Briefs 2008


Editors Additional complimentary copies are available by contacting: Cover Page: The figure depicts the result of a theoretical calculation of electrons moving through a high mobility two-dimensional (2D) electron layer with a superimposed 2D periodic (superlattice) potential, subject to an in-plane DC electric field. The height shows the number of electrons. The oscillatory behavior in time shows that electrons pass entirely through the Brillouin zone before scattering, hence executing a " back and forth " AC motion in real space, due to a simple DC field. The Physical, Chemical, and Nano Sciences Center creates new scientific knowledge in support of Sandia's mission areas – nuclear weapons; energy, resources, and nonproliferation; defense systems and assessments; and homeland security and defense. We provide science-based solutions in support of Sandia's broad national security mission. We also perform focused long-term research in areas likely to have impact on future Sandia missions and national security, particularly in the physical, chemical, and nano sciences. This volume highlights representative research in our areas of emphasis, including Science for Sandia's National Security Mission [including the Qualification Alternatives to the Sandia Pulsed Reactor (QASPR) Program]; GaN and Related Materials; Nanoscience and Nanotechnology; and a sampling of some of our most fundamental scientific studies. The activities of the Physical, Chemical, and Nano Sciences Center are supported by a diverse set of funding sources reflecting the broad impact of our work, both scientifically and programmatically. The research described in this volume illustrates the importance of a strong science base in the physical, chemical, and nano sciences for the success of the Department of Energy's missions and Sandia's broader mission in national security. In this work, we have benefited immeasurably from our partnerships with colleagues across the labs, in universities, and in industry. We gratefully acknowledge their collaboration. We appreciate your interest in our work and welcome your comments and inquiries. Motivation—The QASPR program is developing means to certify electronic systems for intense bursts of MeV neutrons without the Sandia Pulsed Reactor (SPR), decommissioned in Sept. 2006. Testing in available irradiation facilities will be combined with new, science-based modeling to predict time-dependent device and circuit performance under inaccessible conditions. A central concern is carrier recombination at neutron damage in Si bipolar-junction transistors (BJTs). Gains may be reduced from > 100 to < 1, and rapid damage evolution causes this reduction to vary greatly over times from microseconds to seconds. The PCNSC has …

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@inproceedings{Phillips2008Briefs2, title={Briefs 2008}, author={Julia M. Phillips and David R. Sandison and Jerry A. Simmons and Katelynn G. Florentino}, year={2008} }