Efficiently Producing Quantum Dots

generica1 writes "The Edmonton Journal is reporting on the University of Alberta's National Institute for Nanotechnology's recent invention of a new method to produce quantum dots — what are currently the world's smallest quantum dots, possibly allowing for startling increases in the efficiency of semiconductor-based equipment. 'Roughly speaking, we predict there could be a 1,000-time reduction in power consumption with electronic computers built in this new way,' said Robert Wolkow, a physicist at the University of Alberta and leader of the team behind the breakthrough. Read the article for a description of the wave-like phenomenon employed by Wolkow's team to accomplish a vastly lower power consumption during the transfer of electrons."

Comments

First post!

[Anonymous Coward]

So how long until we can see this in use?

Re:First post!

[Bearhouse]

Because that's not how you're suppose to browse if you're modding - see the FAQ.

Read the original article, not this BS

[jpeaton]

Here's the actual article: http://link.aps.org/doi/10.1103/PhysRevLett.102.046805 . The summary linked is crap : "The quantum dot developed by Wolkow's team is much smaller; less than a nanometre in diameter and containing only one or two particles" It's a silicon atom. How many particles in that? I guess the author was talking about subatomic particles, right?? They also claim that Physical Review Letters, is considered the world's premier physics journal. By whom? It was 12th in the ranking in 2007. Finally, they say "The discovery is a highly anticipated milestone in nanotechnology circles." Uhhh?? I don't think so. As usual, this is self-publicity disguised as news.

Re:Read the original article, not this BS

[durrr]

"Previously developed quantum dots range in size from two to 10 nanometres -- a nanometre is one-billionth of a metre -- and contain groupings of 1,000 or more atoms."

"The quantum dot developed by Wolkow's team is much smaller; less than a nanometre in diameter and containing only one or two particles."

I guess your guess is wrong, because atoms are clearly not subatomic particles.

Re:Read the original article, not this BS

[Geoffrey.landis]

... They also claim that Physical Review Letters, is considered the world's premier physics journal. By whom?

By physicists.

It was 12th in the ranking in 2007....

by whom?

I actually agree with most of what your comments above-- there's more hype than reality in that press release-- but Phys Rev Letters really is the gold standard in peer-reviewed physics publication. If somebody ranks PRL as "12th", this is an indication that this ranking system is broken.

Re:Read the original article, not this BS

[Anonymous Coward]

It's actually interesting. When you're working with atomic clusters of around 30 atoms it is difficult to know the structure since there are sufficient degrees of freedom that calculations are difficult, but the surface effects and quantum confinement effects that prevent the bulk crystallinity from dominating the structure.

The size at which the effect of quantum confinement becomes important depends on the dielectric function. In Si you don't really see strong confinement until you're below around 1nm and in Ge not until around 3 nm. Most experimental crystals of this size are amorphous or are encapsulated in some surface gunk (polymer or oxide coating).

In my mind PRL is the hallmark of quality. Nature and Science are ranked higher by citation count, but the review process is really bizarre. Nature articles are interesting and entertaining, but not always trustworthy. My opinion of the quality and accuracy of the science in PRL is much greater.

Re:Read the original article, not this BS

[mr_mischief]

They can, from what I gather in the story, act as gates in a digital circuit. Which means if they can be made this small and to operate at this low of a power and actually interconnected to work reliably, then we'll have very small and efficient CPUs once that has been moved from single-gate prototype through processor prototype and into manufacturing. I'm not a nanotechnologist, a physicist, or an electronics engineer, but that was my understanding of their role pretty much as soon as they were compared to on-chip transistors for storing and forwarding values.

Link To The Physical Review Letter

[Anonymous Coward]

There's a link to the paper and some additional information at Robert Wolkow's page.

You are clearly not in physics - PRL is respected

[backslashdot]

How can you state that Physical Review Letters is not a premier physics journal??

PRL is highly respected. Maybe it's ranked 12th overall versus Nature, Science, etc which are not specialized. Also, Robert Wolkow has done well cited stuff in the past.

Are you a physicist?

Just cause you go to some mickey mouse website that supposedly ranks journals that doesn't make it a credible source either.

Re:questions from a biologist

[anmida]

There are a lot of different types of quantum dots. Some are colloidal (dots in a liquid) - others are buried or built into materials. The fluorescent dots that you are familiar with are the colloidal ones; some are made of CdSe, ZnSe, etc, and being in a liquid medium, of course they are injectable and can be used as biological fluorescent markers. In terms of color of light emitted, the bulk material emits at some characteristic color. With QDs, as you change their size, the light emitted changes color, even though you're using the same material. Larger dots emit at a longer wavelength (redder), smaller dots at higher wavelengths (bluer).

The other type of quantum dots, the ones with photovoltaic/electronic applications, tend to be dots that are buried or grown into another solid material. The "dots" that this researcher has created are of this type - basically it seems he's managed to create individual silicon atoms on a surface that have dangling bonds in a sea of non-dangling-bond Si. The fact that the dangling bond Si atoms are far-separated from each other makes them maintain their atomic energy levels instead of having their energy levels develop into bands, as what happens in typical crystalline material. It seems like these dots were developed for quantum computing purposes and are concerned with the wave functions of the electrons, as opposed to light emission and band gap energies.

Re:You are clearly not in physics - PRL is respect

[silverpig]

I also work in nanotechnology doing physics research. PRL definitely is the premier journal for physics research. Nature is probably the most popular and is where all the big discoveries go, but the articles are watered down to reach the broader audience. I've also met Wolkow - nice guy :)