BIEXCITON EMISSION FROM THICK ZNSE EPILAYER GROWN BY MOLECULAR-BEAM EPITAXY

Photoemission under high photoexcitation in thick ZnSe epilayer grown by molecular beam epitaxy (MBE) has been investigated using time-resol ved photoluminescence spectroscopy. The presence of biexcitons is demo nstrated under picosecond pulsed excitation as biexciton emission is o bserved 4 meV below the free exciton emission. The rise time of the bi exciton emission follows the rise time of the free exciton and decays with a single exponential form with shorter lifetime than the free exc iton. This clear observation of biexciton luminescence in MBE grown Zn Se epilayer, suggests that spontaneous emission commonly observed at l asing threshold under optical pumping at low temperatures is due to bi exciton recombination. (C) 1998 American Institute of Physics.