Optical/electrical micro-methods

Samples are prepared by means of photolithography, that is, the local resolution of the electrical measurement is determined by focused laser radiation. In this context it has to be kept in mind that the high lateral resolution achieved in modern device and micro-system technology and research is mainly due to optical processing, that is, photolithography. Detailed examples for application of photoresist microelectrochemistry, namely the new photoresist nl-droplet method, will be given. 

Dielectrophoretic forces, though, can be induced by means other than an applied electric signal through electrodes. Optical tools can be implemented to modify an applied electric field, making these methods more susceptible for dynamic as opposed to static manipulation of electric fields with surface electrodes. Dielectrophoresis applications are not limited to particulate manipulation either. With properly configured surface-electrode geometry, it is possible to induce fluid motion and create nanoliter-sized droplets. Additionally, dielectrophoretic forces can be utilized to manipulate particles to buUd micro- and nanostructures such as wires. 

What has inspired initial research in microfluidics is similarly driving the research into optofluidics today. The goal is to make smaller features going from micro- to nanoscales in order to fill the gap between top-down and the bottom-up fabrication techniques [7]. Because most devices consist of multiple planar layers, there is motivation to develop 3-D fabrication or assembly methods for both optical and electrical components. The ultimate goal is an easy and simple technique which works well with a variety of materials and on different scales. The most successful devices up to date rely on fundamental principles of both optics and fluidics in order to avoid as many of components as possible, leaving those devices only with essentials to carry out their fimctions. 

The principle and the research progress in the electrophoretic sol-gel deposition technique, which is combined sol-gel method for particle preparation and electrophoretic deposition of the sol-gel derived particles, have been described. In the principal, (1) preparation of particles by the sol-gel method, (2) deposition of particles by electrophoresis, (3) constant-voltage and constant-current deposition, and (4) solvent and electrification are introduced, hi the practical application, (1) silica thickfihns, (2) titania thick films, (3) polysilsesquioxane thick films, and (4) template-based oxide nanorods are illustrated. The electrophoretic sol-gel deposition technique offers the advantages of functional coatings in various research fields such as chemically and mechanically protective, electrically conductive, photocatalytic and bioactive materials, and it expands the possibility of fabricating optical components and ahgned micro- and nanostructures. 

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