Small Transistors

How often do you get attracted to an article somewhere because of its outrageous headline, and then discover on reading the article that its headline, if not an outright lie, doesn't quite represent what the article is actually about?

This is one that got my attention earlier this week on physorg.com.  The headline "Scientists build 'single-atom transistor' " certainly promises a lot. Getting ever-decreasingly small transistors is what has driven computer and electronics technology forward at such a blistering pace. But there is (probably?) a fundamental limit - when a transistor is the size of an atom it can't be made any smaller. A single atom transistor (or just a few atoms transistor) is one of the holy grails of nanotechnolgy. So are we there now?

Hmmm. No, not really. The clue was in the '...' quotation marks around 'single-atom transistor'. What is really meant is that researchers have studied the effect of single phosphorous donor atoms in silicon. That is not the same as building a single-atom transistor - although it might exhibit measurable effects due to single phosphorous atoms, the device itself is much bigger than a single atom. After a bit of trawling with search engines I recovered the original paper on which this headline is based. Unsurprisingly, at no point in it do the researchers claim to have build a single-atom transistor. Kuan Yen Tan et al, Nano Lett., December 1, 2009 (Letter), DOI: 10.1021/nl901635j.

Moral: In case you didn't know, don't believe everything you read.