Barrier height and surface states at cleaned InSb(110) surfaces

Abstract

The electronic properties of p-InSb(110) surfaces which were cleaned by the ion bombardment annealing technique are investigated by measurements of the integral and differential field effects. The field-induced changes in surface conductivity imply inversion layers with electron conduction in the space charge layer. The analysis of the experimental results yields the barrier height at the surface and the term spectrum of surface states. The general shape of the surface state density per energy interval shows a disorder-dependent continuous distribution with a minimum about midgap and increasing tails towards the bulk band edges. Near the conduction band minimum a peaking distribution of donor-type surface states is superimposed on the continuous distribution depending on the ion bombardment annealing conditions. The nature of the spectrum of surface states is discussed on the basis of intrinsic and extrinsic states.