Fluorine as a shallow acceptor in ZnSe

Fluorine-doped ZnSe epilayers were grown by metalorganic atomic layer epitaxy using a selective doping method and were characterized by photoluminescence spectrosopy. The photoluminescence spectrum of the fluorine-doped ZnSe epilayer exhibits two emission peaks when fluorine is supplied onto the Zn surface. The origin of these emission peaks is suggested to be due to the excitons bound to neutral fluorine atoms and the donor-to-fluorine acceptor emission. This is confirmed through the change in the energy positions of the emission peaks with the excitation intensity. These results suggest that fluorine is incorporated as an acceptor with an energy level of about 90 meV.