TiO2 samples for XPS analysis were prepared on degenerately doped n-Si substrates (Siltronix, <111>, 0.4-0.6 ohm cm resistivity, 500-550 μm thickness). Wafers were cleaned and etched prior to TiO2 deposition, as previously described. A Physical Electronics (PHI) Quantum 2000 X-Ray photoelectron Using the capacitances obtained from a CPE in the Voight EC and subsequently using the transformation equations has no effect on the values of the resistances obtained, when compared to fitting the data directly to the Maxwell circuit. The same can be said for the capacitance of silicon.