Luminescence of F and F/sup +/ centers in magnesium oxide

Journal Article · Mon May 15 04:00:00 EDT 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.10309· OSTI ID:6086190

Rosenblatt, G H; Rowe, M W; Williams, Jr, G P; Williams, R T; Chen, Y

Time-resolved spectra of luminescence from F and F/sup +/ centers in MgO excited at 248 nm are reported over 8 decades of time and intensity, from 20 ns to 2 s. The decay time of F and F/sup +/ luminescence has been measured at temperatures ranging from 90 to 573 K. The luminescence yield and spectra were studied as a function of excitation-power density at 248 nm over a span of 10 decades, from 1 mW/cm/sup 2/ to 38 MW/cm/sup 2/. Higher pump-power density favors F luminescence over F/sup +/ luminescence in thermochemically reduced crystals, and the luminescence yield saturates above about 50 kW/cm/sup 2/ of pump intensity. Transient absorption spectra were measured in the microsecond-to-seconds time range. The luminescence data show that the decay kinetics of excited F and F/sup +/ centers are dominated by ionization from the excited state and charge recapture from traps which include the H/sup -/ center in thermochemically reduced MgO. It is furthermore inferred that electrons are the charge carriers having primary influence on kinetics of both F and F/sup +/ centers. This implies that the F/sup +/ first-excited state lies close to the conduction-band edge. We confirm that excitation at 248 nm also causes release of valence holes, and propose a mechanism which may explain the hole release, the increase of the F-to-F/sup +/ intensity ratio with increasing pump intensity, and the saturation of luminescence with increasing pump intensity.

• Research Organization: Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109
• OSTI ID: 6086190
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:14; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COLOR CENTERS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
F CENTERS
FLUX DENSITY
HIGH TEMPERATURE
KINETICS
LOW TEMPERATURE
LUMINESCENCE
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MEDIUM TEMPERATURE
OXIDES
OXYGEN COMPOUNDS
PHOTOLUMINESCENCE
POINT DEFECTS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
VACANCIES