Indium distribution and influence of internal fields in InGaN quantum wells

A detailed structural and optical characterisation of InGaN/GaN multiple quantum wells with In content up to 6% is presented. High resolution X-ray diffraction was employed to determine with a good accuracy the In content in the wells. Transmission electron microscopy did not show significant In fluctuations in the wells, in agreement with X-ray diffraction results. SEM-cathodoluminescence spectroscopy measurements taken at different injection powers allowed us to obtain the screening of the internal fields, nearly restoring the flat band condition. The emission energy in the high injection limit confirmed the quantum confinement in the wells.