Scott A. Speakman

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The in situ crystallization of the incorporated amorphous semiconductor within the multimaterial fiber device yields a large decrease in defect density and a concomitant five-order-of-magnitude decrease in resistivity of the novel metal-insulator-crystalline semiconductor structure. Using a post-drawing crystallization process, the first tens-of-meters-long(More)
The reaction pathway and kinetics of CuGaSe2 formation were investigated by monitoring the phase evolution of temperature ramp annealed or isothermally soaked bilayer glass/GaSe/CuSe precursor film using time-resolved, in situ high-temperature X-ray diffraction. Bilayer GaSe/CuSe precursor films were deposited on alkali-free thin glass substrates in a(More)
Two novel, asymmetric methanofullerenes are presented, which self-assemble in cyclohexane upon thermal cycling to 80 °C. We show that, through the introduction of a dipeptide sequence to one terminus of the dendritic methanofullerene, it is possible to transform the assembly behavior of these molecules from poorly formed aggregates to high-aspect-ratio(More)
In-situ X-ray diffraction was used to study structural transformations in several n=3 Aurivilliustype phases: Bi4Ti3O12, Bi2La2Ti3O12, Bi2Sr2Nb2TiO12, Bi2Sr2Nb2AlO11.5 and Bi2Sr2Nb2GaO11.5. Order-disorder transformations have been linked to transitions to fast ion conduction in certain oxygen-deficient phases, such as Bi2Sr2Nb2AlO11.5 and Bi2Sr2Nb2GaO11.5.(More)
The reaction rates and formation mechanisms of various n=3 Aurivillius phases were studied. Current research has shown that in order to make phase pure materials via solid-state synthesis, over 100 hours of heat treatment are necessary. A custom high temperature X-ray diffractometer (HTXRD) was utilized to observe in-situ formation reactions. The(More)
XRD patterns of NIST standard reference materials were collected using a gas proportional detector and a linear Position Sensitive Detector (PSD). Incident beam optics used for data collection consisted of a polycapillary X-ray lens, a graded multilayer parabolic X-ray mirror, and programmable divergence slits. Peak position, width, and intensity were(More)
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