INFLUENCE OF COMPENSATION ON THE LUMINESCENCE OF NITROGEN-DOPED ZNSE EPILAYERS GROWN BY MOVPE

The luminescence of ZnSe grown by metalorganic vapour phase epitaxy an d doped by a DC nitrogen plasma is investigated. With increasing N-2 f lux the donor-acceptor pair (DAP) band continuously develops into a st ructureless band peaking at 2.62 eV for highest doping levels. This br oad band evolves back into a structured DAP band peaking at 2.698 eV w ith increasing excitation density. At high N concentrations and at lar ge degree of compensation potential fluctuations become important for the spatially indirect DAP recombination. These fluctuations can easil y be screened by optically excited carriers making the experimental co nditions decisive for luminescence spectra of strongly doped ZnSe:N sa mples.