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 firstname.lastname@example.org.
Photo credit: NASA