A low-temperature scanning tunneling microscopy study on the Sn- and Zn-doped InP(110) surfaces

A low-temperature scanning tunneling microscope has been used to study the (1 1 0)-cleavage surface of indium. phosphide (InP) at 4.2 K. InP is a III- V compound semiconductor, and we studied the behavior of doping atoms at di fferent bias voltages in both n- and p-type InP. In neither the n- nor the p-type InP did we observe Friedel oscillations, but the p-type InP with a Z n-dopant concentration of 2.7 x 10(18) cm(-3) showed an interesting behavio r at positive sample voltages: upon moving the tip Fermi level to the botto m of the conduction band, we observed that depressions in the surface topog raphy caused by the influence of the Zn doping atoms changed into elevation s with a triangular shape, This has previously been observed on p-type GaAs (1 1 0), and an explanation for these triangular features is not yet availa ble. (C) 2001 Elsevier Science B.V. All rights reserved.