Narrow-line excitonic photoluminescence in ${\mathrm{G}\mathrm{a}\mathrm{N}/\mathrm{A}\mathrm{l}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}$ quantum well structures with inversion domains

Microphotoluminescence studies reveal strong and narrow lines of $\sim 1-\mathrm{meV}$ minimal width in ${\mathrm{G}\mathrm{a}\mathrm{N}/\mathrm{A}\mathrm{l}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}$ quantum well (QW) structures having inversion domains (IDs). These narrow lines coexist in the spectra with broad (10–15 meV) peaks. The features of both kinds are characteristic for intersections of the IDs with QWs, which provide either three- or one-dimensional carrier confinement, depending on both the ID diameter and well width.