Development of low temperature ultrahigh vacuum atomic force microscope/scanning tunneling microscope

A low temperature ultrahigh vacuum atomic force microscope (UHV-AFM) has be en developed, which allows the sample to be cooled from room temperature to lower than 28 K during observation and can be attached to the conventional UHV-AFM. Atom resolved non-contact atomic force microscopy (NC-AFM) images of the Si(100) surface were obtained at 120 K and 50 K using the produced low temperature UHV-AFM/STM, and the Si(100) dimer structure was successful ly observed for the first time by NC-AFM. It was found that the Si(100)-c(4 x 2) structure mainly covered the area at 120 K, but the p(2 x 2) structur e area increased at 50 K.