

Self-Assembly Shows Promise for Extending Moore’s Law - cryptoz
http://www.technologyreview.com/news/528921/self-assembly-shows-promise-for-extending-moores-law/

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rwallace
What exactly is the holdup with extreme ultraviolet sources? I remember
reading an article that said synchrotrons could generate x-ray beams with the
power density of a blowtorch, and some others suggesting free-electron lasers
should be able to generate anything down to hard x-rays with more or less
arbitrarily high power density; why don't these suffice?

~~~
gilgoomesh
The reliable sources for high-power EUV light (synchotrons and free-electron
lasers) are all expensive and gigantic (building sized) due to the accelerator
and shielding required for the electron beam. They're completely impractical
for industrial scale manufacture (you fundamentally couldn't put 100 of them
into a single factory).

Heating tin in a regular laser until it forms plasma and starts emitting 13.5
nm light is much simpler to scale down (since it doesn't involve an
accelerated electron beam) but you lose large amounts of power while trying to
form a partially coherent beam out of the result, turning hundreds of
kilowatts of infra-red laser power into mere 10's of watts of EUV power.

The high input to output ratio means that you need to be _really_ careful that
the large amount of dissipated power doesn't cause problems. Tiny misalignment
problems often result in the 200kW infra-red input laser melting the entire
device into a puddle of former components.

[http://www.eetimes.com/document.asp?doc_id=1321162&page_numb...](http://www.eetimes.com/document.asp?doc_id=1321162&page_number=2)

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tempestn
Maybe before long we'll start seeing subatomic transistors, along these lines:
[http://gizmodo.com/5793926/researchers-build-a-transistor-
ou...](http://gizmodo.com/5793926/researchers-build-a-transistor-out-of-a-
single-electron)

Or some more possibilities: "In the long term, new switches might be based on
magnetic, quantum or even nanomechanical switching principles. One possibility
would be to use changes in the spin of an individual electron to represent a 1
or a 0."[1]

[1] After the Transistor, a Leap Into the Microcosm (2009)
[http://www.nytimes.com/2009/09/01/science/01trans.html?pagew...](http://www.nytimes.com/2009/09/01/science/01trans.html?pagewanted=all)

~~~
tedsanders
Actually, the transistors mentioned in that article are still bigger than
atoms. A single electron stores a 1 or 0, but that electron is still living in
a pile of atoms.

(Source: I grew some of the crystals used to build those transistors in the
article)

~~~
tempestn
Good point. Still, the 1.5nm scale they mention is significantly smaller than
anything we have now.

Is it conceivable that we _will_ see a whole new type of electronics on a
subatomic scale in the future though? (Where the structure of a chip is not
even made out of atoms, but entirely of subatomic particles?)

I actually have an electrical engineering degree, but the couple of materials
courses I took back in the early 2000s are starting to feel a bit dated!

~~~
tedsanders
It's hard to rule anything out, but I think using non-atomic matter would be
very difficult for a few reasons.

(1) Subatomic particles are not necessarily smaller than atoms. Even though in
the particle sense, an electron is infinitely small, in the wave sense, an
electron can extend over a volume much larger than a single atom. So it's not
necessarily the case that a subatomic particle like an electron is smaller
than an atom. (Also, the positive charge of the nucleus actually helps shrink
the electron's range. So adding positive particles can end up making the
system smaller.)

(2) If you want a transistor every 1.5 nm, then you probably need at least one
particle every 1.5 nm. And the only way you can pack matter that densely is if
it's charge neutral (a clump of singly charged particles would immediately
disperse from electric repulsion). So you either need a combination of
positive and negative particles (atoms), or neutral particles like
photons/neutrons/neutrinos. The problem with neutral particles is that there's
no long-range forces to keep them in whatever structure you design. Gravity is
too weak at that scale, and electromagnetism has no effect because they are
neutral. Perhaps photons could be used for computation, but without using
atoms for mirrors/lenses/waveguides/etc it's hard for me to imagine how.

TL;DR: Atoms are an efficient way to pack particles and preserve structure.
It's hard to imagine doing it with a plasma or gas or something else.

~~~
keeperofdakeys
[http://www.scientificamerican.com/article/optical-
circuits-s...](http://www.scientificamerican.com/article/optical-circuits-
single-photon-flips-transistor-switch/) There has been some (very early) work
done with photon transistors. One of its cool applications will be fibre-optic
hardware, to achieve much lower processing latency, hence faster data transit.

------
hyp0
Lithography guiding finer block copolymers pleasingly follows Feynman's
pantograph talk
[http://www.zyvex.com/nanotech/feynman.html](http://www.zyvex.com/nanotech/feynman.html)

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navbaker
I can't be the only person who immediately thinks of the Replicators from SG-1
when self-assembling materials are brought up, right?

~~~
ChuckMcM
Well you can be forgiven for that :-) That particular plot device was full of
holes.

But a more interesting associated memory would be Eric Drexler's "Engines of
Creation" and the discussion about obstacles to nanotechnology which include
high on the list the ability to actually assemble devices.

~~~
mrfusion
What were the plot holes with it?

~~~
todayiamme
Fundamentally, we already have self-replicating robots with nano-level
structures that consume materials from their surroundings and build new
copies. They're called bacteria. The interesting bit over here is not the
observation, but the question why we aren't all covered in bacterial goo miles
thick like run-away nano-technology. (we do have them all around us and in us
for what its worth)

I think a part of the answer is that if you have free form replication that
isn't perfect, then sooner or later something is going to emerge from that goo
that realises that it's just more efficient to eat the goo. Combine that self
correcting cycle with hard limits imposed by nature (presumably they need to
have a power source to make it work - the goo would start to die the minute it
gets to a millimetre because of inaccessible sunlight. Then there is toxicity,
what happens to the waste? Heat dissipation. Structural issues and other
things...) and you have the recipe for a shorter sci-fi series than Firefly.
(Dear Mark, today we succeeded in making self replicating nano-robots. They
were exponentially multiplying within the petri dish and then they stayed in
the petri dish, because apparently nano-robots are tastier than glass and
metal. Doesn't matter though, we cracked open the crate of champagne anyway.)

Which is also an argument against von Neumann probes, btw. Perfect replication
isn't possible, so sooner or later you are going to see a ton of weird errors
accumulate to unpredictable behaviour... (perhaps a shark that goes around
"eating" other probes?)

~~~
lukeschlather
Bacteria aren't capable of spontaneously organizing into multi-celled
organisms when they reach critical mass.

Fungi behave much more like this. The thing we don't have an example of in
nature is an intelligent creature capable of making tools that can reproduce
itself from a single cell. It's definitely a hard engineering problem, but
it's conceivable. It's also conceivable that such an entity could seek out and
remove any malfunctioning sub-entities.

We humans actually behave a lot like that, it's just that you need at least a
whole human to grow another human. It's not so strange to imagine a designed,
intelligent creature that can regrow itself from a small piece.

------
ingenter
Yay, humans are re-inventing proteins!

