ABSTRACT
Transmission electron microscope (TEM) study is the analytical method most useful for determining the thickness and composition profile of the quantum well. By using an electron spectrometer attached to the TEM, this analytical tool becomes indispensable, by providing direct measurements of the electronic structure. Spatially resolved information about the electronic structure across the barrier can be obtained by scanning a sub-nanometre probe across it and sequentially collecting energy loss spectra. Cross-sectional samples for TEM investigations were prepared by grinding and polishing, with a final stage of ion beam polishing in order to achieve electron transparency. The Gatan image filter electron spectrometer can be used to record spectra with sub-nanometre spatial resolution by exploiting the line focusing properties of its quadrupoles, and by aligning the planar interface along a particular direction and recording images of the energy loss spectrum.
