Current imaging of cleaved silicon pn junctions with an ultrahigh vacuum scanning tunneling microscope

Abstract
Current imaging of cleaved two‐dimensional silicon pn junctions with an ultrahigh vacuum scanning tunneling microscope is presented. In order to be able to distinguish between p‐type material, n‐type material, and the depletion region a voltage ramp is applied to the p side of the junction, while the voltage on the n side is constant. At the same time standard topography and stabilization current plots give no indication of the presence of the pn junctions. The IV characteristics measured over different parts of the junctions are explained. The influence of the shape of the cleaved surface on the measurements is discussed.