General Info

Contact Information:

   Voice (505) 844-7092

   Fax   (505) 844-4045

   Cell   (505) 480-4267

   Email: jytsao@sandia.gov

Brief Bio

Jeff is currently a Distinguished Member of Technical Staff at Sandia National Laboratories, and Chief Scientist of its Energy Frontier Research Center for Solid-State-Lighting Science.  His work involves integrated science, technology and economic modeling in Solid-State Lighting and other areas.  He is also exploring embedded-network models of the evolution of social knowledge – an emerging approach to the field of “evolutionary epistemology.”

During 2000-2001 Jeff served as vice-president of R&D at E2O Communications, Inc., a U.S.-based pre-IPO fiber communications components company.  During 1993-2000, he served as manager of various technical groups at Sandia National Laboratories in the area of compound semiconductor materials and devices.  In 1998, he took a sabbatical at the Institute of Materials Research and Engineering in Singapore, where he developed and gave a comprehensive series of twelve lectures on compound semiconductor epitaxy.

Jeff has authored or co-authored over 147 journal articles, holds 9 U.S. patents, and is author of a 1993 research monograph “Materials Fundamentals of Molecular Beam Epitaxy,” for which he won Martin Marietta’s 1994 Author of the Year and Jefferson Cup awards.  He co-authored an influential 1999 white paper outlining the potential of Solid-State Lighting, and edited the comprehensive 2002 U.S. Solid-State Lighting Roadmap.  He has helped the Office of Basic Energy Science coordinate two recent workshops and reports: one in 2005 on “Basic Research Needs in Solar Energy Utilization,” and another in 2006 on “Basic Research Needs in Solid-State Lighting.”  He recently won an Asian-American Engineer-of-the-Year 2013 Award.

Jeff has been active in various professional societies, including the Materials Research Society, for which he has co-chaired two symposia, was general co-chair of the Spring 1995 meeting, served for several years on the program committee, and during 1998-2000 coordinated the graduate student awards.  He was elected Fellow of the American Physical Society in 1996, and Fellow of the American Association for the Advancement of Science in 2008.

Full C.V. (June 2014)

 

 

 

SCIENCE OF SCIENCE AND COMPLEX ADAPTIVE SYSTEMS

Art and Science of Science and Technology: Proceedings of the Forum and Roundtable

(Sandia National Laboratories, Albuquerque, NM, June 5-7,2013; J.Y. Tsao, G. R. Emmanuel, T. Odumosu, A.R. Silva, V. Narayanamurti, G.J. Feist, G.W. Crabtree, C.M. Johnson, J.I. Lane, L. McNamara, S.T. Picraux, R.K. Sawyer, R.P. Schneider, C.D. Schunn and R. Sun; Science, Technology and Public Policy Program, Belfer Center for Science and International Affairs, Harvard Kennedy School, December, 2013.

The purpose of this Forum and Roundtable was to initiate a dialog between the two communities: distinguished practitioners of the art of research and experts in the emerging science of research. The Forum and Roundtable was held at Sandia National Laboratories with a dual focus: to identify science that can be applied to improving how research is done and to identify ways in which Sandia could apply such to its own processes.

Engineering the Ultimate Dynamical Social System: what we know and don’t know about how scientists do science

(Jeff Tsao)

  Talk given at Complex 2012 (Santa Fe, 2012) (SAND 2012-10354C).

In this talk, we discuss how the system of science is a complex adaptive system and how it might be analyzable within a framework of a co-evolving dual network of people and ideas.

A Case for Sandia Investment in Complex Adaptive Systems Science and Technology

(Curtis M. Johnson, George A. Backus, Theresa J. Brown, Richard Colbaugh, Katherine A. Jones, Jeffrey Y. Tsao) (SAND 2011-9347P and SAND 2012-3320) (October 2011)

In this white paper, we make a case for Sandia National Laboratories investments in complex adaptive systems science and technology (S&T) -- investments that could enable higher-value-added and more-robustly-engineered solutions to challenges of importance to Sandia’s national security mission and to the nation.

A Brief History of Sandia National Laboratories and the Department of Energy’s Office of Science: Interplay between Science, Technology, and Mission

(Jeff Tsao, Jerry Simmons, Sam Collis, Andy McIlroy, Sam Myers, Tom Picraux, Fred Vook) (SAND 2011-5462) (October 2011)

In this report, we review the history of Sandia’s fundamental science programs supported by the Office of Science.  We present: (a) a technical and budgetary snapshot of Sandia’s current programs supported by the various sub-offices within DOE-SC; (b) statistics of highly-cited articles supported by DOE-SC; (c) four case studies (ion-solid interactions, combustion science, compound semiconductors, advanced computing) with an emphasis on mutually beneficial interactions between science, technology, and mission; and (d) appendices with key memos and reminiscences related to fundamental science at Sandia.

Kuhn, Galileo, Casimir: Insights into the relationship between Science and Technology

(Jeff Tsao) (SAND 2013-7804 P) (June 2011)

This presentation was given at a strategic planning discussion meeting at Sandia, and discusses bi-translational S&T, something that might be called a virtuous “Casimir’s Spiral,” in which science leads to new technology, while technology leads to new science.

Galileo’s Stream: A Framework for Understanding Knowledge Production (Jeff Tsao, Kevin Boyack, Mike Coltrin, Jessica Turnley, Wil Gauster) (SAND 2006-7622J) (Research Policy 37, 330-352) (March 2008)

This paper introduces a new framework for understanding knowledge production in which:  knowledge is produced in stages (along a research to development continuum) and in three discrete categories (science and understanding, tools and technology, and societal use and behavior); and knowledge in the various stages and categories is produced both non-interactively and interactively.

Consumer Preferences and Funding Priorities in Scientific Research (Jeff Tsao) (Science and Public Policy 16, 294-298) (October 1989)

This paper discusses the possibilities for a de-centralized market-oriented system for funding scientific research, in which researchers receive a form of royalty for the use of their published papers.

energy

Solid-State Lighting: An Energy Economics Perspective (Jeff Tsao, Harry Saunders, Randy Creighton, Mike Coltrin, Jerry Simmons) (SAND 2010-1559 J) (Journal of Physics D 43, 354001 (2010))

In this paper, we provide estimates of the potentially massive shifts due to solid-state lighting of (a) the consumption of light, (b) the human productivity and energy use associated with that consumption, and (c) the semiconductor chip area inventory and turnover required to support that consumption.  For past behavior, we use recent studies of historical and contemporary consumption patterns analyzed within a simple energy-economics framework (a Cobb-Douglas production function and profit maximization).  For extrapolations into the future, we use recent reviews of believed-achievable long-term performance targets for solid-state lighting.  We also discuss ways in which the actual magnitudes could differ from the baseline magnitudes of these shifts.  These include: changes in human societal demand for light; possible demand for features beyond lumens; and guidelines and regulations aimed at economizing on consumption of light and associated energy.

The World’s Appetite for Light:  Empirical Data and Trends Spanning Three Centuries and Six Continents (Jeff Tsao, Paul Waide) (SAND 2008-4246J) (LEUKOS 6, 259-281) (Apr 2010)

In this paper, we collected and self-consistently analyzed data for per-capita consumption of artificial light, per-capita gross domestic product, and ownership cost of light.  The data span a wide range (three centuries, six continents, five lighting technologies, and five orders of magnitude), and are consistent with a linear variation of per-capita consumption of light with the ratio between per-capita gross domestic product and ownership cost of light.  No empirical evidence is found for a saturation in per-capita consumption of light, even in contemporary developed nations.  Finally, we extrapolate to the world in 2005, and find that 0.72% ($437B/yr) of world gross domestic product and 6.5% (29.5 Quads/yr) of world primary energy was used to produce 130 Plmh/yr of artificial light.

The Rebound Effect: An Analysis of the Empirical Data for Lighting (Jeff Tsao, Paul Waide, Harry Saunders) (Dec 2008) (SAND 2008-7959C) with notes

This talk was given at the 28th USAEE/IAEE North American Conference in New Orleans.

Some Simple Physics of Global Warming (Jeff Tsao) (March 2008) (SAND 2008-2255P) and notes

These viewgraphs are based on a tutorial lecture given for a high school physics class at the Bosque School in Albuquerque.

Basic Research Needs in Solid-State Lighting (Julie Phillips, Paul Burrows, Chairs) (October 2006)

This report is based on a U.S. Department of Energy Office of Basic Energy Science’s Workshop on Solid-State Lighting (SSL), May 22–24, 2006, chaired by Julie Phillips and Paul Burrows.  It examines the gap separating current state-of-the-art SSL technology from an energy efficient, high-quality, and economical SSL technology suitable for general illumination; and identifies the most significant fundamental scientific challenges and research directions that would enable that gap to be bridged.

Solar FAQs (Jeff Tsao, Nate Lewis, George Crabtree) (SAND 2006-2818P) and related informal talk (SAND 2006-2821P) (April 2006)

This white paper asks and answers a series of questions regarding the potential of the sun to supply energy to the world.  The questions are drawn in large part from the U.S. Department of Energy Office of Basic Energy Science’s recent report on Basic Research Needs in Solar Energy Utilization.  The answers are given in a format suitable for a lay technical audience, and are supplemented by detailed calculations and comprehensive references.

Basic Research Needs in Solar Energy Utilization (Nate Lewis, George Crabtree, Chairs) (October 2005)

This report is based on a U.S. Department of Energy Office of Basic Energy Science’s Workshop on Solar Energy Utilization, April 18–21, 2005, chaired by Nate Lewis and George Crabtree.  It examines the challenges and opportunities for the development of solar energy as a competitive energy source and identifies the technical barriers to large-scale implementation of solar energy and the basic research directions showing promise to overcome them.

semiconductor materials and devices

The World of Compound Semiconductors

This is a book started in 2002, worked on for about a year, then abandoned.  Its intent was to have been to provide an integrated guide to the science, technology and applications of the compound III-V semiconductors.  Its unique aspect was to have been its emphasis and organization around an objective database (linked file is in procite format) of the most highly-cited journal articles and U.S. patents in the field.  Comments and avenues for its continuation are most welcome.

Optically-pumped long-wavelength vertical-cavity surface-emitting laser with high modulation bandwidth (MV Ramana Murty, D Xu, CC Lin, CL Shieh, JY Tsao, J Cheng, Appl Phys Lett 86, 061108, 2006)

Electrically pumped long-wavelength VCSEL with air gap DBR and methods of fabrication (CL Shieh, JY Tsao, US Patent 6,696,308, February 24 2004)

Segmented-mirror VCSEL (JY Tsao, CL Shieh, PD Dapkus, J Yang, US Patent 6,594,294, July 15 2003)

Semiconductor Epitaxy: Science, Technology and Applications 40MB (July-November 1998) (SAND 2007-1800P)

This series of twelve lectures was given over four months at the Institute of Materials and Engineering (IMRE) in Singapore.  The series began with an overview of materials and device families and properties, and of epitaxy growth techniques such as molecular beam epitaxy (MBE) and chemical-vapor deposition (CVD).  Then, the science of epitaxy was discussed, including vapor, surface, thin film and bulk phenomena.  Finally, the series ended with an overview of the technology and applications of epitaxy, with attention to particular III/V alloy systems as well as to manufacturing issues.

Materials Fundamentals of Molecular Beam Epitaxy (Academic Press, 1993) and figures (SAND 2007-1801P)

This book gathers together the basic materials science principles that apply to MBE, and treats in great depth its most important aspects. Throughout, it makes use of thermodynamic and statistical calculations based on intuitive and physically motivated semi-empirical models.

Solid-State Lighting

Solid-State Lighting: Toward Smart and Ultra-Efficient Materials, Devices, Lamps and Systems

(Mary Crawford, Jon Wierer, Art Fischer, George Wang, Dan Koleske, Ganesh Subramania, Mike Coltrin, Jeff Tsao) Chapter to be published in D.L. Andrews, Ed., “Photonics Volume 3: Photonics Technology and Instrumentation” (Wiley, 2013)

   Solid-state lighting has made tremendous progress over the past decade, with the potential to make much more progress over the coming decade.  In this chapter, we review the current status of solid-state lighting  relative to its ultimate potential to be “smart” and ultra-efficient. Smart, ultra-efficient solid-state lighting would enable both very high “effective” efficiencies (as defined in subsection 2.3), as well as potentially large increases in human productivity.  To achieve ultra-efficiency, phosphors must eventually give way to multi-color semiconductor electroluminescence; we review some of the technological challenges associated with such electroluminescence at the semiconductor level.  To achieve smartness, additional characteristics such as the ability to control light flux and spectra in time and space will be important; we review some of the technological challenges associated with achieving these characteristics at the lamp level, as well as some of the potential future system applications that such smartness might enable.

Comparison between blue lasers and light-emitting diodes for future solid-state lighting

(Jon Wierer, Jeff Tsao, Dmitry Sizov) Laser & Photonics Reviews (August, 2013).

   Solid-state lighting (SSL) is now the most efficient source of high color quality white light ever created. Nevertheless, the blue InGaN light-emitting diodes (LEDs) that are the light engine of SSL still have significant performance limitations. Foremost among these is the decrease in efficiency at high input current densities widely known as “efficiency droop.” Efficiency droop limits input power densities, contrary to the desire to produce more photons per unit LED chip area and to make SSL more affordable. Pending a solution to efficiency droop, an alternative device could be a blue laser diode (LD). LDs, operated in stimulated emission, can have high efficiencies at much higher input power densities than LEDs can. In this article, LEDs and LDs for future SSL are explored by comparing: their current state-of-the-art input-power-density-dependent power conversion efficiencies; potential improvements both in their peak power-conversion efficiencies and in the input power densities at which those efficiencies peak; and their economics for practical SSL.

Four-color laser white illuminant demonstrating high color-rendering quality

(Sasha Neumann, Jon Wierer, Wendy Davis, Yoshi Ohno, Steve Brueck, Jeff Tsao) Optics Express 19, A982-990 (2011) SAND2011-2743J.

   Solid-state lighting is currently based on light-emitting diodes (LEDs) and phosphors.  Solid-state lighting based on lasers would offer significant advantages including high potential efficiencies at high current densities. Light emitted from lasers, however, has a much narrower spectral linewidth than light emitted from LEDs or phosphors.  Therefore it is a common belief that white light produced by a set of lasers of different colors would not be of high enough quality for general illumination. We tested this belief experimentally, and found the opposite to be true. This result paves the way for the use of lasers in solid-state lighting.

Solid-state lighting: ‘The case’ 10 years after and future prospects (Roland Haitz, Jeff Tsao) Physica Status Solidi A 208, 17-29 (2011).

   Ten years ago, a white paper titled “The Case for a National Research Program on Semiconductor Lighting” outlined the promise and potential of semiconductor light-emitting diodes (LEDs) for general illumination.  Since then, investments in the now-renamed field of solid-state lighting (SSL) have accelerated and considerable progress has been made, not always in the directions envisioned at the time.  In this paper, two of the original four authors comment on the white paper’s hits and misses, while making the original white paper available archivally as supplemental online material.  Finally, we make new predictions for the coming 10-20 years.

Solid-State Lighting: An Integrated Human Factors, Technology and Economic Perspective (Jeff Tsao, Mike Coltrin, Mary Crawford, Jerry Simmons) (July 2010) (SAND 2009-5551J) (Proceedings of the IEEE 98, 1162-1179)

In this article, we present a high-level overview of solid-state lighting, with an emphasis on white lighting suitable for general illumination.  We characterize in detail solid-state lighting’s past and potential-future evolution using various performance and cost metrics, with special attention paid to inter-relationships between these metrics imposed by human factors, technology and economic considerations.

Solid-State Lighting: The III-V Epi “Killer App”  (Jeff Tsao) (May 2010) (SAND 2010-4049C) and video

This talk was given at the International Conference on Metal-organic Vapor Phase Epitaxy (ICMOVPE) May 24 2010 in Lake Tahoe, NV.

The Next Semiconductor Revolution: This Time It’s Lighting! (Jeff Tsao) (Mar 2010) (SAND 2010-1957P) and video

This tutorial talk for students and the general public was given at the Albuquerque Academy March 31 2010 in Albuquerque NM.

(Lighting and) Solid-State Lighting: Science, Technology, Economic Perspectives (Jeff Tsao) (Jan 2010) (SAND 2010-1090C) and video

This talk was given at Photonics West Jan 26 2010 in San Francisco, CA.

Research challenges to ultra-efficient inorganic solid-state lighting (Julie Phillips, Mike Coltrin, Mary Craford, Art Fischer, Mike Krames, Regina Mueller-Mach, Gerd Mueller, Yoshi Ohno, Lauren Rohwer, Jerry Simmons, Jeff Tsao) (SAND 2007-5470J) and figures (Laser and Photonics Reviews 1, 307-333 (November 2007)

This review article discusses approaches to inorganic solid-state lighting that could conceivably achieve ultra-high (70% or greater) efficiency, and the significant research questions and challenges that would need to be addressed if one or more of these approaches were to be realized.

A recursive process for mapping and clustering technology literatures: case study in solid-state lighting (Kevin Boyack, Jeff Tsao, Ann Miksovic, Mark Huey) (SAND2008-4564) and figures (2009)

This report analyzes a comprehensive dataset of English-language articles and U.S. patents published or issued in the knowledge domain of electroluminescent materials and phenomena.  A number of analyses were performed, including:  identification of knowledge sub-domains of historical and recent importance, and trends over time of the contributions of various nations and continents to the knowledge domain and its sub-domains.

Solid-State Lighting: a Case Study in Science and Technology Evolution (Jeff Tsao) (July 2006) (SAND 2006-4047A)

This talk was given at the 2006 China International Forum on Solid-State Lighting (CIFSSL) in Shenzhen, China.

Technology Footprinting and Solid-State Lighting (Jeff Tsao, Kevin Boyack, Mark Huey, Ann Miksovic, June 2006) (SAND 2006-7621P)

This work was sponsored by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Building Technologies Program.  This set of viewgraphs explores the development of a tool that might be called “technology footprinting,” and the preliminary application of that tool to solid-state lighting.

Solid-State Lighting: the Potential and the Challenges (Jeff Tsao) (August 11-12 2005) (SAND 2005-4894A)

These two lectures were given in two half-days at the Institute of Materials Research and Engineering (IMRE) in Singapore.

Evolution of Solid-State Lighting: Market Pull and Technology Push (Jeff Tsao) (April 2005) (SAND 2008-2251C) and notes

This talk was given at the 2005 China International Forum on Solid-State Lighting (CIFSSL) in Xiamen, China.

Solid-State Lighting: Lamps, Chips and Materials for Tomorrow (Jeff Tsao) (IEEE Circuits and Devices Magazine Vol 20 Issue 3 pp 28-37, May-June 2004) (SAND 2003-3018J)

The aims of this article were twofold.  First, a brief overview of conventional and SSL lighting technologies was given.  Second, a description was given of some of the simplest but most important lamp, chip, and materials design choices that would need to be made if SSL technology is to fulfill its promise for general illumination.

Final Report on Grand Challenge LDRD Project:  A Revolution in Lighting -- Building the Science and Technology Base for Ultra-Efficient Solid-State Lighting (SAND 2004-2365, May 2004)

This SAND report was the final report on Sandia’s Grand Challenge LDRD SSL Project   This project is considered one of Sandia’s most successful GCLDRDs.  This report reviews not only technical highlights, but also the genesis of the idea for SSL, the initiation of the SSL GCLDRD, and the goals, scope, success metrics, and evolution of the SSL GCLDRD over the course of its life.

Solid-State Lighting: Roadmap (Jeff Tsao) (Laser Focus World Vol 39 Issue 5 pp S11-S14, May 2003) (SAND 2003-0556J)

A summary of the 2002 SSL roadmap, with a special emphasis on energy savings projections.

Light Emitting Diodes (LEDs) for General Illumination (Jeff Tsao, Ed.) (November 2002) (SAND 2002-3408P)

This report was the first comprehensive SSL technology roadmap, and provided quantitative enumeration of key technology targets, prioritization of research challenges, and key decisions related to competing approaches.  It also discussed lighting systems issues necessary to achieve mass penetration of LEDs in the marketplace.

Solid-State Lighting: Illumination through Semiconductor Science Website

A website, actively maintained from December 2001 through September 2006, whose intent was “to gather together information relevant to solid-state lighting, and to help stimulate the development of the science and technology foundation necessary to enable the promise and potential of solid-state lighting.”

The Case for a National Research Program on Semiconductor Lighting (Roland Haitz, Fred Kish, Jeff Tsao, Jeff Nelson, July 2000) (SAND 2000-1612)

This white paper was the first to discuss the vast technological and energy-savings potential of solid-state lighting technology.

 

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