| Silicon-based thin films, in the form of single crystal nanomembrane, crystalline silica (quartz), and amorphous silicon dioxide (glass) have been studied to explore their potential as chemical or biological sensors. A "sandwiched drilling" scheme is proposed to make extremely small and smooth pores in glass and quartz slides for planar patch clamping. Unique crater features can also be realized. These chips have the advantage of increased seal resistance and hence reduced measurement noise. In the case of quartz, which is piezoelectric, we can initiate shear-mode vibration to probe mechanosensitive ion channels. Another focus of this research is the fabrication of rolled-up tubular structures using Si/SiGe-on-insulator (SGOI) nanomembranes. The rolling is caused by lattice-mismatch induced strain sharing. Chemical adsorption to the open tube surface can create a stress imbalance that deforms the tube. Our simulation suggests that such a deformation will result in distinctive far-field radiation patterns in the terahertz (THz) range. Finally, we demonstrate using Si/SiGe microbutes as a topographical guidance cue for in vitro neuron outgrowth. Not only is the substrate biologically viable, but also can the micrometer-sized 3D confinement of a tube attract neurons. Coupled with selective spatial seeding, growth within a tube can further be limited to a single axon. Moreover, the tube feature resembles the natural myelin, both physically and electrically and can potentially isolate the neurites inside the tube from extracellular solutions. |
