DYE-LASER SELECTIVE SPECTROSCOPY IN BULK-GROWN INDIUM-PHOSPHIDE

Donor-acceptor selective luminescence and luminescence excitation spectra of a specially refined InP crystal grown by the liquid encapsulated Czochralski technique are compared with results recently reported (Dean et al., 1979) for the common contaminant Zn. Carbon is the dominant acceptor in the new crystal with EA approximately 41.5 meV compared with (EA) Zn=48 meV. These excitation techniques provided by a tuneable dye laser provide clean resolution of several acceptor internal excitations whose transition energies are characteristic of the acceptor species, even though no useful information is available from the bound exciton spectra due to excessive spectral broadening. Transitions to two clearly resolved p states of the C acceptor yield p-state binding energies identical to those for the Zn acceptor while the binding energy of a single s state is a little less as expected. The high discrimination of the technique permits the probable identification of a second minor acceptor species as Zn.