August 9, 2013
Is Humble Table Salt The Savior Of The Tech Industry?
Brett Smith for redOrbit.com - Your Universe Online
Silicon nanostructures are used in everything from electronics to energy storage, but their production process is complex and costly. However, engineers from Oregon State University have identified a compound sitting in every kitchen that could reduce production costs and boost mass production of the tiny structures: table salt.
According to a recently published report in the journal Scientific Reports, sodium chloride can melt and absorb heat at a crucial step during the “magnesiothermic reaction” used to create the nanostructures, by essentially keeping the nanostructures from collapsing. After the reaction is complete, the liquid salt can be washed away with water and used again.
The study authors said the groundbreaking discovery could open doors to new, cheaper commercial processes for creating the structures that can be used in a wide range of technology.
“This could be what it takes to open up an important new industry,” said co-author David Xiulei Ji, an assistant professor of chemistry at OSU. “There are methods now to create silicon nanostructures, but they are very costly and can only produce tiny amounts.”
The team was able to successfully develop a method that involves the mixing of sodium chloride and magnesium with diatomaceous earth, a cheap and readily obtainable form of silicon. When the reaction process hits around 1,500 degrees F, the salt melts and absorbs heat, keeping the nanostructure from collapsing without contaminating the process as a whole.
The study authors noted that their method could be easily scaled up for commercial production.
“The use of salt as a heat scavenger in this process should allow the production of high-quality silicon nanostructures in large quantities at low cost,” Ji said. “If we can get the cost low enough many new applications may emerge.”
The nanostructures, which are not visible to the naked eye, could increase technical capabilities much further than the first few waves of silicon-based technology. The tiny structures could eventually be used in biological imaging, electronic sensors, materials capable of converting heat into electricity, and energy storage.
The research team said batteries are one of the most obvious applications to emerge from the technology. Ji said silicon nanostructures could be used to create a wide range of rechargeable batteries that last nearly twice as long as conventional batteries.
The process was also used to create nanoporous composite materials made from silicon and germanium. These materials can be used in semiconductors, thermoelectric materials and electrochemical energy devices.
Silicon-based electronics emerged in the late 1950s in the form of integrated circuits, also referred to as microchips. The earliest microchips included only a few transistors each – a far cry from today’s chips that hold billions of electrical elements on a single chip. Increased chip capacity has led to greater processing power and the formulation of Moore’s Law – which says the number of transistors in an integrated circuit doubles approximately every two years.
As construction processes allows for smaller and smaller components to be placed on each microchip, engineers are quickly approaching certain natural barriers of physics and thermodynamics. Experts say new methods may have to be developed soon to expand the current commercial capabilities