Luminescence properties or rare earth doped III-V and II-VI semiconductors

Two novel step impact optical devices have been proposed by H. J. Lozykowski, the step impact electroluminescence device (SIED) and the step photon amplifier converter (SPAC). The realization of the proposed devices requires systematic study of the optical properties of rare earth doped semiconductors. The experimental data is explained using a kinetics model of energy transfer from the host lattice to the localized core excited states of rare earth isoclectronic structured traps (REI-trap). The numerically simulated lun-finescence rise and decay times show a good general quantitative agreement with experimental data, over a wide range of generation rates. A new quenching mechanism of ytterbium luminescence involving Yb and Fe ions is proposed. Detailed experimental and theoretical studies of the electrolurninescence excitation mechanism of Yb3+ in InP are presented. The electroluminescence (EL) spectra and the kinetics of Yb implanted InP are investigated under pulsed and dc excitations at different temperatures. The plot of natural logarithm (In) of I versus V−1/2 indicates that the direct impact excitation mechanism is a dominant process. A systematic study of the effect of oxygen on ytterbium 4f-4f emission by coimplanting Yb and O into InP is performed. The PL spectra and kinetic processes of InP: Yb and InP: (Yb+O) are recorded as a function of temperature, excitation intensity and annealing temperature and duration. No luminescence was observed after oxygen co-implantation and that is because the exciton bound to a Yb_In-O_P complex center will not have sufficient energy to excite the core Yb 4f electrons. The photoluminescence spectra and kinetics of Nd- and Yb-implanted CdS were investigated as a function of excitation intensity and temperature. The ac electroluminescence of thulium doped ZnS embedded in boric acid matrix was investigated as a function of voltage, frequency and temperature. The plot of In(I) versus V−1/2 shows a straight line characteristic over many orders of emission intensity which indicates that the direct impact excitation mechanism is a dominant process.