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In a collaboration with Waseda University in Tokyo, London Centre
for Nanotechnology (LCN) researchers have grown highly boron doped
diamond layers only 1 nm in thickness, a technique known as d-doping,
for the realisation of high performance field effect transistors (FETs).
When used in a novel configuration, where the normal metal gate that
controls the transistor is replaced by an ion containing solution, such
devices offer the prospect of highly sensitive detection of biochemical
agents, or even action potentials from living cells.
Professor
Richard Jackman, who heads the LCNs Diamond Electronics Group, stated
“this is the first time that the (111) crystal plane of diamond has been
used to generate such heavily doped yet so incredibly thin layers. The
resulting transistors offer very good gain and transconductance values
when compared to similar devices.”
The
work was performed in a collaboration between the LCN and Professor
Kawarada’s Diamond Devices team in Japan, with the secondment of Robert
Edgington, a PhD student with the LCN team, to Waseda University for
five months being made possible through a Japan Society for the
Promotion of Science (JSPS) award. Edgington found the experience
valuable beyond just science, “to spend five months immersed in Japanese
culture was transforming for me,” said Robert, who had the opportunity
to practice the Japanese language he had been studying in London prior
to his visit.
“Diamond
surfaces offer a unique platform for chemical functionalization for the
purposes of biosensing,” states Professor Jackman, who continued, “we
have encouraging initial data on the detection of PDGF, a growth factor
linked with the promotion of cancer, using aptamers bound to the surface
of the gate of the diamond transistor.”
Robert,
who will continue similar work as a Postdoctoral Research Fellow with
the UCL Diamond team, added “the work was very hands-on, with the
development of diamond growth and doping techniques, the design of FET
device structures, and the manipulation of biochemical species,
representing a truly interdisciplinary activity.”
Boron ?-doped (1 1 1) diamond solution gate field effect transistors
Source: London Centre for Nanotechnology
