THE BEHAVIOR OF PURE AND K-BOMBARDMENT( IMPLANTED LIF SURFACES UNDER ELECTRON)

As detected by Auger electron spectroscopy (AES), the interaction of a pure (100) LiF surface with an electron beam induces a loss of fluori ne. Lithium atoms are oxidized in the vacuum ambient and the formation of lithium oxide Li2O has been characterized using electron energy lo ss spectroscopy (EELS) by typical structures at 18.6 and 10 eV. The lo ss of fluorine is associated with a decrease of the positive surface p otential. The cathodoluminescence (CL) emissions detected in the 250-9 00 nm wavelength range at 3.8, 3.1, 2.3 and 1.9 eV have been attribute d to F, F-3(+) and F-2 centers. A quite different behaviour, without l oss of fluorine, is observed for a LiF sample implanted with potassium K+ ions. This implanted sample appears to be more stable under electr on irradiation than pure LiF. Such a different behaviour may be explai ned by a decrease in the efficiency of energy transfer mechanisms conn ected to different space-charge effects.