Electron Microscopy

Imaging, diffraction and microanalysis

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.

TEM image of a defect in Si

 

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.

Nanostructures

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).

ZnO nanorods grown in an aqueous solution

Working in this area

The following people are involved in this research:

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