Electron Microscopy Group |
We are well-equipped for electron microscopy studies through the research of Professor David Cherns, Professor John Steeds and Dr Roger Vincent and their groups. Currently, we have four transmission electron microscopes (TEMs) and two scanning electron microscopes (SEMs): we have a range of equipment for sample preparation, including mechanical and chemical polishing equipment, dimplers, ion thinners and access to a focussed ion beam thinner. |
JEOL 2010
TEM, acquired by the Group in 2006
|
|
Convergent beam electron diffraction pattern (with acknowledgement to Dr B Krause) |
We do imaging, diffraction (in particular convergent beam electron diffraction) and microanalytical studies. Analytical facilities include energy dispersive X-ray microanalysis (EDX), electron energy loss spectroscopy (EELS) and cathodoluminescence (CL). We work on a wide range of materials, including semiconductors, ceramics and metals. |
|
Much of our current work is on semiconductors, including the wide band gap semiconductors gallium nitride (GaN), silicon carbide (SiC) and diamond. These are of great interest for devices including light emitting diodes and laser diodes operating at blue-ultraviolet wavelengths and high temperature, high power electronic devices. The properties of such devices are, however, controlled by the presence of defects including native point defects (vacancies and interstitials), other point defects including dopants and impurities, as well as extended defects such as dislocations, stacking faults, grain boundaries and interfaces. We use TEM and SEM to clarify the nature of these defects and their influence in bulk properties . |
TEM image of a defect in Si |
|
ZnO nanorods grown in an aqueous solution |
We also work on semiconductor nanoparticles, including Li-doped nanodiamond for flat panel displays and renewable energy devices, and a range of nanorod structures grown in-house. The latter include ZnO nanorods, which are of interest as intense UV-emitters, new types of phosphor, or as magnetic materials when doped with elements such as manganese (Mn). More information on this emerging area of research can be obtained by contacting Professor David Cherns (d.cherns@bristol.ac.uk) or Dr Roger Vincent (r.vincent@bristol.ac.uk)
|
