FIGURE 5 XPS spectrum of the dark grey AlN powder sample
Although the Al2OC mesophase was identified by XRD in
Figure 3, the proof is still inadequate, because the intensity of the
Al2OC diffraction peaks is rather weak. Other effective
testing methods, e.g., XPS and TEM, were employed to determine the
existence of the Al2OC mesophase further. The whole XPS
spectrum of the dark grey AlN powder sample is shown in Figure 5,
containing the characteristic peaks of the Al, N, C, and O elements.
Among them, the C1S and O1S peaks are
strong, indicating high C and O concentrations of the powder sample.
During the XPS test, when the photoelectrons pass through the sample
surface, inelastic collision occurs, resulting in energy loss. As a
result, an accompanying peak exists on the spectrum, leading to the
deviation of the peaks of the neighboring elements (Figure 5).