Accession Number:

ADA179211

Title:

The Cathodoluminescence of Cleartran: A Novel Form of Polycrystalline ZnS.

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1986-12-01

Pagination or Media Count:

177.0

Abstract:

Cathodoluminescence studies were carried out between 10 and 300 K on CLEARTRAN, a form of chemical-vapor-deposited cvd ZnS subjected to high temperature and pressure post-deposition processing. The results of these studies were compared to and contrasted with the cathodoluminescence of cvd ZnS samples grown by Raytheon and CVD Inc., with high quality crystal platelets of ZnS, and with bulk-grown cubic phase single crystal ZnS grown by Eagle-Picher Co. X-ray diffraction and spark-source mass spectrometry revealed that CLEARTRAN was composed of high purity cubic phase crystals from 20 to 40 micrometers in size. The low temperature near band-edge luminescence of CLEARTRAN was sharper and more detailed than any previous reports of cubic phase ZnS. The intensity of near band-edge luminescence was unusually strong, generally eclipsing the familiar Cu-blue and -green and self-activated low-temperature SAL peaks of undoped ZnS. Direct observation of the recombination of the n1 gamma 6 - gamma 8 free exciton led to an assignment of 35 meV for the free exciton binding energy. Exciton binding energies and ionization energies were also determined for seven unknown donors. By comparison with previous reports in the literature, the CLEARTRAN samples were shown to contain a significant concentration of copper, aluminum, chlorine, manganese, and oxygen impurities and, with a smaller degree of confidence, iodine impurity and zinc vacancies.

Subject Categories:

  • Crystallography
  • Optics
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE