Postgraduate research opportunities Pushing the limits of diffraction techniques in the scanning electron microscope for the structural characterisation of novel materials

Electron backscatter diffraction (EBSD) is a scanning electron microscope (SEM) technique used to characterise the structural properties of materials. There have recently been substantial developments in both EBSD hardware and software, enabling significant improvements in the speed, spatial resolution and sensitivity of this technique.

This means that it is now possible to map and quantify crystal orientation, crystal phase and strain and image and identify extended defects such as such as dislocations, stacking faults and antiphase domains in semiconductor materials with a spatial resolution of around 30 nm.

This is important because, to achieve the best performance from the next generation of semiconductor-based devices, it is crucial that we understand and optimise the structural properties of the new materials used in their manufacture. For example, the lifetime and optimal performance of nominally single crystal semiconductor thin film based electronic and optoelectronic devices is often limited by structural defects and strain. Conversely, strain is a parameter which can be exploited to enhance device performance, for example increasing light emission from LEDs. Defect engineering can be used to functionalise a material, for example by creating single quantum emitters. For solar cells based on polycrystalline semiconductors, the microstructure (grain orientation, orientation spread, grain size, grain boundary type) can also significantly influence lifetime and device performance.

Within this project the student will have opportunities to participate in new hardware and software developments, for example in the development of novel direct electron detectors and/or in developing and applying advanced data and image analysis software. They will also have opportunities to carry out research to support the optimisation of a range of new semiconductor materials ranging from nitride nanostructures under development for the production of high-performance UV LEDs for medical applications, to halide perovskites which are under development for the production of flexible solar cells to be used in the home. The student may also explore how the structural properties influence other material properties such as light emission through correlating EBSD measurements with maps of light emission acquired using hyperspectral cathodoluminescence (CL) imaging.

The emphasis of the project will be driven by the interests and aptitude of the student.

Further information

This project is available for self-funded students. Scholarships (fees and stipend) are available on a competitive basis for UK students, please contact supervisor for details.