Nanoscale Crystals May Be The Future of Silicon

Wire Tap writes: "With all the talk about how silicon is nearing its physical limits in computer systems, and other data processing applications, I found this article quite interesting. "[Brian] Korgel and chemical engineering professor Keith Johnston have found a method to make stable microscopic nanocrystals out of silicon that can emit light. And by toying with the size of the silicon nanostructures, they can change the color of the light that shines through. It can make essentially faster memory and generate less heat and radiate less power.""

Re:There is one important compenent missing

[pausz]

Many people have investigated ways to incorporate or directly synthesise nanocrystals inside zeolites. Zeolites are large, open aluminosilicate structures that may act as a good framework for this. They contain cages that can control the size of the nanocrystals. Also, the cages are at fixed distance, and connected by pores (tunnels). The good thing is that you can make a wide variety of zeolites that have different geometries.

There was a very big interest in putting Cadmium sulfide inside zeolites. But it's not all that simple to get the crystals in place, and plugging the holes with sulfur is a big problem. Also, IF this works, no one knows how to incorporate these devices into something useful.

Synthesis is not the hardest step

[pausz]

This process doesn't seem new to me, because it looks surprisingly like the one a French group has invented a few years back. (Do a search for Fievet, and Polyol process). I think Fievet even has some patents on the synthesis procedure.

There are actually many physical methods to make nanocrystals of inorganic materials: ball milling, synthesis in a cavitation field, spray pyrolysis. There are also many other (wet) chemical techniques, of which this is one: water/oil microemulsions, polymer solutions.

The problem with the physical methods is the particle agglomeration, as was indicated in the article. However, the chemical synthesis methods also have problems, since you're stuck with a templating agent that surrounds your nanocrystals. This may be hindering any practical use of the nanocrystals... But you can't burn off the templating agent, because then the particles will agglomerate again.

Links to more info on nanocrystalline tech

[Goldenhawk]

This link [smalltimes.com] from July 24th on the same site is actually a good description of some further applications of nanoscale crystals, ranging from lasing to solar cells to bone implants.