Figure 2
Measured and fitted XRR spectra of the HfO2/graphene/SiO2/Si structures with (a) ZnO and (b) Hf seed layers between HfO2 and graphene. For the Hf-seeded sample in (b), spectrum fitting was performed by assuming the seed layer as metallic Hf and HfO2. The insets of each figure represent the depth profiles of the electron density with respect to that of SiO2, which was extracted from the fitted curves. The inset figure of (b) was obtained from the best fitting result, assuming that the Hf seed layer is completely converted to HfO2. The simulated layer density and thickness values are also tabulated in Table 2.
