Scientists at the University of Glasgow have created an unusual tribute to Her Majesty the Queen to mark her Diamond Jubilee – the world’s smallest commemorative coin, made from a tiny sliver of diamond.
The ‘coin’, created at the University’s James Watt Nanofabrication Centre, measures just 750 nanometres across and features an image of the Queen’s profile just 580 nanometres high. A nanometre is one billionth of a metre. Around 1300 of the diamond coins could fit side by side on the width of the smallest letter on a five pence piece, and 2,600 billion of the coins would fill a volume equivalent to that of a pound coin.
The image was etched on a laboratory-grown diamond covered in a special polymer. Using high-resolution electron beam lithography, the profile of the Queen’s head was patterned onto the polymer. The pattern was then transferred to the diamond using a process known as ICP reactive ion etching.
The work was undertaken at the University of Glasgow by PhD student Andrew Greer under the direction of Dr David Moran, lead of the Nano-Electronic Diamond Devices and Systems group.
Dr Moran said: “We’re proud to be celebrating the Queen’s Diamond Jubilee with the creation of the world’s smallest diamond coin.
“Diamond is not just an attractive material for use in jewellery; it also has a range of unique physical properties which make it ideal for use in a range of advanced fields of engineering. It’s an excellent thermal conductor and has a high tolerance for radiation, which makes it perfect for use in applications such as electronic transistors and robust enough to be used in challenging environments such as outer space.
“We’re researching a wide range of practical applications for diamond technology and creating this diamond coin is an excellent way to demonstrate the capabilities of the James Watt Nanofabrication Centre.”
The James Watt Nanofabrication Centre houses more than £20 M of nanofabrication tools in a 750 square-metre clean room environment. The Centre is collaborating with more than 90 different universities and research institutes around the world. Kelvin Nanotechnology Ltd. provides commercial access to the Centre’s facilities and expertise. More than 250 companies have benefited from nanofabrication services delivered by Kelvin Nanotechnology Ltd.
Previously the researchers from the University's School of Engineering fabricated a 50 nm gate length transistor on a small diamond chip. This is the smallest device yet fabricated in the diamond system. A picture of the device and the diamond chip on a finger to gauge the size is shown in the picture to the right.
D.A.J. Moran et al. "Processing of 50 nm gate-length hydrogen terminated diamond FETs for high frequency and high power applications" Microelec. Eng. 8, 1067 (2009): doi:10.1016/j.mee.2010.11.029
The work at Glasgow is predominantly aimed at the high frequency performance of diamond transistors and an example of the high speed characterisation is shown to the right for a 150 nm gate length transistor which has a cut-off frequency of 43 GHz. Work is progressing to increase the frequency through scaling the device to smaller dimensions.
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