skip to content

Cambridge Centre for Gallium Nitride


Quantitative electron microscopy of nitride films

I investigate structure-function relationships in nitride-based films, devices and nanostructures, using transmission electron microscopy (TEM) and optical spectroscopy, combined with image processing and crystallographic simulations.

My PhD research work was on electron beam analysis of UV-emitting nitrides at the Department of Physics at the University of Bristol, focussing on using convergent-beam TEM techniques and Raman spectroscopy to investigate strain in GaN/AlGaN heterostructures. After my PhD work, I did an internship at Unilever, studying polymer brush vesical opening mechanisms by low-voltage TEM, after which I received a EU FP6 Framework Marie Curie Fellowship to study MBE-grown III-nitride nanostructures in the Nanostructured Materials Microscopy Group at the Aristotle University of Thessaloniki in Greece, which allowed me to study quantum dots, quantum wells, nanorods and high-indium content nitride films using atomic-resolution TEM.

On returning to the UK I joined the Device Materials Group at the Department of Materials where I studied the atomic structure of perovskite superconductors and multiferroics, metal oxide nanostructures and thin films, and carbon materials. Since joining the Cambridge Centre for Gallium Nitride, I have been analysing the morphology of InGaN quantum wells in LED structures, with a view to improving efficiency, reducing droop and extending emission into the green. I am also interested in the microstructure of lattice-matched InAlN films, and the growth of nitride materials for UV emission.

Dr Lata  Sahonta