Band-gap renormalization of optically excited semiconductor quantum wells

The band-gap renormalization of optically excited semiconductor quantum wells due to exchange-correlation effects in the electron-hole system is studied here. The first-order self-energies for this two-component electron-hole plasma are calculated exactly within the random-phase approximation. All intersubband interactions are included fully, and they are found to make significant contributions to the self-energies and to their subband dependences. Particular attention is paid to the subband dependence of the band-gap renormalization. These calculations are made for realistic systems with finite well widths, finite barrier heights, and finite temperatures. The results are compared with recent experimental data for Inₓ{Ga}_{1{{-}}x}$As/InP and GaAs/${Ga}_{1{{-}}x}AlₓAs quantum wells.