Accession Number:

ADA133951

Title:

Polarization Effects in the Luminescence of Cadmium Selenide Electrodes.

Descriptive Note:

Technical rept.,

Corporate Author:

WISCONSIN UNIV-MADISON DEPT OF CHEMISTRY

Report Date:

1983-09-29

Pagination or Media Count:

22.0

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 le 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

Subject Categories:

  • Radiation and Nuclear Chemistry
  • Electrical and Electronic Equipment
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE