New Semiconductor to Help Power Spacecraft
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New Semiconductor to Help Power Spacecraft

Researchers at the University of Arkansas in the USA are currently developing a new type of semiconductor that could be used to create more efficient photovoltaic solar cells to be used on space missions. Thanks to a $750,000 grant from NASA, the US space agency, they will be able to improve the existing solar energy technology being used on the International Space Station and Hubble telescope to help NASA achieve its 15-year goal of reaching 45% efficiency in solar power.  Better radiation tolerance and lower manufacturing costs are further benefits of this new material. Other space agencies are also experimenting with new ways of harnessing solar power for space exploration missions.

What does this new semiconductor do?

The new photovoltaic devices are being made using a semiconductor comprised of silicon-germanium-tin (SiGeSn), which can source, detect and control light.  The devices work by using a semiconducting material, which creates a photoelectric effect – metals emit electrons when light shines on them – after which an electrochemical process takes place, where crystallised atoms are ironised in a series, which generates an electrical current. Most solar panels work in this way but the new SiGeSn does so more efficiently than the current semiconductors being used.

How is the new semicondutor made?

Creating the silicon-germanium-tin involves an ultra-high-vacuum chemical vapour disposition process on a silicon substrate. To do this, the substrate is exposed to a precursor – a compound that participates in a chemical reaction to create another compound – that reacts on the substrate, leaving behind the desired deposit.

Other ways solar energy is powering space missions

Using solar power for space exploration is not a new phenomenon but it is a technology that is continuously being explored in new ways. Not only are new materials being created, such as silicon-germanium-tin, but they are being deployed in new ways too. The Japan Aerospace Exploration Agency launched the IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) spacecraft in 2010 using a 20-metre solar power sail to power its flight. At only 0.0003 inches thick, the sail is incredibly thin and uses a combination of photons striking its surface to push it through space and ultra-thin solar cells to generate electricity.  These cells are made of amorphous silicon (a-Si) which can be spread very thinly on a substrate and generate electricity in a not particularly efficient but highly environmentally-friendly manner as they do not rely on toxic heavy metals.

Both of the above scientific developments into powering space missions through solar power would not be possible without highly controlled ultra-high-vacuum conditions here on Earth. AML manufactures the type of Ion Gauge Controllers that make this innovative research possible. Find out more by calling 01903 884141 or email sales@arunmicro.com.

Photo credit: NASA

New Semiconductor Technology Could Extend Moore's Law

Fifty years ago, Gordon Moore, a co-founder of multinational technology company, Intel, predicted that the number of transistors on a single microchip would double every year. Ten years later he revised this estimate to every two years. This is known as Moore's Law. In 2015, this forecast has remained true but even Moore himself has hypothesised that this rate of expansion cannot continue indefinitely. Other commentators have stated that transistors are now so small that Moore's Law could become untrue very soon. However, recent technological breakthroughs have opened up the possibility that Moore's Law may not just remain true but even be exceeded for many years to come.

Is this the End for Moore's Law?

Microchip manufacturers are constantly endeavouring to make chips more powerful and cheaper to build. This has involved packing an increasing number of transistors on to a single silicone wafer. The primary method of achieving this has been to make the components smaller and smaller. At around 14 nanometres many believe that they have reached the limits of how small they can be. However, Intel told The Economist magazine this year that they believe they can make transistors as small as 5 nanometres, about the width of a cell membrane, in the next ten years, but that would be the limit to how small they could be.  These limitations seem to spell the end for Moore's Law.

Breakthrough Techniques

IT technology company IBM made a breakthrough in 2007 when they increased the number of transistors without making them any smaller. Instead they were brought closer together. Using a power transmitting system called 'silicon via technology' they were able to create 3D chips containing 100 more channels through the wafer, eliminating the need for long metal wires connecting components together and shortening the distance electricity travels by 1000%.

Moving on from the Silicon Wafer

Although the use of 3D wafer construction has considerably increased the shelf life of Moore's Law, it still has limitations over time. The University of Connecticut is currently developing new integrated circuit technology, which could extend it even further. A group called POET Technologies has combined optics with electronics to create a wafer made of gallium arsenide, which they claim will be faster, cheaper and more energy efficient than silicon. The researchers state that, going forward, they will be able to fit all the necessary components on to a single chip without the need to connect chips together. Developments like this make it possible for Moore's Law to remain true far into the future.

AML creates ion gauge controllers, which can be used to measure vacuum levels to ensure the optimum conditions for semiconductor manufacture are maintained.  Contact us today for more details about our products by calling us on 01903 884141 or email via sales@arunmicro.com.