Research Profile - Department of Materials Science and Metallurgy ...

Zoe Barber
Senior Lecturer
MA University of Cambridge
PhD University of Cambridge
+44 (0) 1223 334326
zb10@cam.ac.uk
www.msm.cam.ac.uk/dmg/
Thin-Film Deposition
My research interests are based around thin-film deposition
using a range of techniques: magnetron sputtering, ionized
sputter deposition, pulsed-laser ablation and sol-gel fabrication.
Within the Device Materials Group we are developing and
optimizing the growth of many different thin-film device materials,
which may be amorphous, polycrystalline or single crystal.
These include magnetic alloys and compounds, ferroelectrics,
dielectrics, superconductors, multiferroics, as well as tunnel
barriers, buffer layers, contacts and encapsulation layers.
In relation to a wider range of thin-film applications we are
investigating ultra-hard coatings (e.g. nano-composites,
epitaxial nitride multilayers); biomedical coatings (e.g. doped
hydroxyapatite); shape-memory metals and precise freestanding
structures for nanotechnology applications; and
multilayers for X-ray mirrors and for studies of interdiffusion.
Spintronics
To optimize spin-dependent transport between ferromagnetic
metals and semiconductors we are developing methods for
the deposition of ferromagnetic electrodes on insulating tunnel
barriers on semiconductors. This requires careful preparation
of the semiconductor surface using in-situ surface-cleaning
techniques in an ultra-high vacuum deposition system.
Superconducting junctions
Measurement of the spectrum of quantum fluctuations in
niobium-nitride-based superconducting tunnel junctions
may answer questions about the source of dark energy in
the universe. We are developing and optimising the fabrication
of very high critical current density, shunted NbN junctions for
this application.
Film growth techniques are being developed to further improve
the control of film structure (e.g. ion-enhanced deposition), and
we are using optical emission spectroscopy and plasma probes
for detailed diagnostics of the film growth environment.
XB Hu, A Garg & ZH Barber, “Deposition and characterization of pulsedlaser-deposited
and chemical-solution-derived Sm-substituted bismuth
titanate films” Integrated Ferroelectrics 79, 113–121 (2006).
LJ Singh, CW Leung, C Bell, JL Prieto & ZH Barber, “Magnetoresistance
of spin valve structures based on the full Heusler alloy Co 2
MnSi” J. Appl.
Phys. 100, 013910 (2006).
ES Thian, J Huang, ME Vickers, SM Best, ZH Barber & W Bonfield,
“Silicon-substituted hydroxyapatite (SiHA): A novel calcium phosphate
coating for biomedical applications” J. Mater. Sci. 41, 709–717 (2006).
S Sanjabi, SK Sadrnezhaad & ZH Barber, “Sputter alloying of Ni, Ti and Hf
for fabrication of high temperature shape memory thin films” Mater. Sci.
Technol. 23, 987–991 (2007).
MA Moram, Y Zhang, MJ Kappers, ZH Barber & CJ Humphreys
“Dislocation reduction in gallium nitride films using scandium nitride
interlayers” Appl. Phys. Lett. 91, 152101 (2007).
Extremely precise fabrication of thin films and heterostructures is
performed in ultra-high vacuum deposition systems. The diameter
of the main chamber shown is 0.6 m
Research Profile 5