Artificial Eye (04.28.05) - A camera that transmits pictures into the brain is giving some people suffering from blindness the chance at partial eyesight again.
Liver On A Chip (02.24.05) - Developing the right drugs to treat liver disease has been a struggle for researchers, but a nanotechnologist is changing that.
Scientists have found a way to change electronics that could eventually make the parts inside your television, computer or cell phone even smaller. As this ScienCentral News video explains, scientists have found — in principle at least — a way to shrink parts of them down to the size of a single molecule.
Shrinking Electronics
Researchers working at the University of Alberta have shown that it is possible to create an electronic switching device the size of a single molecule. Similar to the transistors and integrated circuits inside almost all of today's electronic devices, the nano-transistor is, according to designer Robert Wolkow, "Perhaps a hundred or a thousand times smaller than a conventional transistor, but, more importantly, it uses perhaps a million times less power than a conventional transistor."
Wolkow is a physics professor at the University of Alberta and leader of the molecular-scale devices group at Canada's National Institute of Nanotechnology. His report on the nano-transistor appeared in the journal Nature.
Transistors are electronic switching devices where a small amount of electricity is used like a gate to control the flow of larger amounts of electricity. Today's transistors need about a million electrons to control the flow, but Wolkow's transistor needs only one electron to control electrical flow through a molecule. Wolkow says that should make his device much faster, explaining, "Imagine you're filling up a bucket with water. If you have a given flow from the garden hose, it clearly takes longer to fill a big bucket than a little thimble, and we have a little thimble that only needs one electron."
A researcher works in Wolkow's lab.
To make the device, Wolkow and his team had to find a way to get a molecule to bond with a silicon surface. "A trick we've developed allows us to more or less point at a particular atom, a particular spot on the [silicon's] surface and cause that molecule to attach right there. The molecule then reaches over and plucks an adjacent hydrogen atom off the surface, thereby creating this special surface site, this special silicon atom that can be charged. And it's that chargeable atom that allows us to gate or regulate the current through that molecule."
A second challenge was to make three connections to just one molecule. Transistors have three connections. The first is the flow of electrons in, the second is the flow back out and the third is the valve that controls the flow. He described attaching three connections to one molecule as like trying to get three watermelons to all touch a poppy seed at the same time. He says, "What we've done is make two connections, two watermelons if you like, act like three."
Vacuum tubes like this are now museum pieces.
Originally, vacuum tubes, were used to control electricity. They dominated the electronics industry until the 1960's. The solid-state transistor replaced the tube ushering in an era of smaller-cheaper electronics that gave off less heat and could often run on batteries. Eventually they were ganged together into integrated circuit "chips" that help run many things, including computers, televisions, cell-phones and even your car.
Scientists have been able to tweak the design of the original silicon chips, squeezing more and more transistors on increasingly powerful and faster chips. But, as Wolkow explains, "There are fundamental limits that say we cannot go further. Beyond about ten years from now things will be static. There won't be anything left you can do to tweak or advanced a silicon-based technology."
Because of that, scientists worldwide have been looking for ways to develop molecular electronics, which offers the potential of cheaper and faster electronic devices that use less power and give off less heat.
This research is only a first step. Wolkow says, "I've tried to stress all along that this is a highly impractical device today. It's a proof of concept and it's not ready to use." He explains that "We can switch this device on and off on a scale of, perhaps, minutes," while a computer needs to switch several times a second. So his device will have to be sped up. But, Wolkow adds, "In principle, there's nothing preventing us from doing that."
This research appeared in the June 2, 2005 issue of Nature and was funded by ICORE, the National Research Council, Science and Engineering Research Canada, the Canada Foundation for Innovation, the University of Alberta and the Canadian Institute for Advanced Research.
delicious
digg
magnolia
reddit
newsvine
netscape
netvibes
