Variation of the wave function localization on the monolayer scale in GaSb quantum wells probed by magnetoluminescence

The wave-function localization on a single-monolayer length scale is studied by magnetophotoluminescence in GaSb quantum wells of thickness ranging between 5 and 40 ML. The excitonic effects are found to be important only in the low-field range (B(2 T), whereas free-carrier localization dominates at higher field values. Variational calculations of the excitonic transverse extension provide a quantitative description of the experimental data. The high sensitivity of the magnetoluminescence to the modifications of the wave function, even on the scale of a single monolayer, has been used to deduce experimentally the dependence of the effective reduced mass on the well width.