SAND 2013-4298W

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Research Challenge 0: Overarching and spillover research

The “zeroth” scientific research challenge is what we call overarching and spillover research. “Overarching” research is what connects the six main scientific research challenges to SSL technology. SSL technology is itself evolving rapidly, and we devote some effort to understanding this evolution so as to provide guidance for the directions of our inquiry to surmount [...]

By | August 7th, 2013|Comments Off on Research Challenge 0: Overarching and spillover research

Brief History of Solid-State Lighting Technology

Semiconductor electroluminescence was first reported by H.J. Round in 1907, and the first light-emitting diode (LED) was reported by O.V. Losev in 1927. Not until the birth of semiconductor physics in the 1940s and 1950s, however, was scientific development of technologies for light emission possible. For solid-state lighting (SSL), using semiconductor electroluminescence to produce visible [...]

By | June 5th, 2013|Comments Off on Brief History of Solid-State Lighting Technology

Research Challenge 6: Beyond Spontaneous Emission

This research challenge explores radiative processes that go beyond incoherent emission. For example, although LEDs (based on spontaneously emitted incoherent light) are presently thought of as the source of choice for white light generation. However, coherent light sources have many potential benefits, including ultra-high efficiency, narrow linewidths, improved directionality of light, and the potential to [...]

By | February 3rd, 2012|Comments Off on Research Challenge 6: Beyond Spontaneous Emission

Research Challenge 5: Enhanced Spontaneous Emission

Our explorations focus on two nanophotonic approaches for modifying the emission environment: controlling the photonic density of states (photonic crystals) and introducing intense localized electromagnetic fields (surface plasmonics). Both approaches require integration of emitters with dielectric, plasmonic, or photonic crystal cavities, which we accomplish through nanofabrication and epitaxial growth (photonic crystals, fabricated metallic structures), chemical [...]

By | February 3rd, 2012|Comments Off on Research Challenge 5: Enhanced Spontaneous Emission

Research Challenge 4: Defect-Carrier Interactions

This research challenge aims to develop an in-depth understanding of the electrical, optical and structural properties of defects in InGaN materials and heterostructures. With such understanding, routes to circumventing a key contributor to nonradiative carrier recombination might be realized, helping to overcome the blue-efficiency, RYG-gap, and functional-light technology challenges. Measured density of an InGaN [...]

By | February 3rd, 2012|Comments Off on Research Challenge 4: Defect-Carrier Interactions

Research Challenge 1: Nanowires

This research challenge explores the synthesis and properties of GaN/InGaN nanowires as a materials architecture for visible light-emission. If nanowire devices could span the entire visible spectrum, the RYG-gap technology challenges would be overcome. In addition, such full-spectrum emission would enable chromaticity-tunable light, which could also impact so-called smart (or higher functionality) lighting, another technology [...]

By | February 3rd, 2012|Comments Off on Research Challenge 1: Nanowires

Research Challenge 3: Competing Radiative and Nonradiative Processes

This research challenge aims to develop a microscopic understanding of the competing physical processes that determine light-emission efficiency of InGaN materials and heterostructures. With such understanding, new routes to ultra-high light-emission efficiency at all current densities and all across the visible spectrum might be realized, thus overcoming the blue-efficiency and RYG-gap [intlink id="8173" type="page"]technology challenges[/intlink]. [...]

By | February 1st, 2012|Comments Off on Research Challenge 3: Competing Radiative and Nonradiative Processes

Research Challenge 2: Quantum Dots and Phosphors

Phosphor in powder form. (KLuTa2O7: Eu3+) This research challenge is aimed at studying materials architectures suitable for SSL wavelength down-conversion. Particular materials we have focused on in this research challenge are Eu3+-doped phosphors and group II-VI semiconductor quantum dots (QDs). Among the principal criteria for such wavelength down-conversion materials are a high [...]

By | February 1st, 2012|Comments Off on Research Challenge 2: Quantum Dots and Phosphors

Our SSLS EFRC’s Scientific Research Challenges and Publications

The Solid-State Lighting Science (SSLS) Energy Frontier Research Center (EFRC) works to advance the scientific foundation that underlies current and potential-future SSL technology, and to ultimately enable significant advances in the efficiency with which SSL is produced and used. We do this through the seven scientific research challenges:  one is what one might call [...]

By | February 1st, 2012|Comments Off on Our SSLS EFRC’s Scientific Research Challenges and Publications

Solid-State Lighting Technology: Current State of the Art and Grand Challenges

The graphic on the left shows the anatomy of a state-of-the-art white solid-state lamp; and the graphic on the right shows in the black curve the spectral power density of the light that it emits. The lamp is basically a blue LED coated with green and red phosphors. Some of the blue light leaks through [...]

By | February 1st, 2012|Comments Off on Solid-State Lighting Technology: Current State of the Art and Grand Challenges