A low-temperature scanning tunneling microscope has been used to study the (110)-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 different 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 Zn-dopant concentration of 2.7×10 18 cm −3 showed an interesting behavior at positive sample voltages: upon moving the tip Fermi level to the bottom of the conduction band, we observed that depressions in the surface topography caused by the influence of the Zn doping atoms changed into elevations with a triangular shape. This has previously been observed on p-type GaAs(110), and an explanation for these triangular features is not yet available.