Field effect measurements on the A and B {111} surfaces of indium antimonide

Abstract

Large signal alternating current field effect experiments have been performed at 113° K on the A and B {111} “real” surfaces of InSb exposed to different ambients. Discrete fast surface states were observed in the energy gap near the valence as well as near the conduction band edge on both types of surfaces. The discrete state near the conduction band edge exhibited essentially the same density on the A and B surfaces, while the state near the valence band edge was found to be more dense on the B surface. In all cases, both surfaces were p-type, the B surface being invariably more p-type than the A surface. A model is presented according to which the surface state near the conduction band edge is acceptor-like and characteristic of the In atom while the surface state near the valence band edge is also acceptor-like but characteristic of the Sb atom. This model is consistent with the Gatos-Lavine model of the polar surfaces of the III-V compounds.