(V)EELS Characterization of InAlN/GaN Distributed Bragg Reflectors

摘要: Ten-period InAlN/GaN distributed Bragg reflectors are examined by aberration corrected scanning transmission electron microscopy and valence energy-loss spectroscopy (VEELS) with sub-nanometric spatial resolution sub-eV energy dispersion. Deconvolution peak subtraction methods, implemented in Matlab routines, applied to the low loss region of obtained VEEL spectra retrieve information about band gap chemical composition, whereas a Kramers-Kronig transformation is used complex dielectric function material. The measurements reveal significant compositional variations InAlN layers show ~2nm thick layer high indium content at each GaN/InAlN interface.