The absorption coefficient of low dimensional semiconductor systems: the photoluminescence of InGaN quantum dot

The free carrier absorption coefficient of a low dimensional semiconductor system is formulated, with inclusion of interparticle Coulomb interaction, perturbatively, considering the bubble diagrams summed up to infinite order, which accounts for the multisubband (Q2D or Q1D case) or multilevel (Q0D case) electronic structure for reduced dimensionality. The experimental photoluminescence spectrum of a quantum dot of InGaN is used to estimate indirectly, through the absorption coefficient, the length of the side of the cube, which seems to be the geometry of the dots obtained in recent experiments. The results are consistent with other, independent, measurements.