EBIC contrast of defects in cadmium telluride. I. Experiments

Abstract

Abstract Electron-beam-induced current (EBIC) contrast of freshly introduced dislocations and as-grown defects have been investigated in n-type CdTe (n ∼ 1015–1016cm–3). The carriers were collected by a Schottky diode perpendicular to the electron beam. The width of the space-charge region (SCR) of the diode was of the same order of magnitude as the penetration depth of the electrons of the scanning electron microscope. The contrast c was recorded as a function of the accelerating voltage E 0 (5–30 kV in 5kV steps). Variable recombination at dislocations in the SCR is evident from the observations. The EBIC contrast of dislocations perpendicular to the surface exhibits two kinds of behaviour with E 0, which are interpreted in terms of recombination in both the SCR and the bulk region of the diode. In the configuration studied, dislocations perpendicular to the surface and ‘point-like’ defects can produce not only similar EBIC images—circular dark spots—but also similar c = f(E 0) curves.