Folding Nanosheets To Build Components
Nakeot writes "In the continuing efforts to build faster and smaller components, a group of researchers at MIT have constructed a basic prototype device that folds materials only hundreds of microns across. Mechanical engineer and Associate Professor of Mechanical Engineering George Barbastathis leads the charge into 'nano-origami' machines involving, the article reads, 'a new technique that allows engineers to fold nanoscale materials into simple 3-D structures' (more details available on MIT's page). The group had worked in 2005 with MIT Associate Professor Yang Shao-Horn to build a single-fold nano-capacitor (PDF, or see Google's HTML version), and this work appears to automate their 2005 process. A comment on the posted video appears to suggests this device is not completely automated yet, however. (This should not be confused with Paul Rothemund's slightly-more-ahead DNA-origami technology.)"
That bit they are folding over is ~500 um (half a mm) - that's easily big enough to see with the human eye, and you could probably fold that over if you were careful with a pin or something. This certainly isn't yet small enough to integrate into IC's and stuff. (or at least if you did you would be limited to a few capacitors per IC). I can see it could possibly be useful for charge pumps on some chips, for example for flash memory erase voltages or LCD drive voltages. Allowing a few reasonably large value capacitors on the die of a chip could mean pins could be eliminated, which reduces cost. Currently many IC's have pins specially for capacitors which could be eliminated with this. It also reduces external circuitry, reducing total device costs.
The capacitor they created occupied less than 1 square millimetre, but had a capacity of 1.0 uF. Lacking were specifics on break down voltage and on how long they can hold a charge. The micro-capacitor was tested at 0.6 volts and was bi-polar. This research suggests that 5 Farads per gram is a reasonable figure for super capacitors made with carbon electrodes employing sulfuric acid as the electrolyte. Imagine a cluster of these occupying, say, a cubic inch. That could yield thousands of Farads. If the capacitor can hold a charge for a considerable length of time, this indicates a considerable capacity for storing a charge to power small devices, even laptops.
First of all, it is *micro*, not *nano*-anything -- you can see structures "hundreds of microns" across with your bare eyes! :)
Second, why go into the whole folding business, if it is just a single fold (or small number of folds)? Just etch an airbridge in standard microelectronics process and fill it with electrolyte -- I would expect one could achieve much smaller plate-to-plate distances this way.
But other than that, looks cool! :)
Paul B.