Tyndall researchers on a road with no junctions
Transistors are an integral building block of all modern electronic devices. Their function is to either amplify or switch electronic signals, and since their invention in the 1940s, their size has continued to be reduced dramatically, allowing devices to be made smaller and to have more powerful storage and calculating abilities. As a consequence, computers that used to fill whole buildings are now comfortably sitting on your lap, and the mobile phone of today not only has the capability to call your cousin in Australia, to direct you to the nearest cashpoint, and to play the latest Lady Gaga album, but is also small enough to be easily lost down the side of your settee.
Traditionally, transistors are prepared from two distinct types of a semiconductor material (usually silicon), where one is rendered with a positive charge and another with a negative charge by adding atoms of other chemical elements into the silicon. These two types of silicon are brought together to form sandwich-like structures called junctions. Electric current cannot flow from one side of the structure to the other (that is, the device is an “off” switch) unless an input signal is applied to close the switch. As the size of these components become ever smaller, the ability to reproduce junctions successfully at the required scale becomes significantly more challenging.
Now, an SFI-funded team from the Tyndall National Institute in Cork appear to have overcome this problem by developing the world’s first junctionless transistor. As reported in the prestigious journal Nature Nanotechnology, Prof. Jean-Pierre Colinge and his team have used silicon nanowires, materials that have a diameter of around 10 nanometers (approximately 10,000 times thinner than a human hair!) to prepare minute devices that act as excellent transistors but do not require junctions to perform. The scale and electronic properties of these devices are such that they can be envisaged as providing an answer to one of the biggest questions that exists in electronics technology, namely, how can we reduce the size of components in order to continue the advancement of the electronic age?
Prof. Colinge cautions us by admitting that there is still a long way to go before his group’s discoveries might find their way into your mobile phone or laptop. However, he notes that “there is great potential for these devices to overcome the challenge of Moore’s Law (a well-known relationship outlining the need for year-on-year reduction in the size of electronic components) for many years to come”.
