STRAIN SPLITTING OF NITROGEN ACCEPTOR LEVELS IN ZNSE

We report on the experimental and theoretical study of the strain spli tting of nitrogen acceptor levels in epitaxially grown ZnSe on GaAs su bstrate, The crystal strain is due to the different lattice constants and thermal expansion coefficients and is determined by x-ray diffract ometry. The binding energies of the acceptor ground and excited states have been determined by temperature-dependent and resonant photolumin escence measurements involving two-hob transitions for three different ly strained layers. A consistent theoretical description of the experi mental data is given in terms of the model of Baldereschi and Lipari, augmented by the Bir-Pikus Hamiltonian to account for the strain split ting of the valence-band edge. An empirical ansatz for the central-cel l correction is used in order to reproduce the chemical shift of the n itrogen acceptor.