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Professor of Materials Science
Deputy Head of Department (responsible for Teaching)

MA University of Cambridge
PhD University of Cambridge

Thin Film Deposition

My research, within the Device Materials Group, is based upon thin film fabrication using vapour deposition techniques. We are developing and optimizing the growth of many different thin-film device materials and hetero-structures, 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.

We are investigating the intriguing properties of gadolinium nitride, which shows ferromagnetism combined with electronic transport properties varying from insulating, through semi-conducting, to semi-metallic. Our understanding of GdN has greatly advanced through precise control of stoichiometry and microstructure. Ferromagnetic insulating GdN tunnel barriers have been demonstrated for the fabrication of spin-filter Josephson Junctions, and work continues towards further novel device applications using this material. We are also exploring a range of thin film superconductors for the development of high performance single-photon detectors for integrated quantum photonics.

I collaborate on a wider range of thin-film applications, for example, investigating ultra-hard coatings (e.g. nano-composites, and epitaxial nitride multilayers); fuel cell electrodes; biomedical coatings (e.g. doped hydroxyapatite); shape-memory metals; and precise free-standing structures for nanotechnology applications. Ionisation of the depositing flux during physical vapour deposition allows increased control during film growth, and we have demonstrated the ability to fabricate some novel film structures, such as nickel nano-crystals surrounded by graphitic carbon "nano-onion" shells. Deposition parameters have also been optmised to produce extremely porous, vertically oriented, nano-pillar arrays, which have potential applications in photocatalysis, and as templates for the fabrication of anisotropic, columnar functional materials structures.

Extremely precise fabrication of thin films and heterostructures is performed in ultrahigh vacuum deposition systems. The diameter of the main chamber shown is 0.6 m
  • K Senapati, M G Blamire & Z H Barber, "Spin-filter Josephson junctions", Nature Materials10 849 - 852 (2011).
  • R M Heath, M G Tanner, A Casaburi, M G Webster, L San Emeterio Alvarez, W Jiang, Z H Barber, R J Warburton & R H Hadfield, "Nano-optical observation of cascade switching in a parallel superconducting nanowire single photon detector",Appl. Phys. Lett.104 063503 (2014).
  • D A Bosworth, N A Stelmashenko & Z H Barber, "Structural control of carbon nickel nano-composite thin films without substrate heating",Thin Solid Films, 540 10 – 16 (2013).
  • W Jiang, N Ullah, G Divitini, C Ducati, R V Kumar, Y Ding & Z H Barber, "Vertically oriented TiO(x)N(y) nanopillar arrays with embedded Ag nanoparticles for visible-light photocatalysis", Langmuir, 285427 – 5431 (2012).