CHARACTER OF SURFACE-STATES AT INSB SURFACES

The structural and electronic properties of real (oxidized) and of clean InSb (110) surfaces are investigated by RHEED and by measurements of integral field effect and of differenlial field effect. The procedure of sample preparation and of surface treatment allows to study the influence of surface structure and of surface defects on (lie surface properties. The RHEED patterns show dependent on surface conditions different streak/spot systems indicating the existence of various compounds in the surface region. The electric measurements provide term spectra of the surface states consisting of continuous distribution with a minimum near the middle of the energy gap as well as increasing tails towards the band edges and within the energy bands. Depending on the surface condition fine structures are superposed to the continuous distribution. The results are understood by intrinsic and extrinsic states which are discriminated by their different response to chemical and physical influences. © 1979.