New Analysis of Direct Exciton Transitions: Application to GaP

A new analysis of direct exciton data is presented and applied to the $E_0$, $E_0+{\Delta }_0$ transitions in GaP. A curve-fitting procedure is used to compare both the discrete and continuum structure in the data with theoretical curves. Good agreement is obtained for the binding energies, broadening, strengths, and shapes. It is shown that the binding energy of $E_0$ is 11 ± 1 meV rather than the 5-6-meV value previously obtained from the conventional analysis.