Events

Low cost and flexible integrated circuits will enable many new applications for our daily life. Amorphous silicon (a-Si) is the current material of choice for low-cost thin film transistors (TFTs) that are widely used as switching devices in active-matrix liquid-crystal displays. Organic (molecular crystals or polymeric) semiconductors with the advantages of flexibility and compatibility with solution-based low-cost processes (e.g. spin coating and ink jet printing) and plastic substrates are major candidates.

This work demonstrates some novel procedures for joining multiple solutions of the Einstein field equation in a way which creates a new analytical tool for studying them. Joining known solutions along shells ensures that we have solutions off the boundary. In 1985 Dray and 't Hooft showed how to use use spherically symmetric shells of massless matter to join spacetime regions with Schwarzschild geometry. We demonstrate here how to use these solutions to draw information-rich Penrose diagrams usable for investigating the characteristics of the solutions.

The intracellular environment is a dynamic, multi-component fluid, with relaxations spanning a broad range of length and time scales. Understanding the molecular basis of intracellular transport is a challenging problem due to the myriad chemical species and physical processes at play. In my talk, I will discuss some of our recent experiments to study the motions of mitochondria in living yeast cells, and how these motions depend on the properties of the intracellular matrix.

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BaCuSF is a p-type transparent conductor. This thesis project investigated whether Cu vacancies were responsible for the conductivity of the undoped material. BaCuSF thin films were grown by pulsed laser deposition and characterized by several different techniques. Films deposited with a small amount of excess Cu were more resistive, which supports the hypothesis.

We present a technique capable of producing subwavelength focal spots in planar nonresonant structures not limited to the near-field of the source. The approach combines the diffraction gratings that generate the high-wave-vector-number modes and planar slabs of homogeneous anisotropic metamaterials that propagate these waves and combine them at the subwavelength focal spots.

Density functional calculations have been performed to
elucidate the source of unintentional p-type conductivity in nominally
stoichiometric BaCuChF (Ch = S, Se, Te) wide bandgap semiconductors. Formation
enthalpies and transition levels (activation energies) were found for all
vacancies and antisites, and for some interstitials. Results of this initial
study suggest that of all hole-producing point defects, copper vacancies are
the easiest to form. The formation energy of copper vacancies decreases with increasing