Kl. Wang et al., THE REACTION OF CLEAN LI SURFACES WITH SMALL MOLECULES IN ULTRAHIGH-VACUUM .1. DIOXYGEN, Journal of the Electrochemical Society, 143(2), 1996, pp. 422-428
The creation of clean Li surfaces by vapor deposition and their subseq
uent interaction with oxygen have been studied by a combination of ell
ipsometry and Auger electron spectroscopy in ultrahigh vacuum. The ell
ipsometric parameters Delta and Psi for Li thin films vapor-deposited
on a Ni substrate were monotonic functions of the film thickness, and
in reasonable agreement with theoretical values calculated for dense (
nonporous) films. The clean Li surface is very reactive sticking coeff
icient of unity at the initial stage of oxidation at 5 x 10(-8) Torr O
-2. Oxidation of the entire film (75 Angstrom maximum) into Li2O proce
eded with an approximately unit reaction probability. A model of oxida
tion with in-plane contraction of the oxide film (continuously exposin
g fresh Li) is proposed to explain both the high rate of reaction and
the observed variation of Delta and Psi with time of exposure to O-2.