Excitonic Effects on theE1andE1+Δ1Transitions in InAs

The metamorphism of critical points due to Coulomb interaction, predicted by the theory of Toyozawa, has been determined experimentally through a careful examination of the temperature dependence of the line shapes of the $E_1$ and $E_1+{\Delta }_1$ structure of InAs. Besides, it has been possible to determine the shift coefficient $\frac{\partial {\omega }_g}{\partial T}=-5.5\mathrm{}\times {10}^{-4\mathrm{}}$ eV/°K and the broadening parameter $\frac{\partial \Gamma }{\partial T}=+0.9\mathrm{}\times {10}^{-4\mathrm{}}$ eV/°K of the $E_1$ structure.