We report a detailed compositional analysis of InxGa1-xN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition. Depth profiles of the InN fraction, x, in the MQWs were determined from grazing incidence Rutherford backscattering spectroscopy (RBS) analysis. Simulation of the RBS spectra provides precise estimations of individual well compositions, thickness, and the extent of In/Ga intermixing. It is ascertained that intermixing, and In segregation to the GaN cap layer, strongly increase with the value of x in the wells and with the number of periods in the MQW stack. Deleterious effects of intermixing on the spectral properties are apparent when comparing the photoluminescence spectra of two MQW structures with 8 and 18 wells, grown under the same nominal conditions.
- quantum wells
- Rutherford backscattering