This year’s Nobel Prize in Physics is thankfully not being awarded for the discovery of some esoteric atomic particle but rather for the development of a technology that impacts all our lives. The Royal Swedish Academy of Sciences noted in its announcement that the prize was awarded to 3 scientists who “invented a new energy-efficient and environment-friendly light source – the blue light-emitting diode (LED). In the spirit of Alfred Nobel the Prize rewards an invention of greatest benefit to mankind; using blue LEDs, white light can be created in a new way. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources.” Isamu Akasaki of Meijo University and Nagoya University, Japan; Hiroshi Amano of Nagoya University, Japan; and Shuji Nakamura University of California, Santa Barbara, USA, were awarded the prize for this revolutionary technology.
The element which allowed this technology to be developed deserves our attention because its abundance and scarcity will have a major impact on how these technologies can be further utilized. Blue LEDs were made possible due to a little-known metal called gallium which can be found unassumingly under aluminum in the periodic table and has the unusual property of melting at room temperature. Like aluminum it is not found independently in the earth’s crust but rather bound with an array of other elements such as sulfur and nitrogen. Most of the ore for gallium comes from the mining of aluminum bauxite and zinc deposits. However, unlike aluminum which is among the most abundant metals in the earth’s crust, gallium is intensely scarce. The estimate used for gallium in the earth’s crust is around 16.9 ppm (for comparison, copper is estimated to be around 50 ppm in the earth’s crust and aluminum is around 82,000 ppm).
The current production of gallium is quite small since blue LED technology is just beginning to gain traction at a mass commercial scale and most of the other uses of gallium in semiconductors has potential replacement elements. However, if the full potential of LED technology is to be realized gallium will need be produced at a much larger scale. The good news is that currently we are only extracting around 10% of the available gallium byproduct from bauxite aluminum mining. Yet, as the experience with other technology metals, such as rare-earth lanthanide elements has shown, demand can rise rapidly over a short period of time driven by new products such as smart phones. Thus it is essential for mineral policy analysts to start developing cogent scenarios for gallium availability that takes into account the high energy cost of bauxite extraction as well as opportunities for harnessing gallium from recycled materials. By one estimate in Japan approximately 90 tonnes of gallium was produced via recycling of scrap materials in 2010 and the US Department of Energy estimated gallium recycling capacity at around 42%.
As the Nobel committee has itself recognized in the announcement and advanced material posted on their web site, “the material that enabled the development of blue LED is gallium nitride.” Let us use the prize as an opportunity to further raise awareness about our dependence on minerals for so many emerging technologies and find novel ways of most efficiently harnessing and using these precious materials.