A combined study of electrically active defects in crystalline samples was carried out by using both scanning electron microscopy and scanning tunnelling microscopy. Charged structural and compositional defects were revealed by the remote electron beam-induced current mode of the scanning electron microscope. Electronic inhomogeneities of the samples were analyzed, to nm resolution, by means of current imaging tunnelling spectroscopic measurements. This revealed the existence of built-in electrostatic barriers, as well as local variations in the surface band-gap, in the defect areas which were imaged by the remote electron beam-induced current.

G.Panin, C.Díaz-Guerra, J.Piqueras: Applied Physics Letters, 1998, 72[17], 2129-31