Published in J. Vac. Sci. Technol. B 20, 1677 (2002).
Yang Dong (a), R. M. Feenstra (a), R. Hey (b) and K. H. Ploog (b)
(a) Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
(b) Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117, Berlin, Germany
A new method for performing scanning tunneling potentiometry of semiconductor heterojunctions is described. The method yields a direct measure of the electrostatic potential distribution across the interface, with microscopic resolution. The measurement is accomplished by scanning the probe tip at constant sample-tip separation across the junction, and adjusting the sample-tip voltage to maintain a constant tunnel current. An example is given of potentiometry across a GaAs pn-junction.