- Nanostructuring with Electrolytical STM and AFM
- Readout for Massively Parallel AFM
- Compact AFMs
- Study of SACE with AFM
Nanostructuring with Electrolytical STM
Scanning probe microscopes (SPM), originally used for imaging, have been successfully used to modify surfaces at the nanometer scale. It has been shown that an STM tip or a metal tool operating inside an electrolyte can be used to modify surfaces locally. As the deposition / etching are controlled by electrode potentials, it is a relatively simple process. This method is applicable to a large number of systems and another advantage, true for all SPM systems, is that it is possible to view the modified surface in-situ. Our goal is to study the localized deposition of noble metals like Pt on ideal surfaces like HOPG and gold and also on non-ideal surfaces like BDD (boron doped diamond). Nanoparticles of noble metals are of interest to electrochemists for their catalytical properties.
A home built STM, based on the Besocke principle, is used for experiments in electrolyte. The image shows platinum deposited by using nanosecond pulses on gold (Au (111)).
Readout for Massively Parallel AFM
Monolithic or quasi monolithic XY, XYZ piezo stages have been designed and fabricated. Stages have range of 10 to 20 µm in x,y and 30 to 50 µm in z. Novel techniques like lever mechanism, geometry and bimorph effects have been used to amplify the piezo motion and flexure hinges have been incorporated in the stages. Analytical and Finite Element Analysis is used to study and optimise the stages. The stages are cut out of piezo plates by laser cutting.
Piezoelectric cantilevers (provided by Nikon, Japan) are used which eliminates bulky optics. Apart from self sensing, these cantilevers can also be used for feedback actuation with high bandwidth.
Credit Card AFMs have been used to demonstrate position sensing in conjunction with nanometer gratings. A promising application in the field of micro robotics is to use AFMs mounted on micro robots for tracking / positioning with nanometer precision. We have successfully demonstrated Tracking Nanostructures with Microrobots using AFM.
Study of SACE with AFM