William Angerer - Department of Physics and Astronomy - University ...

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Sellmeier constant
value
Al 4.081
Al 0.16980
A2 0.1361
A2 .3453
Table 4.2: Empirical constant for GaN Sell meier equation. The Ai parameters are
expressed in J.tm.
by a normalized Gaussian frequency distribution, i.e. equation (4.-12). \Ve performed
a least squares fit to the data with the index of refraction as the only free parameter.
Appendix F discusses our optimization methods. This method is used for all data
fitting in this thesis.
Fig. 4.7 displays transmission data and calculations for a 1.020 J.tm Ga);' film on
A1 2 0 3 . This measurement was repeated in ",0.1 eV increments from A = 370-900 nm.
vVe fitted the observed dispersion in the GaN index of refraction with a two term
Sellmeier equation
n{A) = (4.43)
The empirically determined constants for the Sell meier equation are displayed in
Table 4,2. This dispersion relationship holds for all of our GaN samples.
GaN, like sapphire, is a birefringent material. However, all calculations of the
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