Photoluminescence excitation study of nitrogen-doped zinc selenide epilayers

Photoluminescence excitation (PLE) spectroscopy at liquid-helium temperatur e is used to study six ZnSe:N epilayers grown by molecular beam epitaxy. Th ese samples represent nitrogen-doping levels ranging from less than 10(17) to 3 x 10(19) cm(-3). The luminescence emission bands from the heavily dope d samples exhibit peak energies varying from 2.45 to 2.61 eV. The energy ra nge over which the PLE signal intensity decays and the energy difference be tween the onset of this decay and the PL peak energy are essentially the sa me for all the heavy-doped samples. A model is proposed to explain the PL a nd PLE results for a semiconductor in the presence of potential fluctuation s. (C) 1999 American Institute of Physics. [S0021-8979(99)01609-6].