The primary objective of this thesis was to fabricate nanostructures in glass substrates and silicon nitride membranes that can be used as channels or conduits for electrokinetic flows. The objective was divided into two sub-tasks: (1) fabricate a hybrid microfluidic-nanofluidic device in glass substrates with embedded microelectrodes for the study of induced electroosmotic flow within nanochannels; (ii) the fabrication of solid-state nanopores in silicon nitride membranes with the use of a transmission electron microscope. For the micro/nanofluidic device, several parameters where investigated such as nanochannel etch time, bonding pressure, nanochannel spacing, and PDMS ratio. Fabrication was done with standard UV photolithography processes with borosilicate glass being the substrate for both device layers. Fine-tuning the photolithography parameters solved various problems with the device fabrication. Devices performance was characterized by use of a fluorescence microscope to verify qualitative fluid motion. Nanopore fabrication was performed in STEM mode of a Tecnai F20 TEM. Results showed that a nanopore with a diameter of ~5 nm can be fabricated with a 2 minute etch time. Slit-like nanopores were fabricated using a circular beam while the stage was subject to systematic movement called drifting. Control of nanopore fabrication parameters allowed for fabrication of nanopore arrays in various configurations.
The Ohio State University