Vacancy ordering was observed directly by means of high-resolution transmission electron microscopy of the interface of GaSe/GaAs(100) which had been grown by using molecular beam epitaxy. A Ga2Se3 crystalline film formed on the GaAs(100) substrate and acted as an intermediate layer, with a thickness of 1.6 to 3.2nm, between the film and the substrate. The vacancy ordering in Ga2Se3 was investigated by combining fast Fourier-transform analysis and simulations of high-resolution transmission electron microscopic images and diffraction patterns. The vacancies were preferentially distributed on the (100) crystal planes of the α-phase zincblende-structured selenide; a vacancy sheet appeared on the plane of each third separate Ga sheet.

Vacancy ordering of Ga2Se3 at GaSe/GaAs(100) interface Z.R.Dai, F.S.Ohuchi: Applied Physics Letters, 1998, 73[7], 966-8