Raman scattering from electrons bound to shallow donors in $\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}-{\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum-well structures

Transitions involving donor states were observed in resonant Raman scattering experiments on Si-doped $\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}-{\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ multiple quantum wells. The electronic scattering gradually transforms into photoluminescence as the exciting energy is tuned across the resonance. The largest contribution in the spectra is associated with $1S\to 2S$ transitions of donors near the center of the wells. The experimental results show good agreement with recent calculations.