IN-SITU DIRECT IMAGING OF SCANNING TUNNELING MICROSCOPE TIP APEX

In situ and direct imaging of the scanning tunneling microscope (STM) tip apex is made possible by nano needle structures grown on the sample surface (needle formation and tip imaging: NFTI). The nano needle structures, which extend several nms and are sharper than the tip, are formed on the silicon(111)7 x 7 surfaces by applying high negative voltages to the tip. The relationship between the tip apex feature and the STM image is investigated and it is experimentally confirmed that an atomically sharp tip apex results in STM images with atomic resolution.