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Electrical components

While you may have read my glowing article on the promise of molecular electronics, I should warn you that it doesn't solve all of our problems.  The thing is, many important electronics applications require reliable semiconductor materials.  Using molecules is a novel way to tackle the problem, but it also introduces new problems that you won't run into when dealing with run-of-the-mill semiconductors.

Granted, individual molecules are smaller, but in terms of engineering they represent a nightmare.  We haven't solved the problem of protein folding, and it will be some time before molecular electronics really gets rolling.  In the meantime, it's up to semiconductor nanoelectronics researchers to come up with ways to do the same task with traditional nanotechnology structures like quantum dots and nanowires.

Most problems with these two structures are the result of our inability to quickly position or self-assemble them on a substrate.  Quantum dots typically exhibit better self-assembly characteristics, but even then it's not on the level of what we'd need for an integrated device.

Let us discuss the developments in nanoelectronics so far.  The fundamental component of electronics is the p-n junction, or diode.  This is the piece in a circuit that restricts current flow in one direction only.  The 'p' and 'n' refer to the semiconductor type (hole and electron, respectively).  You need both kinds to make integrated devices.  One way to make a p-n junction is to make a physical crossing between a p-type nanowire and an n-type nanowire.  Another way to do it is to dope a single nanowire with p- and n-type regions.  Either way, these basic components have already been fabricated and used as simple LEDs.

The next step in electronic device fabrication is the holy grail of digital logic: the logic gate.  Digital logic is the governing principle behind all computations in electronics.  On a single microchip, there are millions of logic gates.  Researchers have successfully made nanowire logic gates by connecting several nanowire p-n junctions in series.

We've already discussed the quantum dot's role in laser applications, so I won't tread over that again.

My point here is that nanowires and quantum dots have found many uses in electronics applications that are more traditional in comparison to the molecular electronics field.  Though neither field has made significant breakthroughs yet, one or the other will likely find a key to unlock its true possibilities within the next few years.