5. High resolution XPS spectra (both are cartoons, not real spectra) of a silicon wafer are shown below. Spectrum b was taken after heating in air at 500 deg. C. for 1 hr. Interpret the peaks. What change occurred between a and b? (10 points) b I u 105 104 103 101 100 99 98 97 102 Binding Energy (V) u u a I n 105 104 103 102 101 99 98 97 Binding Energy (V)