Development of Atomic Force Microscope

Abstract

Since AFM was developed in 1986, much work has been done to enhance its resolution. In recent years Tuning forks are being used as a cantilever. Tuning fork as a tip-sample separation detector provides excellent stability and low thermal noise while measuring forces in pN range. A piezoelectric quartz tuning fork allows tip-sample separation detection without use of any optics. A tuning fork based dynamic Atomic Force Microscope for force measurements have been developed. An X-Y-Z nano-positioner for sample coarse and fine approach has been developed. Current measurements have been done to test the overall stability of the set-up and tip-sample junction. The typical amplitude-distance curves are recorded for on-resonance operation with a tungsten tip mounted on micro-machined quartz tuning forks commercially available in the market. Under the on resonance condition, interaction force changes amplitude, frequency and phase of the tuning fork. A servo controller for the AFM and its automation using LABVIEW is developed. Once we are ready with the LabVIEW programme for scanning, we want to use this AFM to image in liquid.