Thumbnail
Access Restriction
Open

Author Lang, J. M. ♦ Dreger, Z. A. ♦ Drickamer, H. G.
Sponsorship USDOE
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CHEMISTRY ♦ ZINC SULFIDES ♦ PHOTOLUMINESCENCE ♦ THERMOLUMINESCENCE ♦ INORGANIC PHOSPHORS ♦ COPPER ADDITIONS ♦ CHLORINE ADDITIONS ♦ CRYSTAL DOPING ♦ PRESSURE DEPENDENCE ♦ VERY HIGH PRESSURE
Abstract The authors have measured the effect of pressure on the luminescence and thermoluminescence characteristics of three ZnS phosphors doped with Cu and Cl. The total dopant concentration varied in the ratio 1/1.5/2.5, but the Cl/Cu ratio was constant at {approximately}8/1. The excitation was via the 325-nm (3.82-eV) line of a He-Cd laser. The absorption edge of ZnS is at 3.67 eV at 1 atm and increases by 6.35 meV/kbar, so that at high pressure the excitation is to {open_quotes}deep levels{close_quotes} provided by the Cl. The emission consists of two peaks at 20,000 and 22,000 cm{sup {minus}1} assigned to emission from a Cl{sup {minus}} center to a Zn vacancy and a Cu{sup +} center, respectively. Both emission peaks increased in energy with pressure. The shifts could be explained in terms of the degree of pinning of donor and acceptor levels to the conduction and valence bands. The thermoluminescence data indicated an initial trap depth of 0.3 eV for all three samples. This trap depth increased with pressure at low pressures but leveled at 0.39, 0.46, and 0.54 eV for the high-, intermediate-, and low-concentration samples, respectively. The thermoluminescence intensity decreased by 2 orders of magnitude in 40 kbar. The behavior of the thermoluminescence could be explained largely by differences in the nature and behavior of the {open_quotes}deep levels{close_quotes} initially in the conduction band. 28 refs., 10 figs., 2 tabs.
ISSN 00223654
Educational Use Research
Learning Resource Type Article
Publisher Date 1992-01-09
Publisher Place United States
Journal Journal of Physical Chemistry
Volume Number 96
Issue Number 1


Open content in new tab

   Open content in new tab