Structural characterization of InGaN thin films and multiple quantum wells: an approach of combining various X-ray scattering methods

We have evaluated the structural and chemical properties of InGaN films and InGaN/GaN multiple quantum wells (MQWs) using various X-ray scattering methods such as high-Q diffraction, anomalous X-ray scattering reciprocal space mapping, and grazing incidence X-ray scattering. The strain and the indium composition of InGaN films are determined from the reciprocal space maps near the (1 0 1 3) and by anomalous X-ray scattering spectra obtained near the In K absorption edge at the InGaN (0 0 0 6) Bragg peak. Combining the anomalous X-ray scattering spectra and regular X-ray diffraction pattern, the Poisson’s ratio of InGaN is determined to be ν≈0.23. The structure of MQWs is also investigated at high-Q ranges including the (0 0 0 6) and the (0 0 0 8) Bragg peaks where InGaN Bragg reflections are well resolved from the GaN reflections.