ATOMIC-FORCE MICROSCOPY IN ULTRAHIGH-VACUUM

Since its invention in 1986, atomic force microscopy (AFM) has been us ed mainly in ambient conditions. Recent advances in instrumentation ha ve fostered the application of AFM in ultrahigh vacuum (UHV). AFM expe riments performed in UHV have led to a better understanding of the tip -sample interaction. This article reviews the theory related to achiev ing true atomic resolution of AFM in UHV in both contact- and nonconta ct-modes. Preliminary experimental results with unprecedented resoluti on on KCl and Si(111)7 x 7 achieved by noncontact AFM in UHV are prese nted.