SCANNING MICROSENSORS FOR NANOTECHNOLOGY

One of the most significant developments in the realm of nanotechnolog y during the 1980s was the invention of the scanning tunnelling micros cope. This event triggered the evolution of a whole family of scanning probe microscopes (SPMs), all based on the use of proximal microsenso rs with very high lateral as well as vertical resolutions, which even allow atoms to be imaged. The properties sensed range from quantum tun nelling currents, through interatomic and van der Waals forces, to the evanescent electromagnetic field. The principal application is imagin g by the measurement of topography, but for many of the microsensors i nteraction with the surface is dependent on material properties, thus allowing a spectroscopic mode of use as well. The principles of severa l microsensors and associated SPMs are examined. The requirements for the traceable calibration of SPMs are discussed, and progress towards the development of calibration artifacts presented.