Exciton emission in Cd1-Mn Te(x ≅ 1%) grown by molecular beam epitaxy

Epitaxial Cd1-xMnxTe (x ≅ 1%) layers have been grown on a CdTe buffer layer on a GaAs (100) substrate, using molecular beam epitaxy (MBE). A comparison of the superimposed photoluminescence (PL) spectra in Cd1-xMnxTe and CdTe, observed by adjusting the thickness of the Cd1-xMnxTe layer, has made it easier to assign the excitonic origins of the Cd1-xMnxTe. A spectral-decomposition analysis has revealed that the free exciton emission is dominant in Cd1-xMnxTe grown at 350°C. This is in contrast to previous work where excitons bound to neutral acceptors are dominant in Cd1-xMnxTe at concentrations x less than 5%. A temporal energy shift of exciton emission is also observed in time-resolved measurements with and without an external magnetic field. The results are discussed in relation to magnetic polaron formation and the exciton localization effect arising from compositional inhomogeneity.