NATURE OF IMPURITY-INDUCED UV LUMINESCENCE OF MGO CRYSTALS

The decay kinetics and spectra of luminescence after pulse excitation by 10 keV electrons of MgO crystals doped with Li, Al, and F are investigated. The decay of UV luminescence (5.3 to 6 eV) due to these impurities obeys the hyperbolic law: I ∼t−‐α, α = const. The luminescence spectra shift to the long wavelength side with time passed after the end of the excitation pulse. The results are interpreted in terms of transitions within interacting donor‐acceptor pairs. The deviation from the hyperbolic decay law is also observed. It is suggested that in both the crystals, MgO–Li, F and MgO–F, isolated F− ions, substituting for oxygen, may be regarded as donors. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA