A new technique for spectroscopic investigation of subsurface interface electronic structure has been developed. The method, ballistic electron emission microscopy (BEEM), is based on scanning tunneling microscopy. BEEM makes possible, for the first time, direct imaging of subsurface interface properties with nanometer spatial resolution. We report on the first application of BEEM to subsurface Schottky-barrier interfaces.

• Received 10 December 1987

DOI:https://doi.org/10.1103/PhysRevLett.60.1406