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Focus On Materials
Materials Day 2006 - Posters
Nanofabrication and MEMS
- H05 - Molecular Ruler Lithography using Multilayer Sacrificial Host Structures Fabricated using Contact, Electron Beam and Deep Ultraviolet Lithography Techniques
S. Subramanian, J. M. Catchmark
Abstract: Molecular ruler nanolithography is a unique process capable of extending the achievable resolution of conventional lithography.This is accomplished by patterning functional host structures whose dimensions can be tailored by systematically assembling engineered organic molecules of precise length on their surface,creating a template for producing features with reduced dimensions.Here we describe a novel method for implementing molecular ruler nanolithography using a sacrificial multilayer host structures.This approach provides several advantages including the potential for high yield processing,simplified removal of the host material,isolation of the host material from the substrate surface and the capability to pattern thicker daughter features.We have demonstrated this process using contact and electron beam lithography to pattern the host structures and shown its compatibility with deep UV lithogarphy.Isolated sub-40nm wide chromium lines have been successfully fabricated.
- H06 - Motor Surface Processing Approaches
V. Verma, W. O. Hancock, J. M. Catchmark
Abstract: Kinesin and Microtubule system transport intracellular cargo and position orgenelles in eukaryotic cells. Kinesin motors move directionally along microtubules using the energy of hydrolysis of ATP to ADP. Forces generated by the kinesin motors are sufficient to power synthetic devices. To realize useful work from the directional motion of biomolecular protein system it is imperative to specifically immobilize kinesin motors and to align microtubules on the device. Traditional device fabrication processes such as lithography is not considered compatible with the biological proteins. For hybrid biological and synthetic system it is necessary to integrate device fabrication and protein patterning. We performed a series of experiments to investigate the compatibility of resist PMMA its developer and stripper with blocking protein casein, motor protein kinesin and microtubules. From our studies we have designed a process for hybrid biological and synthetic system integration.
- H07 - Microwave Synthesis of Aligned Carbon Nanotubes
J. Cheng, D. Agrawal, Y. Zhang
Abstract: Using a 2.45 GHz wave-guided cavity, in a single mode TE103 excitation, we were able to physically locate a small sample separately at the H (magnetic) node (where the E field is nearly zero), and the E (electric) node (where H field is nearly zero). Various materials, such as ceramics, powdered metals and composites, exhibited remarkable differences in their microwave heating behaviors [1,2]. Well-aligned multiwall carbon nanotubes (CNTs) have been synthesized on Fe-coated Si wafers in this single mode microwave cavity using acetylene as the carbon source at temperature ranges of 700-800 °C in 5-10 minutes. The average length of microwave synthesized CNTs was around 10-15 microns. The diameter of microwave synthesized CNTs could be controlled form 30 nm to 150 nm by adjusting the acetylene/hydrogen ratio. Higher acetylene concentration produced larger diameter CNTs.
- H08 - Prospects for Nanowire Sculptured Thin Film Devices
S. Pursel, O. Ezekoye, M. W. Horn
Abstract: The concept of Sculptured Thin Films (STFs) emerged during the mid-1990s. STFs are assemblies of parallel curvilinear nanowires that can be fabricated by design using physical vapor deposition techniques, such as thermal and arc evaporation, sputtering, and pulsed laser ablation. The combination of large thickness (>3 µm), large-area uniformity (75 mm diameter), and high growth rate (up to 0.4 µm/min) in assemblies of complex-shaped nanowires on lithographically defined patterns has been recently achieved. In this poster we review the current status and prospects for the future of engineered nanowire STFs. The ability to sculpture the nanowires out of virtually limitless variety of solid materials, coupled with micro- and macroscale 1D and 2D topographic substrates points towards new vistas of photonic, fluidic and sensor devices. Applications include: nanowire assemblies for bionanotechnology, because nanopatterning of surfaces is known to influence protein adsorption and cell behavior; photonic bandgap engineering, because complex periodic features can be lithographically etched on large-area substrates, with lattice sizes >50 nm; and sensors for bioremediation, where patterning can facilitate bioreduction of FeOx or CrOx STFs thus indicating the proper environment for reduction of hexavalent uranium or chromium. Recent results will be presented, including new optical data for Bragg reflection of right-handed circularly polarized light in a SnOx film deposited at room temperature and STFs made out of polymers. We will also show examples of STFs made out of metals, semiconductors, insulators.
- H09 - Surface Induced "Ice-Like" Water at Atmospheric Pressure and Room Temperature - the Complete Self-Association of Water on Native Silicon Dioxide
D. B. Asay, S. H. Kim
Abstract: Adsorption of water on clean native silicon dioxide surfaces via ATR-FTIR has elucidated a completely self-associated water layer. The adsorption isotherm for water was also determined. The growth of completely self-associated water (ice-like) layer continues until the partial pressure of water is approximately 35% of the saturated pressure. Between 35% and 60% the adsorbing water transitions from an ice-like structure to a more liquid like arrangement. At even higher humilities, water appears to adsorb and conform to liquid IR spectra, adsorbing onto the ice-like layer. Because of the complete self-association, the ice-like layer is believed to have a higher surface energy than liquid water due to increased cohesive forces. This behavior is used to develop a model to predict the stiction or adhesion behavior that is observed in the AFM. Both the increase and decrease in the adhesive force as a function of humidity are explained giving insite into phenomena not well understood.
- H11 - Micro and Nanomechanical Behavior
C. L. Muhlstein
Abstract: The degradation of materials under cyclic loading conditons, commonly known as fatigue, is one of the most commonly encoutered modes of failure during service. The mechanistic understanding of fatigue together with the damage/fracture mechanics to describe its effects at continuum dimensions have recently been applied to micon-scale devices known as microelectromechanical systems (MEMS) that utilize thin film forms of the structural material. The Muhlstein research group studies the mechanical behavior of both bulk and thin film materials with an emphasis on the mechanisms of fracture and fatigue. Recent research has established the mechanism of fatigue of silicon thin films, which serve as the dominant structural material used in MEMS.
- H12 - Synthesis of "Colloidal Molecule" Assemblies
D. Velegol, C. Snyder, A. Yake
Abstract: Particle assemblies built from the bottom-up have been limited to close-packed structures of the same types of particles. These have been called "colloidal molecules" in the literature. However, even more useful to applications in electronics, optics, and other fields would be particles composed of various materials that could be assembled into more complex shapes, with nanoscale accuracy and reproducibility. Our lab group has developed novel techniques for synthesizing more complex "colloidal molecules" based on fundamental principles of colloid science. We have accurately synthesized colloidal doublets of two different particles types, while avoiding large random aggregates. In addition, we are extending this technique to constructing other particle shapes, such as five particles synthesized in a pyramid-type arrangement, with well-defined and accurate angles between the particles.
URL: http://www.personal.psu.edu/faculty/d/x/dxv9/
