Magnetoluminescence study of a two-dimensional electron gas confined in diluted-magnetic-semiconductor quantum wells

We have carried out a photoluminescence study of an $n$-type modulation-doped ${\mathrm{Z}\mathrm{n}\mathrm{S}\mathrm{e}/\mathrm{Z}\mathrm{n}}_{0.825}{\mathrm{Cd}}_{0.14}{\mathrm{Mn}}_{0.035}\mathrm{S}\mathrm{e}/\mathrm{Z}\mathrm{n}\mathrm{S}\mathrm{e}$ single quantum well structure (electron areal density $n_A=1.6\mathrm{}\times {10}^{12}{\mathrm{cm}}^{\mathrm{-}2}$) in magnetic fields up to 30 T. In the presence of a magnetic field, the broad emission band in the vicinity of the gap evolves into a series of discrete features. These are attributed to interband transitions of electrons occupying Landau levels to photogenerated holes. The Landau transitions associated with both electron spin states ${(m}_j=\pm \frac{1}{2})$ are clearly resolved due to the large electron and hole $g$ factors exhibited by the magnetic wells. An analysis of the Landau-level occupation as a function of magnetic field yields the electron concentration.