X-Message-Number: 31901
Date: Tue, 25 Aug 2009 07:50:03 -0700 (PDT)
From: 
Subject: Tiny Robots Get A Grip On Nanotubes


[I was a little surpised to see this. Below is a video showing a microgripper in
action.]

http://www.azonano.com/nanotechnology-video-details.asp?VidID=23

Science News
Tiny Robots Get A Grip On Nanotubes

ScienceDaily (Aug. 24, 2009) - How do you handle the tiny components needed for 
constructing nanoscale devices? A European consortium has built two microrobotic
demonstrators that can automatically pick up and install carbon nanotubes 
thousands of times thinner than a human hair.


Carbon nanotubes, rolled up sheets of carbon only a few tens of nanometres in 
diameter, could become an essential part of the nanotechnologist's construction 
kit. But there is a problem: how can you handle objects which are so thin that 
they cannot be seen at all with a normal optical microscope?

"The handling and characterisation of these objects has become more and more 
important in materials science and nanotechnology," says Volkmar Eichhorn of the
University of Oldenburg and its associated institute, OFFIS. "They have a huge 
application potential in various products."

One solution, developed by the EU-funded NanoHand project, is to use mobile 
microrobots equipped with delicate handling tools. NanoHand builds on the work 
of ROBOSEM, an earlier EU project that developed the basic technologies that are
now being put into effect.

The robots, about two centimetres in size, work inside a scanning electron 
microscope where their activities can be followed by an observer. "The whole 
set-up is integrated into the vacuum chamber of the microscope," Eichhorn 
explains. "There is a glass plate where these mobile microrobots can walk 
around."
Microgrippers

Each robot has a 'microgripper' that can make precise and delicate movements. It
works on an electrothermal principle to open and close the jaws, much like a 
pair of tweezers.

The jaws open to about 2 micrometres and can pick up objects less than 100 
nanometres in size. "[It is] really able to grip micro or even nano objects," 
Eichhorn says. "We have handled objects down to tens of nanometres."

At that scale, the intermolecular forces between objects are stronger than 
gravity. Once a nanotube has been picked up it will stick to the jaws of the 
gripper and cannot easily be dropped into position. The team have had to develop
novel 'pick-and-place' techniques to get around this problem.

One approach is to glue the tube in its final position using electron 
beam-induced deposition. Another is to use geometrical principles to ensure that
the intermolecular forces pulling the tube towards its intended location are 
greater than those holding it in the jaws of the gripper.

"Worldwide, we are the first project that has really realised the automated 
microgripper-based pick-and-place experiments," Eichhorn notes. "The new thing 
is the high accuracy and the small scale of the objects - in the range of tens 
or hundreds of nanometres - and the excellent control and software architecture 
being built around this whole set-up facilitating a high degree of automation."
Better microscope

An early success of the project was to improve the performance of an atomic 
force microscope, a workhorse of nanotechnology.

The microscope 'feels' a surface by dragging a fine probe over it. Individual 
atoms can be sensed and a picture built up. But conventional probes have a 
pyramid-shaped tip which cannot follow the hills and valleys of deeply 
corrugated surfaces. The NanoHand team used their microrobots to automatically 
pick up a carbon nanotube and attach it to the tip, so greatly improving the 
probe's ability to sense deep valleys.

This achievement was made with the 'NanoLab' demonstrator, designed for use in 
experimental laboratory situations.

In parallel, the industrial partners have developed a more robust 'NanoFab' 
demonstrator, better suited to the needs of industry. They are exploring how the
technology could be used for rapid prototyping of new designs for microchips. 
One idea is to use carbon nanotubes as 'interconnects', the fine wires that make
the electrical connections to a chip. Because of their high electrical 
conductivity, carbon nanotubes dissipate less heat than copper and allow 
circuits to be packed more densely.

This application is of particular interest to STMicroelectronics, one of the 
project partners and a heavyweight maker of microchips. "They would like to have
a nanorobotic system where they can do fast and rapid characterisation of these
devices," says Eichhorn. "Up to now, it was a manual, teleoperated 
characterisation which was very time consuming."
Early exploitation

Many other industrial applications are possible, including novel devices that 
could not be constructed any other way. Applications in composite materials, 
displays and new kinds of transistors are all being talked about.

Other groups are working on methods of handling nanotubes, especially in the 
USA, Japan and China, but the NanoHand system of microrobots and microgrippers 
is proving effective and reliable. "It's very promising for nanotechnology 
applications," says Eichhorn.

>From the start, the project has been run with commercialisation in mind and the
first product is already on the market. Two of the industrial partners, Tescan 
and Klocke Nanotechnik, are collaborating to sell a scanning electron microscope
equipped with a nanopositioning system based on NanoHand technology.

The Technical University of Denmark (DTU Nanotech) intends to set up a spin-off 
to market the microgrippers and the Ecoles Polytechniques Federale de Lausanne 
(EPFL) is seeking to further develop the microrobots to the point where they can
be commercialised.

NanoHand received funding from the ICT strand of the EU's Sixth Framework 
Programme for research.

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