Albert P. Pisano (Advisor)

Despite commercial availability since the 1950’s, silicon strain sensors have not experienced the same success as other microdevices, such as accelerometers, pressure sensors, and inkjet heads. Strain sensors measure mechanical deformation and could be used in many structural components, improving safety, controls, and manufacturing tolerances. This thesis examines major strain sensing techniques and highlights both advantages and disadvantages of each. MEMS resonant strain gauges are identified to have superior performance over many traditional strain gauges in terms of sensitivity...

Multi-functional fibers by means of direct-write near-field electrospinning process have been developed for versatile applications on a wide variety of substrates, including flexible ones. Several mask-less lithographoy techniques have been established by using the direct- write fibers in dry etching, wet etching and lift-off processes. By selecting the proper functional materials, electrospun direct-write fibers have been demonstrated in prototype working devices, such as large array piezoelectric nanogenerators made of polymeric PVDF (Polyvinylidene fluoride) and direct-write micro...

The advancement of renewable energy technologies is critical due to the unsustainable nature of currently used energy sources and the need to meet increasing energy demands. A broad and diverse energy plan is important for long term energy independence and stability. Geothermal energy sources including hydrothermal systems and enhanced geothermal systems (EGS) should play a key role in this energy plan. Geothermal energy is the most reliable, currently developed, schedulable alternative energy source. It is estimated that improvements in these systems have the potential to...

Harsh environment applications include high temperature, pressure and mechanical shock. Aluminum nitride is a strong ceramic material with very good high temperature survivability. It also has piezoelectric properties that can be used for sensing applications and it can be deposited with good control as thin polycrystalline film for the fabrication of micro-electromechanical systems. In this dissertation, optimized deposition parameters for aluminum nitride films and characterization techniques for film stress gradients are investigated. Furthermore, two diff...