2013 Theses Doctoral

The integration of active silicon components in polymer microfluidic devices

Grad, Michael

Early microfluidic devices borrowed technology from established CMOS microfabrication, and were therefore structurally similar to silicon computer chips. In the late 1990s, George Whitesides' group pioneered a cheaper, mass producible polymer device fabrication technique called 'soft lithography' that revolutionized modern microfluidics. This dissertative work has been focused on re-introducing silicon as a common material in microfluidic devices, but as an active component instead of a structural one. These active components exploit the optical properties, electronic properties, and optoelectronic properties of silicon. The optical properties of silicon are utilized in the integration of silicon nanophotonic ring resonators as refractive index sensors embedded in microfluidic channels. The electronic properties of silicon are utilized in the fabrication of an ultra-thin Schottky diode for use as a transmission radiation particle detector for focused ion-beams. Finally, the optoelectronic properties of silicon are used as a photoconductive layer in light-induced dielectrophoretic manipulation of cells. These three projects are combined to investigate optofluidic sensing and manipulation, with potential radiobiological applications.