Accession Number : ADA325946
Title : Erbium Doped AlGaAs/GaAs Quantum Wells
Descriptive Note : Final rept. 1 Jun 95-31 Mar 97,
Corporate Author : ARIZONA UNIV TUCSON OPTICAL SCIENCES CENTER
Personal Author(s) : Khitrova, Galna ; Gibbs, Hyatt M.
PDF Url : ADA325946
Report Date : 02 JUN 1997
Pagination or Media Count : 37
Abstract : The possibility of enhancing the luminescence efficiency of Er ions embedded in a semiconductor was investigated by growing about forty erbium-doped InGaAs/GaAs and GaAs/AlGaAs multiple quantum well samples by molecular beam epitaxy. The idea was to enhance the semiconductor-to-erbium transfer when the quantum-well and erbium-ion transition energies are equal. Photoluminescence of Er ions and Er induced defects was studied at liquid helium and higher temperatures. A strong diffusion of erbium and interdiffusion of Ga and Al ions was observed, leading at high erbium concentrations to the degradation of the QW's and macroscopic average leveling of Er and Al concentrations over the whole grown structure. From high-resolution photoluminescence spectra the existence of three types of Er centers was deduced which differ by positions of fine structure lines, photoluminescence lifetimes, and temperature dependence. These centers cause three types of carrier traps with binding energies of 20, 50, and 400 meV. Evidence is given that carriers captured into these traps control the Auger excitation of Er ions assisted by multiphonon emission. Er luminescence associated with the 400 meV trap is still detectable at room temperature. This grant was terminated abruptly after 71% of the funding was received, purportedly for financial rather than scientific reason.
Descriptors : *SEMICONDUCTORS, *LIGHT SOURCES, *LUMINESCENCE, *RARE EARTH ELEMENTS, *ERBIUM, THERMAL PROPERTIES, CONTROL, EMISSION, IONS, DEGRADATION, HIGH TEMPERATURE, EXCITATION, QUANTUM THEORY, QUANTUM WELLS, GALLIUM ARSENIDES, ALUMINUM GALLIUM ARSENIDES, PHOTOLUMINESCENCE, LASERS, HIGH RESOLUTION, ROOM TEMPERATURE, SPECTRA, DEFECTS(MATERIALS), SAMPLING, DIFFUSION, DOPING, PHONONS, INDIUM, AUGERS, CONCENTRATION(CHEMISTRY), LIGHT EMITTING DIODES, TRAPS, LEVELING, LIQUID HELIUM, MOLECULAR BEAM EPITAXY.
Subject Categories : Inorganic Chemistry
Lasers and Masers
Distribution Statement : APPROVED FOR PUBLIC RELEASE