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Your search keyword '"McDonald, Anthony E."' showing total 33 results
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33 results on '"McDonald, Anthony E."'

1. Detection of High Energy Ionizing Radiation using Deeply Depleted Graphene-Oxide-Semiconductor Junctions

Author

Ruiz, Isaac, Vizkelethy, Gyorgy, McDonald, Anthony E., Howell, Stephen W., Thelen, Paul M., Goldflam, Michael D., and Beechem, Thomas E.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Graphene's linear bandstructure and two-dimensional density of states provide an implicit advantage for sensing charge. Here, these advantages are leveraged in a deeply depleted graphene-oxide-semiconductor (D2GOS) junction detector architecture to sense carriers created by ionizing radiation. Specifically, the room temperature response of the silicon-based D2GOS junction is analyzed during irradiation with 20 MeV Si4+ ions. Detection was demonstrated for doses ranging from 12-1200 ions with device functionality maintained with no substantive degradation. To understand the device response, D2GOS pixels were characterized post-irradiation via a combination of electrical characterization, Raman spectroscopy, and photocurrent mapping. This combined characterization methodology underscores the lack of discernible damage caused by irradiation to the graphene while highlighting the nature of interactions between the incident ions and the silicon absorber., Comment: 15 pages, 4 figures

Published
2022
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4. Thermal conductivity of (Ge2Sb2Te5)1−xCx phase change films.

Author

Scott, Ethan A., Ziade, Elbara, Saltonstall, Christopher B., McDonald, Anthony E., Rodriguez, Mark A., Hopkins, Patrick E., Beechem, Thomas E., and Adams, David P.

Subjects
THERMAL conductivity, PHASE change memory, HEAT capacity, PHASE change materials, THERMAL stability, CONCENTRATION functions
Abstract

Germanium–antimony–telluride has emerged as a nonvolatile phase change memory material due to the large resistivity contrast between amorphous and crystalline states, rapid crystallization, and cyclic endurance. Improving thermal phase stability, however, has necessitated further alloying with optional addition of a quaternary species (e.g., C). Here, the thermal transport implications of this additional species are investigated using frequency-domain thermoreflectance in combination with structural characterization derived from x-ray diffraction and Raman spectroscopy. Specifically, the room temperature thermal conductivity and heat capacity of (Ge 2 Sb 2 Te 5) 1 − x C x are reported as a function of carbon concentration (x ≤ 0.12) and anneal temperature (T ≤ 350 ° C) with results assessed in reference to the measured phase, structure, and electronic resistivity. Phase stability imparted by the carbon comes with comparatively low thermal penalty as materials exhibiting similar levels of crystallinity have comparable thermal conductivity despite the addition of carbon. The additional thermal stability provided by the carbon does, however, necessitate higher anneal temperatures to achieve similar levels of structural order. [ABSTRACT FROM AUTHOR]

Published
2020
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7. Size dictated thermal conductivity of GaN.

Author

Beechem, Thomas E., McDonald, Anthony E., Fuller, Elliot J., Talin, A. Alec, Rost, Christina M., Maria, Jon-Paul, Gaskins, John T., Hopkins, Patrick E., and Allerman, Andrew A.

Subjects
*THERMAL conductivity, *GALLIUM nitride, *THERMAL properties, *REFLECTANCE, *THICKNESS measurement
Abstract

The thermal conductivity of n- and p-type doped gallium nitride (GaN) epilayers having thicknesses of 3-4 µm was investigated using time domain thermoreflectance. Despite possessing carrier concentrations ranging across 3 decades (1015-1018 cm-3), n-type layers exhibit a nearly constant thermal conductivity of 180W/mK. The thermal conductivity of p-type epilayers, in contrast, reduces from 160 to 110W/mK with increased doping. These trends--and their overall reduction relative to bulk--are explained leveraging established scattering models where it is shown that, while the decrease in p-type layers is partly due to the increased impurity levels evolving from its doping, size effects play a primary role in limiting the thermal conductivity of GaN layers tens of microns thick. Device layers, even of pristine quality, will therefore exhibit thermal conductivities less than the bulk value of 240 W/mK owing to their finite thickness. [ABSTRACT FROM AUTHOR]

Published
2016
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9. Tunable Infrared Devices via Ferroelectrics: Tunable Infrared Devices via Ferroelectric Domain Reconfiguration (Advanced Optical Materials 24/2018)

Author

Beechem, Thomas E., primary, Goldflam, Michael D., additional, Sinclair, Michael B., additional, Peters, David W., additional, McDonald, Anthony E., additional, Paisley, Elizabeth A., additional, Kitahara, Andrew R., additional, Drury, Daniel E., additional, Burckel, D. Bruce, additional, Finnegan, Patrick S., additional, Kim, Jong‐Woo, additional, Choi, Yongseong, additional, Ryan, Philip J., additional, and Ihlefeld, Jon F., additional

Published
2018
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10. Tunable Infrared Devices via Ferroelectric Domain Reconfiguration

Author

Beechem, Thomas E., primary, Goldflam, Michael D., additional, Sinclair, Michael B., additional, Peters, David W., additional, McDonald, Anthony E., additional, Paisley, Elizabeth A., additional, Kitahara, Andrew R., additional, Drury, Daniel E., additional, Burckel, D. Bruce, additional, Finnegan, Patrick S., additional, Kim, Jong‐Woo, additional, Choi, Yongseong, additional, Ryan, Philip J., additional, and Ihlefeld, Jon F., additional

Published
2018
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11. Chelant Enhanced Solution Processing for Wafer Scale Synthesis of Transition Metal Dichalcogenide Thin Films

Author

Ionescu, Robert, primary, Campbell, Brennan, additional, Wu, Ryan, additional, Aytan, Ece, additional, Patalano, Andrew, additional, Ruiz, Isaac, additional, Howell, Stephen W., additional, McDonald, Anthony E., additional, Beechem, Thomas E., additional, Mkhoyan, K. Andre, additional, Ozkan, Mihrimah, additional, and Ozkan, Cengiz S., additional

Published
2017
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13. Oxidation of ultrathin GaSe

Author

Beechem, Thomas E., primary, Kowalski, Brian M., additional, Brumbach, Michael T., additional, McDonald, Anthony E., additional, Spataru, Catalin D., additional, Howell, Stephen W., additional, Ohta, Taisuke, additional, Pask, Jesse A., additional, and Kalugin, Nikolai G., additional

Published
2015
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27. Design of the target area for the National Ignition Facility

Author

Foley, Richard J., primary, Karpenko, Victor P., additional, Adams, Chris H., additional, Patel, C. S., additional, Pittenger, L. C., additional, Lee, F. Dean, additional, Reitz, T. C., additional, Hibbard, Wilthea J., additional, Horton, W. R., additional, Trummer, David J., additional, Tobin, Michael T., additional, McDonald, Anthony E., additional, Wavrik, R. W., additional, and Pittman, P. C., additional

Published
1997
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