The University of Bath is inviting applications for the following PhD project supervised by Prof Alain Nogaret in the Department of Physics.
Van der Waals heterostructures envision atomically thin layers with tailor-made electronic properties.1 However, the materials that embody this vision are limited to a few two-dimensional inorganic crystals that have lattice-matched unit cells.
The purpose of this studentship will be to fabricate all organic van der Waals heterostructures and probe their electronic properties in particular on flexible substrates. The novel concept underpinning these structures is to intercalate self-organised 2D molecular crystals in-between graphene sheets. In this way, one obtains quantum tunnelling devices and superlattices which may exhibit the full range of theoretically predicted properties rather than being restricted by substrate rigidity or by the lattice-matching properties of inorganic 2D materials as is currently the case in conventional Van der Waals structures.
We will use N,N´-bis[2-(4-pyridyl)ethyl]-naphthalene diimide molecules (NDI-Py) and their derivatives to form the 2D molecular crystals. These molecules develop molecular interactions on three energy scales: Van der Waals, carbonyl-hydrogen and ion-dipole.
- the NDI cores anchor to graphene via van der Waals interactions.
- they then self-organize in the plane of graphene through carbonyl-hydrogen interactions2 into almost crystalline 2D monolayers which form the tunnel barrier. This layer is lattice matched to graphene and has electronic properties that can be designed independently of the graphene lattice constant.
- finally, Van der Waals junctions are assembled at room temperature by clipping the Py endings of NDI molecules with ion-dipole bonds.
In this way graphene ribbons and organic tunnel barriers can be stacked into Van der Waals multilayers. The proof of principle of these devices has been demonstrated in our group.3
The project will focus in building organic tunnelling trilayers and more complex Van Der Waals heterostructures on flexible PEN substrates. Chemical synthesis in the group of Dr Pantos further opens the unique possibility of tuning electronic properties by doping graphene, or tuning tunnelling barrier parameters. Tunnelling transport will be measured using sensitive electronics in Prof Nogaret’s lab, in magnetic fields, cryogenic temperatures and as a function of the bend radius of the substrate. The self-organisation of molecular crystals will be probed in Dr Ilie’s STM lab, and in the MC2 centre (Raman).
Candidate requirements:
Applicants should hold, or expect to receive, a First Class or good Upper Second Class Honours degree (or the equivalent) in Physics, Natural Sciences or Chemistry, and should have enthusiasm for experimental nanoscience. A master’s level qualification would also be advantageous.
Non-UK applicants will also be required to have met the English language entry requirements of the University of Bath.
Enquiries and applications:
Informal enquiries are welcomed and should be directed to Prof Alain Nogaret, [Email Address Removed].
Formal applications should be made via the University of Bath’s online application form for a PhD in Physics.
More information about applying for a PhD at Bath may be found on our website.
Further information:
On our website, you will also find information about tuition fees, understanding your fee status and how to estimate your living expenses in Bath.
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