15 research outputs found
Multiple Schottky Barrier-Limited Field-Effect Transistors on a Single Silicon Nanowire with an Intrinsic Doping Gradient
No full textElectrical Spin Injection and Detection in Silicon Nanowires with Axial Doping Gradient
No full textThe
interest in spin transport in nanoscopic semiconductor channels
is driven by both the inevitable miniaturization of spintronics devices
toward nanoscale and the rich spin-dependent physics the quantum confinement
engenders. For such studies, the all-important issue of the ferromagnet/semiconductor
(FM/SC) interface becomes even more critical at nanoscale. Here we
elucidate the effects of the FM/SC interface on electrical spin injection
and detection at nanoscale dimensions, utilizing a unique type of
Si nanowires (NWs) with an inherent axial doping gradient. Two-terminal
and nonlocal four-terminal lateral spin-valve measurements were performed
using different combinations from a series of FM contacts positioned
along the same NW. The data are analyzed with a general model of spin
accumulation in a normal channel under electrical spin injection from
a FM, which reveals a distinct correlation of decreasing spin-valve
signal with increasing injector junction resistance. The observation
is attributed to the diminishing contribution of the d-electrons in
the FM to the injected current spin polarization with increasing Schottky
barrier width. The results demonstrate that there is a window of interface
parameters for optimal spin injection efficiency and current spin
polarization, which provides important design guidelines for nanospintronic
devices with quasi-one-dimensional semiconductor channels
Creighton University Omaha, Nebraska School of Law Class of 1995
No full textGraduates|Abariotes, Elizabeth S.; Alexander, Jerry P.; Allen, Michelle K.; Anderson, Marcia K.; Ash, Laura M.; Baranko, Tracy A.; Barrett, Thomas S. (President); Bausch, Trenten P.; Bazley, Amy R.; Beck, William G.; Berger, Karl H.; Black, Ralph E.; Bloomingdale, Patrick T.; Bongard, Michael J.; Booth, Robert F.; Brantley, W. Thomas; Brundo, Nicole; Buckman, John B.; Burgess, Laurie E.; Buxton, Cynthia; Byrnes, Michelle T.; Calkins, Scott A.; Chase, Karla A.; Childs, Eric M.; Coleman, Todd C.; Crawford, Nancy L.; Daley, Michael D.; Damski, Elizabeth; de la Lama, Pablo; Dean, Kelly L.; DeVeney, Jean M.; Devine, Michael J.; Donovan, Mary A.; Dotzler, Christal M.; Dowd, Kelley E.; Dowd, Timothy S.; Dvorak, David M.; Elsinger, Janine M.; Emdin, Michael T.; Fagan, Charles D.; Farres, Edelberto; Fiester, David R.; Flanagan, Paul E.; Franzese, Matthew P.; Fritz, Richard R.; Gauer, Keith A.; Gentry, Amy E.; Gill, John F.; Girard, Gina Stella; Girard, Owen E.; Glover-Ettrich, Suzanna G.; Glynn, David T.; Gonzales, Ruben, Jr.; Gottula, Lisa G.; Greenway, Lori A.; Griffin, Patrick J.; Grimm, Stefanie A.; Grinstead, Tracy E.; Gunhus, Kimberly K.; Habush-Dewar, Laura; Haver, John L.; Hearn, Clayton R.; Heim, Geoffrey S.; Henkenius, Michael L.; Henry, Todd W.; Hess, William F.; Horne, Nathan R.; Hurley, Francis P.; Johnson, Douglas A.; Johnson, Laurie L.; Keiper, Monte R.; Kelley, James E.; Kelley, Kevin J.; Kennedy, Leigh Ann; Kenney, Joseph P.; Kerschen, Karla R.; Kimball, Jared C.; Klein, Lawrence S.; Kleinschmidt, Kelly K.; Larkins, James M., III; Lathrop, Christopher J.; Leahy, Michael J.; LeMay, MIchael A.; Lockwood, Brian J.; Logan, Jeffrey R.; Long, Kimberly F.; Lucas, Tory L.; Lutz, Patrick M.; Mahanna, Stephen E.; Malousek, Mark J.; Martey, Pamela M.; McCandless, Erin E.; McClintock, John E.; McGargill, Jennifer A.; Mellor, Michele M.; Meloy, Daniel A.; Merithew, George T.; Meulner, Brian S.; Mikulicz, Timothy D.; Moore, Scott P.; Morgan, Heather; Morrow, Jennifer H.; Morss, Kristin A. (Class Representative); Mulholland, Jennifer; Murphy, Thomas R.; Murray, John M.; Neuharth, Christine A.; Nolte, Bobie A.; O'Brien, Dennis M.; Perales, Jill A.; Petregal, Laura A.; Poe, David C.; Polack, James; Pulk, Brooke E.; Rademacher, Leigh A.; Real, Daniel L.; Reeb, David P., Jr.; Remedios, Anna M.; Ribick, Traci A.; Ridenour, David E.; Routt, Christopher A.; Rowley, Susan C.; Schmidt, Thomas A. K.; Schrant, Melissa A.; Scott, Eric A., IV; Seibel, Michael J.; Shiers, Andrew J.; Shotkoski, Paul M.; Skinner, Matthew L.; Slater, Wendy L.; Speca, Peter J.; Stirek, Michelle Sand; Stock, Jo Ellen K.; Straka, Thomas J.; Streng, Pamela Kaye; Sulentic, John N.; Sullivan, Robert M.; Swanson, Martin W. (Class Representative); Swanson, Rachel A.; Tanko, Brian C.; Ueding, Michelle M.; Vana, Candyce L.; Van Wyk, Douglas J.; Waters, Jonathan P.; Weatherhead, Angela M.; Wessel, Ron W.; Whelan, Deirdre E.; Whited, Stephanie A.; Whitten, Eden T.; Wintroub, David S.; Wood, Nancy A.; Wood, Steven D.; Yamagishi, Daniel G.; Yauger, Brett S.; Zaritsky, Michael A.; Achola, George B. (not pictured); Akins, Samual J. (not pictured); Allred, Rosemarie Lazcano (not pictured); Bima, Kenneth S. (not pictured); Carter, Ann M. (not pictured); Destache, Denise M. (not pictured); Dopheide, Andrew P. (not pictured); Graue, James E. (not pictured); Henderson, Sandy R. (not pictured); Jacoby, Jeffrey J. (not pictured); Lashkajani, Elaine L. (not pictured); Martin, Lisa M. (not pictured); Muncy, Martin B. (not pictured); Spellman, Daniel J. (not pictured); Stolarskyj, Christine A. (not pictured); Wade, Brenda M. (not pictured)|45 x 36 in. (landscape
Technical Note: Comprehensive performance tests of the first clinical real‐time motion tracking and compensation system using MLC and jaws
No full textMultiple Schottky Barrier-Limited Field-Effect Transistors on a Single Silicon Nanowire with an Intrinsic Doping Gradient
No full textIn
comparison to conventional (channel-limited) field-effect transistors
(FETs), Schottky barrier-limited FETs possess some unique characteristics
which make them attractive candidates for some electronic and sensing
applications. Consequently, modulation of the nano Schottky barrier
at a metal–semiconductor interface promises higher performance
for chemical and biomolecular sensor applications when compared to
conventional FETs with ohmic contacts. However, the fabrication and
optimization of devices with a combination of ideal ohmic and Schottky
contacts as the source and drain, respectively, present many challenges.
We address this issue by utilizing Si nanowires (NWs) synthesized
by a chemical vapor deposition process which yields a pronounced doping
gradient along the length of the NWs. Devices with a series of metal
contacts on a single Si NW are fabricated in a single lithography
and metallization process. The graded doping profile of the NW is
manifested in monotonic increases in the channel and junction resistances
and variation of the nature of the contacts from ohmic to Schottky
of increasing effective barrier height along the NW. Hence multiple
single Schottky junction-limited FETs with extreme asymmetry and high
reproducibility are obtained on an individual NW. A definitive correlation
between increasing Schottky barrier height and enhanced gate modulation
is revealed. Having access to systematically varying Schottky barrier
contacts on the same NW device provides an ideal platform for identifying
optimal device characteristics for sensing and electronic applications
Clinical commissioning of an adaptive radiotherapy platform: Results and recommendations
No full textOnline adaptive radiotherapy platforms present a unique challenge for commissioning as guidance is lacking and specialized adaptive equipment, such as deformable phantoms, are rare. We designed a novel adaptive commissioning process consisting of end-to-end tests using standard clinical resources. These tests were designed to simulate anatomical changes regularly observed at patient treatments. The test results will inform users of the magnitude of uncertainty from on-treatment changes during the adaptive workflow and the limitations of their systems. We implemented these tests for the cone-beam computed tomography (CT)-based Varian Ethos online adaptive platform. Many adaptive platforms perform online dose calculation on a synthetic CT (synCT). To assess the impact of the synCT generation and online dose calculation on dosimetric accuracy, we conducted end-to-end tests using commonly available equipment: a CIRS IMRT Thorax phantom, PinPoint ionization chamber, Gafchromic film, and bolus. Four clinical scenarios were evaluated: weight gain and weight loss were simulated by adding and removing bolus, internal target shifts were simulated by editing the CTV during the adaptive workflow to displace it, and changes in gas were simulated by removing and reinserting rods in varying phantom locations. The effect of overriding gas pockets during planning was also assessed. All point dose measurements agreed within 2.7% of the calculated dose, with one exception: a scenario simulating gas present in the planning CT, not overridden during planning, and dissipating at treatment. Relative film measurements passed gamma analysis (3%/3 mm criteria) for all scenarios. Our process validated the Ethos dose calculation for online adapted treatment plans. Based on our results, we made several recommendations for our clinical adaptive workflow. This commissioning process used commonly available equipment and, therefore, can be applied in other clinics for their respective online adaptive platforms
Gold Nanoparticle Monolayers with Tunable Optical and Electrical Properties
No full textCentimeter-scale gold nanoparticle
(Au NP) monolayer films have
been fabricated using a water/organic solvent self-assembly strategy.
A recently developed approach, drain to deposit, is demonstrated to
be most effective in transferring the Au NP films from the water/organic
solvent interface to various solid substrates while maintaining their
integrity. The interparticle spacing was tuned from 1.4 to 3.1 nm
using alkylamine ligands of different lengths. The ordering of the
films increased with increasing ligand length. The surface plasmon
resonance and the in-plane electrical conductivity of the Au NP films
both exhibit an exponential dependence on the interparticle spacing.
These findings show great potential in scaling up the manufacturing
of high-performance optical and electronic devices based on two-dimensional
metallic nanoparticle superlattices
Primary central nervous system post-transplant lymphoproliferative disorders: the spectrum of imaging appearances and differential
No full textAbstract Objective Central nervous system post-transplant lymphoproliferative disorder (CNS-PTLD) is a rare disease that presents with non-specific signs and symptoms. The purpose of this article is to present the imaging appearances of CNS-PTLD by magnetic resonance imaging. We highlight the differential diagnostic considerations including primary central nervous system lymphoma, glioblastoma, cerebral abscess, and metastatic disease. This is an important topic to review since in daily practice the diagnosis of CNS-PTLD is often not initially considered when present due to its rarity and the lack of radiologists’ familiarity with the disease. Conclusion Knowing the unique imaging features of CNS-PTLD narrows the differential diagnosis, facilitates the diagnostic work-up, and optimizes making the diagnosis. Advanced MRI data for CNS PTLD is limited but is promising for helping with narrowing the differential diagnosis
