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A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 1 6
2 8
has been obtained by energetic phys-
ical vapor deposition (PVD) methods.
Problems associated with the forma-
tion of phase-pure c-BN are discussed
in the literature[15-16].
SUMMARY
Q-carbon is a metal or semicon-
ductor, and has robust ferromagnetism
at room temperature with a Curie tem-
perature above 500K, suitable for use in
biocompatible implants and magnetic
sensors. Q-carbon is harder than dia-
mond because the C-C bond length is
smaller than that in diamond, making
it well suited to applications in high
speed machining and deep sea drilling.
Further, its low work function and neg-
ative electron affinity have applications
in efficient display devices.
The diamond phase nucleates in
the Q-carbon and grows in the form of
nanodots, microdots (microcrystals),
nanoneedles, andmicroneedles. Growth
depends on the time allowed during
the quenching cycle via homogeneous
nucleation and growth. Large-area sin-
gle crystal films form if an appropriate
epitaxial template is provided for do-
main matching epitaxy. Diamond can
be doped with both n- and p-type dop-
ants, which is critical for solid-state de-
vices. So far, only p-doped diamond was
created by CVD. This opens up the field
of diamond transistors and high-pow-
er devices needed for advanced power
grids and high-speed digital communi-
cation. Diamond can also be deposited
on heat-sensitive substrates at low tem-
peratures, as pulse laser heating is con-
fined primarily into the carbon layer.
This discovery is of interest in
other fields as well, because the ferro-
magnetism in carbon (liquid carbon
and Q-carbon in the Earth’s mantle)
can explain the protection of Earth
from solar plasma and flares. A similar
breakthrough has been discovered in
BN, creating Q-BN and its direct conver-
sion to c-BN (cousin to diamond) and
diamond/c-BN epitaxial composites.
These materials are critical for creat-
ing the next-generation power grid and
information superhighway, replacing
today’s bulky transformers and other
components. ~AM&P
For more informa-
tion: Jagdish (Jay)
Narayan is the John
C.C. Fan Family Distin-
guished Chair in Ma-
terials Science, North
Carolina State Univer-
sity, EB I, Suite 3030,
Centennial Campus,
Raleigh, NC 27695-
7907, 919.515.7874,
,
.
Acknowledgments
The authors are
grateful to the Fan
Family FoundationDis-
tinguished Chair En-
dowment for Professor
J. Narayan; the Nation-
al Science Foundation,
which partly funded
this research; and for
technical assistance
and useful discussions
with John Prater, Jim
LeBeau, Weizong Xu,
and Jerry Cuomo.
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