Atomic Force Microscopy in Ultrahigh Vacuum

Since its invention in 1986, atomic force microscopy (AFM) has been used mainly in ambient conditions. Recent advances in instrumentation have fostered the application of AFM in ultrahigh vacuum (UHV). AFM experiments performed in UHV have led to a better understanding of the tip-sample interaction. This article reviews the theory related to achieving true atomic resolution of AFM in UHV in both contact- and noncontact-modes. Preliminary experimental results with unprecedented resolution on KCl and Si (111)7×7 achieved by noncontact AFM in UHV are presented