4751.2:
Time-of-Flight Scanning Force Microscopy (TOF-SFM)
Abstract
The main objective is the construction of a time-of-flight mass-spectrometer combined with a state-of-the-art atomic force microscope. The surface is imaged with a dynamic force microscope on the atomic-scale, where the frequency shift of the cantilever-type spring is used as feed-back parameter. Small clusters or ultimately single atoms are picked up by the tip by increasing the force. A fast micromachined, mechanical switch is used to reorientate the tip towards the entrance of the mass-spectrometer. Ionization is achieved by high voltage pulses in combination with heat and laser excitation. The selected ions are analyzed by means of the time-of-flight mass spectrometer. This method gives the opportunity for chemical analysis on the atomic scale.