Radiative recombination of bound excitons with site transfer final state excitations in Cu-Doped ZnTe

Novel recombination lines are observed as electronic satellites to bound excitons (BE:s) in photoluminescence (PL) spectra of Cu-doped ZnTe, when the doping is sufficiently-strong (1017-1018 cm−3) that complex Cu-related defects dominate the BE spectra. These replica are observed at discrete energies in the range 90-170 meV below the PL lines caused by the direct recombination of the BE state. The strength of these satellites is typically 5-10% of the parent BE line, and has a similar width (~0,2 - 0,4 meV). Such satellites occur with BE recombination for acceptor BE:s (ABEis) as well as isoelectronic complex BE:s (IBE:s). They also occur in a similar way in resonant Raman scattering (RRS). Magnetooptical data at 10T reveal an extremely complicated Zeeman splitting pattern of these satellites. The collected experimental data from selective dyelaser excited luminescence (SPL) spectra and excitation spectra (PLE) together with RRS and Zeeman results, suggest a recombination model where the BE state is interacting with a neutral acceptor state on a different site,, In the recombination process final state electronic shake up excitations of the type 1s-2s are observed on acceptors which are interacting with the defect site carrying the initial state BE excitation.