On Sunday, February 19, Australian and American physicists working at Purdue University and the University of New South Wales reported in the journal Nature Nanotechnology that they successfully built a working transistor from a single atom using a reliable and repeatable process.
Transistors are the fundamental building blocks of computers and many other modern electronic devices; a contemporary computer has potentially hundreds of thousands of transistors on one processing chip. Transistors are used to encode, transfer, manipulate, and store all kinds of data using binary digital form, as well as to amplify signals. The transistor is also cheaply and reliably mass produced, making it an even more integral part of modern electronics. Without transistors, computer processing power would be very limited and nearly all of the electronic devices we use today wouldn’t exist.
The number of transistors on a processing chip related directly to the chip’s speed and processing capabilities. Unlike contemporary transistors, which are either “on” or “off,” a single-atom transistor can be both “on” and “off” at the same time. Combined with the transistor’s size, this immensely increases the potential computing power and speed of a processor using these transistors. Encryption and codes that baffle even the best contemporary computers would be easy work for the processing capabilities of a quantum computer.
Though transistors have successfully been made from single atoms as early as 2002, they weren’t placed with complete accuracy, leaving a margin of error in the location of the transistor, which in turn limits the transistor’s practical use. This most recent transistor, however, was placed with atomic precision using a repeatable method, allowing researchers to pinpoint the atom’s location and more efficiently and reliably control the transistor. The researchers accomplished this exact placement using a scanning-tunneling microscope to place a phosphorus atom among a bed of hydrogen atoms, the whole of which was encased in layers of silicon.
This creation of a single-atom transistor shows the eventual physical limitations of Moore’s Law. Moore’s Law describes an exponential, long-term trend in the history of computing hardware. According to Moore’s Law, the number of transistors that can be placed on an integrated circuit doubles roughly every two years while the cost remains inexpensive. Intel executive David House interpreted Moore’s Law in the context of chip performance, which doubles every 18 months. This trend has continued for more than half a century.
The single-atom transistor comes several years earlier than Moore’s Law would have anticipated. The tiny transistor, however, must be kept at -391 degrees Fahrenheit. Though the process used to create the transistor is reliably repeatable, the accomplishment is not a step towards the manufacture of such transistors, but rather, proof that they are possible.
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