Carbon fibre tips for scanning probe microscopy based on quartz tuning fork forcesensors

Abstract

We report the fabrication and the characterization of carbon fibre tips for use incombined scanning tunnelling and force microscopy based on piezoelectric quartztuning fork force sensors. We find that the use of carbon fibre tips results in aminimum impact on the dynamics of quartz tuning fork force sensors, yielding ahigh quality factor and, consequently, a high force gradient sensitivity. This highforce sensitivity, in combination with high electrical conductivity and oxidationresistance of carbon fibre tips, make them very convenient for combined andsimultaneous scanning tunnelling microscopy and atomic force microscopy measurements.Interestingly, these tips are quite robust against occasionally occurring tip crashes. Anelectrochemical fabrication procedure to etch the tips is presented that produces asub-100-nm apex radius in a reproducible way which can yield high resolution images.