Luminescence and Electroluminescence Properties of Rare Earth Doped GaAs, InP and GaN.

This research report contains progress in studies of the photoluminescence, and cathodoluminescence of the rare earth doped wide bandgap semiconductors. Photoluminescence and cathodoluminescence of GaN layer grown by MOCVD on 0001 sapphire substrate, undoped and n-type Si doped from Cree, and EMCORE. Temperature dependence of the near bandgap emission and donor acceptor pairs were investigated under excitation by He-Cd laser 325nm, and an electron beam 5 KeV. The photoluminescence and cathodoluminescence spectra show a similar future. For all sample the PL lines we found a continuous decrease of the peak energy with increasing temperature following the shift of the bandgap. Photoluminescence of GaN implanted with phosphorus200KeV shows the broad luminescence bands near 2.98 eV and 2.88 eV, and must be associated with the presence of these impurities in the system. The energies indicate impurity levels about 0.52eV and 0.62 eV from the band edges. We also investigated the synthesis and growth of single crystals of GaN needle single crystals approx. 4 mm long and 10-30 micrometers in diameter was growth. The preliminary results of PL, CL and kinetics of ZnO doped with Dy, Er, Tm, and co-doped with Li, are promising, we obtained for the first time ever strong rare earth PL and CL emission at room temperature. The photoluminescence study of microcrystalline powders of GaN doped with Dy, Er, Tm, Nd, codoped with Li, and GaN implanted with Er, Tm, Nd, and co-implanted with oxygen are in progress. The PL kinetics of p-type GaAs Nd implanted and MOCVD grown crystals were studied under pulsed excitations. The study shows that the PL rise time depends on excitation intensity. It reflects an indirect excitation process of Nd ions.