A transistor consisting of only a single atom has been achieved, according to an article published in Nature Nanotechnology on the 19th of February 2012. The transistor was created with a phosphorus atom in a silicon crystal, with the phosphorus replacing exactly one silicon atom. This single-atom-device has been made considerably earlier than was predicted by Moore’s law.
What is a Transistor?
A transistor is a device based on a semiconductor material, which can amplify and/or switch an electronic signal. To do this, the transistor has to be connected to an external circuit by at least three terminals.
Transistors are essential in for our modern lifestyle, as they are employed in almost every electronic object we use. Computer microprocessors or mobile phones, for instance, can function only due to the presence of transistors with appropriate characteristics.
Transistors Getting Smaller
In recent years, average transistor dimensions have become smaller and smaller, thanks to advances in materials and nanotechnology. The reduction in transistor size makes it possible to use more transistors in every device, which improves the efficiency of the device.
This miniaturization, and the consequently higher number of transistors employed by devices, is described by Moore’s law: according to this law, the number of transistors on a single chip of a computer doubles in a period approximately every two years (between 18 and 24 months). The law dates back to 1965, when Gordon Moore, cofounder of Intel, observed this trend for the transistors existing at that time.
Reaching the Limits of Moore’s Law
The miniaturization described by Moore’s law, however, cannot continue forever; a limit is eventually reached, when the smallest possible transistors are employed. This happens when the transistors are made only by single atoms; in these cases, it is not possible to reduce their sizes anymore. According to Moore’s law, this limit should have been reached by the year 2020.
A study published in Nature Nanotechnology in February of 2012 may indicate that the limit, or the transistor at an atomic scale, has been already reached, earlier than predicted by Moore. Researchers from the Australian Centre of Excellence for Quantum Computation and Communication Technology (Sydney, Melbourne – Australia), in cooperation with the Korea Institute of Science and Technology Information, (Daejeon, South Korea), and the Birck Nanotechnology Centre (Indiana – US) have reported the fabrication of a single atom transistor.
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