Biexcitons, impurity transitions, and electron–hole plasma in highly excited II–VI compounds?

To determine the origin of the so‐called M‐ and P‐emission bands, observed in highly excited II–VI compounds at low temperature, CdS is investigated at 5 K by means of excitation spectroscopy. The results are discussed in terms of inelastic scattering processes, biexcitons, impurity transitions, and electron–hole plasma (EHP), including in the discussion also results published by other authors. It is shown that in II–VI compounds the high‐excitation luminescence is mainly due to inelastic scattering processes and to impurity transitions at low temperature and that it is only to a smaller extent caused by EHP and biexciton decay.