Nanoscale Surface Elemental Analysis by Synchrotron Radiation Based Scanning Tunneling Microscope

Abstract

Scanning Tunneling Microscope (STM) combined with Synchrotron Radiation (SR) allowed to analyze solid surfaces in real space with nanometer scale by inner-shell excitation of a specific energy level under the STM observation. Elemental analysis was successfully accomplished for Ge nano-islands on a Si(111) 7×7 surface by SR-STM. As a next step, remaining diffculties of instability and inaccuracy during measurements were improved. After renewal of a dumper system, a key to solve the diffculties was reduction of emitted electrons. Thus, an insulator-coated tip to shut out the electrons coming from a wide area was developed. Further surface analysis was performed for Cu domain on a Ge(111) 2×8 surface using the new tip. As a result, elemental analysis between Cu domains and the surrounding Ge surface was achieved. It has been shown that SR-STM provides new possibilities of nanoscale surface analysis.