Accession Number : ADA133951

Title :   Polarization Effects in the Luminescence of Cadmium Selenide Electrodes.

Descriptive Note : Technical rept.,


Personal Author(s) : Streckert,Holger H ; Van Ryswyk,Hal ; Biagioni,Richard N ; Ellis,Arthur B

PDF Url : ADA133951

Report Date : 29 Sep 1983

Pagination or Media Count : 22

Abstract : Polarization properties of the emission from single-crystal, n-type CdSe samples have been examined. When excited with several ultrabond gap wavelengths, a-plates of n-CdSe (wurtzite structure) exhibit polarized photo-luminescence (PL) spectra consistent with the reported electronic structure of the solid. The spectra consist of two bands near the band gap energy (approximately 1.7 eV), assignable to transitions between the conduction band and a split valence band having its two highest-energy band edges separated by approximately 0.022 eV; the lower-energy band is preferentially polarized with E is perpendicular toc while the other band displays no polarization preference. Time-resolved PL data, obtained with 620-nm excitation from a N2-pulsed dye laser, were independent of polarization. Intensity-time curves yielded a decay time ( t sub l/e) of approximately 20 ns for both bands, providing evidence that the two emissive excited states are in thermal equilibrium. Emissive properties of n-CdSe, a-plate electrodes were also consistent with thermal equilibration. Polarized electroluminescence (EL) spectra, obtained using the solid as a dark cathode in aqueous peroxydisulfate electrolyte, closely resemble their PL counterparts, demonstrating attainment of similar excited-state populations in the two experiments. And when the semiconductor is used as the photoanode of a photoelectrochemical cell employing diselenide electrolyte, the two PL bands resulting from 514.5- or 632.8-nm excitation are quenched in parallel by the electric field present in the semiconductor. (Author)

Descriptors :   *Electrodes, *Cadmium selenides, *Luminescence, *Polarization, Photoluminescence, Electroluminescence, Emission spectra, Single crystals, N type semiconductors, Excitation, Band spectra, Energy bands, Transitions, Conduction bands, Valence bands, Decay, Time, Photoelectric cells(Semiconductor), Electrochemistry, Laser induced fluorescence, Experimental data, Quenching

Subject Categories : Radiation and Nuclear Chemistry
      Electrical and Electronic Equipment
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE