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Exploring LED Efficiency at BNL's CFN

Kim Kisslinger

CFN's Kim Kisslinger, seen here with a focused-ion beam instrument, reduced the InGaN samples to a thickness of just 20 nanometers to prepare them for electron microscopy.

From the high-resolution glow of flat screen televisions to light bulbs that last for years, light-emitting diodes (LEDs) continue to transform technology. The celebrated efficiency and versatility of LEDs and other solid-state technologies including laser diodes and solar photovoltaics make them increasingly popular. Their full potential, however, remains untapped, in part because the semiconductor alloys that make these devices work continue to puzzle scientists.

A contentious controversy has surrounded the high intensity of one leading LED semiconductor – indium gallium nitride (InGaN) – with experts split on how the material is able to provide the LED’s remarkable efficiency. Using state-of-the-art instruments at the Center for Functional Nanomaterials (CFN), researchers recently established a foolproof method for investigating InGaN materials. These non-destructive imaging techniques can now be used to help unlock the secrets of this amazing alloy.

The InGaN alloy is of extreme interest to scientists and inventors in the semiconductor and solid-state lighting fields. It has the ability to emit light over a wide range of wavelengths – manifesting as different colors simply by changing the relative amounts of indium and gallium in the material. Scientists are exploring the fundamentals of light emission in this material, as well as pushing the frontiers of the exciting field of excitonics, where light and electrons interact both to store energy and mediate its transfer in a wide range of materials. A deeper understanding of excitonics could impact many real-world devices including: blue and green LEDs, ultra-high-efficiency solar photovoltaics, laser pointers and Blu-ray writers, and ultraviolet LEDs for medical and industrial applications.

To learn more about this exciting research read the full article.

2013-4164  |  INT/EXT  |  Media & Communications Office

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