Liwei Lin (Advisor)

Two dimensional electron gas (2DEG) and hole gas (2DHG) can be induced at the interface of epitaxial AlGaN/GaN due to spontaneous and piezoelectric polarization. Such electronic system features high transport mobility, carrier density and piezoelectric sensitivity. Mechanical strain and vibrations of devices can be transduced to electronic signals in embeded 2DEG for further processing. In this project, we study physical properties of this strongly-coupled electromechanical system, and develop possible devices such as pressure sensor, MEMS resonator, ultrasonic transducer, etc....

This work presents the first demonstration of atomic layer deposition (ALD) ruthenium oxide (RuO2) and its conformal coating onto vertically aligned carbon nanotube (CNT) forests as supercapacitor electrodes. Specific accomplishments include: (1) successful demonstration of ALD RuO2 deposition, (2) uniform coating of RuO2 on a vertically aligned CNT forest, and (3) an ultra-high specific capacitance of 100 mF/cm2 from prototype electrodes with a scan rate of 100 mV/s. Advantages of the ALD method include precise control of the RuO2 layer thickness and composition without the use of...

Mixing in microfluidic devices has long presented challenges due to the lack of significant turbulence at low Reynolds numbers. Although ample theoretical work has demonstrated methods to enhance microfluidic mixing (e.g., increasing vorticity, arranging chaotic flow profiles), many of these methods are difficult to achieve in practical microfluidic devices, requiring 2D approximations to fully 3D mixing enhancements. In this work, we will show that various designs for enhanced mixing are easily achievable using 3D printing. We will compare the performance of several different mixer...

Electro-Hydrodynamic (EHD) Printing based direct write method has been demonstrated that the efficient fabrication process for the fast-response and super-thin silver (Ag) passive temperature sensor. For the direct write Ag passive temperature sensor, biological polymer was applied for efficient Ag nanostructure formation, and the EHD Printer directly eject and deposit this Ag precursor ink on the substrate. During annealing process this Ag passive sensor rapidly produce the 2D nanoparticles from the air/water interface and directly sintered to Ag thin film patterns in 200oC. This...