Towards High-Speed Scanning Tunneling Microscopy

Doctoral Thesis

In this thesis, two routes towards high-speed scanning tunneling microscopy (STM) are described. The first possibility for high-speed scanning that is discussed is the use of MEMS (Micro-Electro Mechanical Systems) devices as high-speed add-ons in STM microscopes. The functionality of these devices is shown using finite-element simulations, combined with measurements of their resonance frequency and actuation range. Tip deposition was done using EBID (Electron-Beam Induced Deposition) which allowed the first tunneling experiments with these high-speed STM scanners. Next, a dedicated STM design is presented that allows incorporation of a counter piezo element, which allows both force and torque compensation during STM measurements. The mechanical behaviour of the scanner as a function of scanning- and counter-piezo actuation is discussed. It is shown how image deformation, induced by internal scanner vibrations that are excited by the scanning motion of the piezo element, can be...Show moreIn this thesis, two routes towards high-speed scanning tunneling microscopy (STM) are described. The first possibility for high-speed scanning that is discussed is the use of MEMS (Micro-Electro Mechanical Systems) devices as high-speed add-ons in STM microscopes. The functionality of these devices is shown using finite-element simulations, combined with measurements of their resonance frequency and actuation range. Tip deposition was done using EBID (Electron-Beam Induced Deposition) which allowed the first tunneling experiments with these high-speed STM scanners. Next, a dedicated STM design is presented that allows incorporation of a counter piezo element, which allows both force and torque compensation during STM measurements. The mechanical behaviour of the scanner as a function of scanning- and counter-piezo actuation is discussed. It is shown how image deformation, induced by internal scanner vibrations that are excited by the scanning motion of the piezo element, can be reduced using force- or torque compensation. We show that, using Fourier analysis, it is possible to determine the optimal compensation scheme for each excited internal resonance of the scanner.Show less

Counter piezo element

High-speed STM

MEMS

Scanning probe microscopy