LUMINESCENCE PROPERTIES OF RARE EARTH DOPED II-IV AND III-V SEMICONDUCTORS

Two novel step impact optical devices have been proposed by H. J. Lozykowski [1], the step impact electroluminescence device (SIED) and the step photon amplifier converter (SPAC). The devices are multilayered heterojunction structures in which the acceleration and collision excitation processes are spatially separated and thereby permit independent optimization of each function in different materials. In the collision excitation region, the quasi-ballistic electrons excite the rare earth ions by direct impact. Emission from the rare earth ions with transition energy smaller than the semiconductor's band gap can be generated. The realization of the proposed devices requires systematic study of the optical properties of rare earth doped semiconductors, which has been the objective of this research. The basic luminescence properties of rare earth doped semiconductors, in particular InP:Yb were studied. Information are reported about the excitation and energy transfer and other related mechanisms by means of photoluminescence and electroluminescence spectra, time-resolved spectra, excitation spectra, the kinetics of photoluminescence and electroluminescence. In this research, the experimental results are compared to the theoretical kinetic model for InP:Yb, which was developed by H. J. Lozykowski, of the energy transfer from the host lattice to the localized core excited states of rare earth isoelectronic structured trap. Such model, though it was based on information derived from the investigation of the luminescence properties of Yb-doped InP, could be applied to other rare earth ions. The luminescence properties of other rare earth doped II-VI semiconductors such as, CdS:Yb, CdS:Nd, and ZnS:Tm, are investigated and reported.