Spectroscopic ellipsometry investigation of Ga1−xInxN/GaN single and double quantum well structures

We present the results of spectroscopic ellipsometry (SE) measurements of Ga1−xInxN/GaN single and double quantum well samples grown on (0001)-oriented sapphire substrates with varying well and barrier widths. The band-gap energies of Ga1−xInxN wells of the samples were estimated by an optical multilayer model analysis on the observed pseudodielectric constant spectra. The change of the band-gap energy with the well and barrier width can be explained by the quantum-confinement effect of the carriers in the well. The variation of the band-gap energy of the well with the barrier width is in good agreement with the result of theoretical calculations based on the periodic square-well potential model.