Tellurite And Fluorotellurite Glasses For Active And Passive

7. Surface properties; MDO 288
sample (with a residual standard deviation between the XPS data and Gaussian / Lorentz
fit typically < 1.61).
Table (7.8) summarises the quantitative analysis from the high resolution scans, and
for comparison, the actual atomic % batched and theoretical peak positions from the
NIST XPS database.
Table (7.8): Quantitative analysis from high resolution XPS scans of polished glass
MOF001_v (65TeO2-10Na2O-25ZnF2 mol. %), and theoretical peak positions and atomic
% batched.
XPS peak Theoretical High resolution XPS scan
Peak / eV At. % Peak / eV At. % Wt. %
Te 3d5/2 576.2 21.67 576.3 16.29 57.35
O 1s 530.4 46.67 532.3 71.48 31.55
Na 1s 1072.5 6.67 1071.7 2.90 1.84
Zn 2p3/2 1022.5 8.33 1022.0 3.41 6.15
F 1s 684.8 16.67 684.6 5.92 3.11
It can be seen by comparing table (7.8) with table (7.7) that the surface composition of
the glass was significantly different to the bulk (which can be approximately represented
by the cleaved sample analysis in table (7.7)). The oxygen level at the surface was around
25 at. % more than the as-batched composition (71 and 47 at. % respectively), and the
fluorine level around 11 at. % less (6 and 17 at. % respectively), which corresponds to
around 67 % less fluorine than in the bulk glass.
Fig. (7.22) summarises the atomic % composition of the batched (i.e. theoretical),
cleaved, and polished glass surface, of composition MOF001_v (65TeO2-10Na2O-
25ZnF2 mol. %), which was melted for 2 hours with fluorinated ZnF2.