Reflectance study of Al_(0.4)Ga_(0.6)Sb/GaSb single quantum wells

We report a reflectance study from 0.6 to 1.5 eV and at temperatures from 6 to 300 K on a series of Al0.4Ga0.6Sb/GaSb single quantum wells with different well thicknesses (tw = 4, 6, 8 and 11.7 nm), grown by Molecular beam Epitaxy on (001) GaSb substrates. R spectra show clear evidence of the structures associated to the allowed transitions from the n-th heavy- and light-hole to the n-th conduction subband level for n = 1, 2. The comparison between the experimental transition energies and those calculated in the framework of the envelope-function scheme showed a good agreement, thus confirming the reliability of the values for relevant QW parameters as band-offset, effective masses and band non-parabolicity.