Characterization of InGaN Thin Films and Nanowires by Analytical Transmission Electron Microscopy

This research is started from the chemical analysis of InxGa1-xN (InxGa1-xN/GaN) thin film heterostructures, which were grown on sapphire substrates. The nominal concentration is not always very reliable and therefore needs to be measured by analytical transmission electron microscopy. Electron energy loss spectroscopy (EELS) and energy-dispersive X-ray spectroscopy (EDXS) in a JEOL JEM 2010 F field emission gun TEM have been combined in the first part of this thesis, to evaluate the local indium concentration in those InxGa1-xN thin films. The quantification of In concentration from EDXS is based on our X-ray absorption correction method, which provided a consistent In content, quantified from Ga K and Ga L X-ray lines. The results can serve as a calibration point for evaluating the bulk plasmon energy in low- loss EELS, as a function of In concentration.