Department of Physics, Unit Catalogue 2008/09 |
PH40085 Nanoscience |
| Credits: 6 |
| Level: Masters |
| Semester: 2 |
| Assessment: EX100 |
| Requisites: |
| Before taking this unit you must take PH30030 and take PH30034 |
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Aims: The aims of this unit are to outline the electrical and magnetic properties of materials at the nanoscale, to describe methods for the fabrication and visualisation of nanostructures, and to give some examples of their possible applications.
Learning Outcomes: After taking this unit the student should be able to: * demonstrate knowledge and understanding of the topics listed below; * solve problems in these areas. Skills:Numeracy T/F A, Problem Solving T/F A. Content: Introduction to nanotechnology (2 hours): Types of nanostructure; 'bottom-up' and 'top-down' approaches to nanotechnology. Examples of nanomaterials and nanostructures; superlattices, mesostructures, fullerenes. Nanofabrication techniques; e-beam lithography, etching, focussed ion beam milling, and self-assembly methods. Visualisation and manipulation at the nanoscale (4 hours): Scanning Tunnelling Microscopy, Atomic Force Microscopy, different kinds of Scanning Probe Microscopy (chemical, electrical, magnetic). Single-atom manipulation with AFM/STM, laser manipulation of atoms, atom trapping, optical tweezers. Electronic properties of nanostructures (6 hours): Ballistic/diffusive transport, Landauer formalism, conductance quantisation in nanocontacts. Tunnelling. Coulomb blockade. Conductance through a quantum dot. Energy quantisation in quantum dots. Quantum dots as artificial atoms. Single Electron Transistor: principles of operation. Co-tunnelling. Resonant tunnelling. Mechanisms of negative differential resistance. Nanomagnets, spintronics and nanoscale superconductivity (5 hours): Magnetic nanostructures (including molecular magnets); blocking temperature and tunnelling of the magnetic moment. Ferromagnetic constrictions, domain wall resistivity, current-induced domain wall motion. Spin injection. Superconductor nanostructures; mixed state, giant vortices, linear/nonlinear Ginzburg-Landau equations, surface superconductivity. Nanomagnetometry, pinning and pinning arrays. Molecular electronics (5 hours): Atomic orbitals. Orbital energies. Hybridisation of orbitals. Shapes of molecules. Energy of molecular orbitals. HOMO and LUMO states. Mechanisms of charge transfer in molecules. Electron transport in conjugated oligomers (?- and ?-bonds, delocalised electronic state). Metal-molecule-metal junctions. Contact resistance. Double barrier tunnelling. Carbon nanotubes; atomic structure, methods of fabrication, band structure, conducting and semiconducting nanotubes, electron transport, applications. |