February 21, 2009

Are We Getting Enough Capabilities with Self Assembly, Directed Assembly and Pick And Place to Kluge together Molecular Manufacturing ?

We are looking at faster computing developments based on recent breakthroughs. There are now several ways that we can get computing down to 1-2 nanometer feature or element size. These manufacturing methods could be scaled up and delivering computer hardware products within 4-10 years. Many thought that computer hardware might permanently stall at 10-20 nanometer feature sizes. Now it seems that 1-2 nanometers is certain within 10 years. 100-400 times smaller in area and 1000-16,000 smaller in volume.

1. The self assembly of 10-100 terabit per square inch magnetic memory. They have self assembled several square centimeters and the process appears to be compatible with current computer chip fabrication processes. They seem confident in adapting the self assembling process to produce photonic and computing elements.

2. The room temperature quantum dots based on dangling silicon bonds.

3. More durable and higher density nano-imprinting is working at 13 nanometer features and they seem confident about going to 1-2 nanometers.

4. Oxide Nanoelectronics on Demand (University of Pittsburgh)

Electronic confinement at nanoscale dimensions remains a central means of science and technology. We demonstrate nanoscale lateral confinement of a quasi–two-dimensional electron gas at a lanthanum aluminate–strontium titanate interface. Control of this confinement using an atomic force microscope lithography technique enabled us to create tunnel junctions and field-effect transistors with characteristic dimensions as small as 2 nanometers. These electronic devices can be modified or erased without the need for complex lithographic procedures. Our on-demand nanoelectronics fabrication platform has the potential for widespread technological application.

Rather than building them from silicon, the team used two different forms of the common mineral perovskite. When two of the insulating crystals of the right thickness are held together, the place where they meet can conduct electricity. But if one of the pieces is too thin, then current will not flow.

Working with wafers that were just too thin to conduct, Levy's team found that they could "draw" conducting patches onto the crystal using a microscopic needle. A positive voltage from the needle rearranges the crystal's atoms to create lines 2 nm across that conduct like electrical wire.

Write and erase

The process has been used to make transistors roughly 1000 times smaller in area than those fashioned from silicon. The "wires" can also be easily erased and recreated up to 100 times.

Being able to erase parts of a design and write over them again also offers more exotic possibilities, says Levy. It could be possible to use the phenomenon to could create hardware that rewires itself as it handles data, he says.

A nanometer scale etch a sketch.

Scientists at the University of Pittsburgh say they have found a way to draw and erase tiny nanometer-wide dots and lines that can conduct electricity. The researchers showed how they could write conducting lines, or wires, less than 4 nm wide using the technique. They were also able to make an array of 2-nm-wide dots. These areas remained conductive for more than 24 hours.

5. Chemists at New York University and China's Nanjing University have developed a two-armed nanorobotic device that can manipulate molecules within a device built from DNA.

Nadrian Seeman, co-author: "This is a programmable unit that allows researchers to capture and maneuver patterns on a scale that is unprecedented."

The device is approximately 150 x 50 x 8 nanometers. In the two-armed nanorobotic device, the arms face each other, ready to capture molecules that make up a DNA sequence. Using set strands that bind to its molecules, the arms are then able to change the structure of the device. This changes the sticky ends available to capture a new pattern component.

The researchers note that the device performs with 100 percent accuracy. Earlier trials revealed that it captured targeted molecules only 60 to 80 percent of the time. But by heating the device in the presence of the correct species, they found that the arms captured the targeted molecules 100 percent of the time.

I think things are coming together for near term surge in computing capability and for various methods of manipulation and control and manufacturing at the 1 to 10 nanometer scale. Industrial scale self assembly and DNA production and control combined will lessen the requirements on atomically precise pick, place and react.

If we are sitting at the molecular fabrication doorstep with multiple substantial 1-2 nanometer capabilities, and with some slower but molecularly precise pick and place capabilities then we get within a series of doable kluges to getting onto a bootstrap path to full-blown no limit molecular manufacturing.

The "combination of substantial self-assembly and directed assembly" could be substantially in hand this year or within 3 years. We just have to creatively work the combinations and plug some gaps.
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