In this work, electron beam induced current (EBIC) and scanning photocurrent microscopy (SPCM) were used to quantitatively investigate the electronic properties of silicon nanowire devices. For the first time, it was shown that minority carrier diffusion lengths in phosphorous-doped silicon nanowires are significantly reduced from their bulk values because of...
Increasing interest in long-life bone implants with reduced mechanical properties reducing the stress-shielding effect and a structure mimicking bone porous architecture has encouraged study and development of fabrication methods for porous NiTi. The main objective of this work was to advance these goals by developing new processing procedures for porous...
Motivated by performance requirements of future medical stent applications, experimental research addresses the design of novel TiNi-based, superelastic shape-memory alloys employing nanoscale precipitation strengthening to minimize accommodation slip for cyclic stability and to increase output stress capability for smaller devices. Using a thermodynamic database describing the B2 and L21 phases...
Liquid metal melt-lubrication of high-power and high-speed sliding electrical contacts improves electrical current collection and reduces friction. However, armature material loss may cause transition to arcing or plasma contact. Boundary lubrication of the sliding contact with low melting-point alloys can provide comparable improvement in current collection at reduced temperatures. Bismuth,...
The measurement of weak adhesive energies has previously been difficult to obtain. To measure these energies, I designed a technique that uses the combined sensitivities of both a quartz crystal resonator and the inflation of an elastomeric polymer membrane. The surfaces of the quartz crystal and/or the membrane are modified...
The use of composites is increasing as they afford scientists and engineers the ability to combine the advantageous properties of each constituent phase, e.g. metal ductility and ceramic stiffness. With respect to materials design, biomimetics is garnering increasing attention due to the complex, yet efficient, natural microstructures. One such biomimetic,...
The current trend of ceramic nanotechnology has motivated an ever-increasing need to achieve exquisite control over size, shape, and spatial confinement for functional oxide architectures, in an equivalent manner demonstrated for semiconductors. However, the unique nature of ceramics has posed major challenges for most traditional nanofabrication technologies, putting the development...
Metal nanoparticles in polymeric matrices are of particular scientific interest due to their useful ability to self-assemble into complex nanocomposites. Recent examples involve using ultrathin diblock copolymers coupled with metal nanoparticles in the fabrication of novel electronic, magnetic and photonic devices. As this ordering process takes place far from equilibrium...
Two main topics are addressed in this dissertation: (1) adhesion in hydrogels; (2) interfacial interactions between model glassy polymers. A self-assembly technique for the formation of hydrogels from acrylic triblock copolymer solutions was developed, based on vapor phase solvent exchange. Structure formation in the gels was characterized by small angle...
A novel cryogenic variable temperature UHV STM has been constructed and utilized to investigate the dynamical behavior of isolated organic molecules covalently bound to silicon surfaces.
The microscope can be operated from 8-300 K, and exhibits extremely low drift rates. A new design has been implemented for the rails (used...