and pseudo-cubic. It was shown that the valence-band top was made up of dangling bonds of anion atoms around vacancies and that the energy position hardly depended upon the vacancy ordering. However, the anti-bonding states of cation atoms and the cation-site vacancy acted as a potential barrier for electrons, and the band-gap energy depended sensitively upon the vacancy ordering.

Vacancy Ordering/Disordering and Electronic Structures of II1III2VI4 Compounds. M.Ishikawa, T.Nakayama: Journal of Crystal Growth, 2000, 214-215, 452-6