Many-body effects in highly p-type modulation-doped ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum wells

Many-body effects have been optically investigated for modulation-doped quantum wells at high acceptor densities. The observed band-gap shrinkage, up to $\approx 20\hspace{0.5em}\mathrm{meV},$ is consistent with calculations based on the Hartree and random-phase approximations including the finite well width effect. A recombination near the Fermi edge with light-hole character is strikingly enhanced at high acceptor densities. An interpretation based on carrier-carrier interaction is proposed. Finally, the exciton is found to be quenched for hole densities higher than $\approx 2\times {10}^{12}\hspace{0.5em}{\mathrm{cm}}^{-2}.$