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Carrier dynamics model for laser-solid interactions

Chow, Weng W.; Moore, Christopher H.; Biedermann, Laura B.; Hopkins, Matthew M.; Dagel, Daryl D.; Cartwright, Keith C.

This report describes a model for the time development of carrier distributions within a metallic or semiconductor target after the onset of an incident laser pulse. The dynamics of electron and hole populations in momentum-resolved conduction- and valence-band states are treated at the level of carrier-carrier and carrier-phonon scattering. These scattering events result in plasma and lattice heating, which in turn lead to electron thermionic emission and tunneling, and target material ablation. A fairly phenomenological approach is taken to mitigate numerical computation demands, in order to facilitate parametric studies. Two examples of application are presented. One involve s the incident of an intense near-infrared laser pulse on a solid aluminum target, where the goal is to connect excited species emission to physics at a band-structure level. The second involves modeling the trigger mechanism in laser-triggered high-voltage switches, where the results are used as input to highly intensive particle-in-cell (PIC) plasma simulations of switch operation.

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TYPE SAND Report YEAR 2017
DOIOSTI

DESALINATION AND WATER TREATMENT RESEARCH AT SANDIA NATIONAL LABORATORIES

Rigali, Mark J.; Miller, James E.; Altman, Susan J.; Biedermann, Laura B.; Brady, Patrick V.; Kuzio, Stephanie P.; Nenoff, T.M.; Rempe, Susan R.

Water is the backbone of our economy - safe and adequate supplies of water are vital for agriculture, industry, recreation, and human consumption. While our supply of water today is largely safe and adequate, we as a nation face increasing water supply challenges in the form of extended droughts, demand growth due to population increase, more stringent health-based regulation, and competing demands from a variety of users. To meet these challenges in the coming decades, water treatment technologies, including desalination, will contribute substantially to ensuring a safe, sustainable, affordable, and adequate water supply for the United States. This overview documents Sandia National Laboratories' (SNL, or Sandia) Water Treatment Program which focused on the development and demonstration of advanced water purification technologies as part of the larger Sandia Water Initiative. Projects under the Water Treatment Program include: (1) the development of desalination research roadmaps (2) our efforts to accelerate the commercialization of new desalination and water treatment technologies (known as the 'Jump-Start Program),' (3) long range (high risk, early stage) desalination research (known as the 'Long Range Research Program'), (4) treatment research projects under the Joint Water Reuse & Desalination Task Force, (5) the Arsenic Water Technology Partnership Program, (6) water treatment projects funded under the New Mexico Small Business Administration, (7) water treatment projects for the National Energy Technology Laboratory (NETL) and the National Renewable Energy Laboratory (NREL), (8) Sandia- developed contaminant-selective treatment technologies, and finally (9) current Laboratory Directed Research and Development (LDRD) funded desalination projects.

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TYPE SAND Report YEAR 2016
DOIOSTI

Laser Direct Write Synthesis of Lead Halide Perovskites

Journal of Physical Chemistry Letters

Kaehr, Bryan J.; Chou, Stanley S.; Swartzentruber, Brian S.; Biedermann, Laura B.; Carter, Clive B.; Meyer, Kristin M.; Burckel, David B.

Lead halide perovskites are increasingly considered for applications beyond photovoltaics, for example, light emission and detection, where an ability to pattern and prototype microscale geometries can facilitate the incorporation of this class of materials into devices. Here we demonstrate laser direct write of lead halide perovskites, a remarkably simple procedure that takes advantage of the inverse dependence between perovskite solubility and temperature by using a laser to induce localized heating of an absorbing substrate. We demonstrate arbitrary pattern formation of crystalline CH3NH3PbBr3 on a range of substrates and fabricate and characterize a microscale photodetector using this approach. This direct write methodology provides a path forward for the prototyping and production of perovskite-based devices.

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TYPE Journal Article YEAR 2016
DOIOSTIScopus

Creating Fantastic PI Workshops

Perkins, David N.; Biedermann, Laura B.; Clark, Blythe C.; Thayer, Rachel C.; Dagel, Amber L.; Gupta, Vipin P.; Hibbs, Michael R.; West, Roger D.

The goal of this SAND report is to provide guidance for other groups hosting workshops and peerto-peer learning events at Sandia. Thus this SAND report provides detail about our team structure, how we brainstormed workshop topics and developed the workshop structure. A Workshop “Nuts and Bolts” section provides our timeline and check-list for workshop activities. The survey section provides examples of the questions we asked and how we adapted the workshop in response to the feedback.

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TYPE SAND Report YEAR 2015
DOIOSTI
Results 26–50 of 86
Results 26–50 of 86