Amplitudes of the Lorentzian fit for the D and G band (left) as well as the ratio of the peak amplitudes I_D/I_G (right). For the ratios, a we show a boxplot with the minimum, maximum, and the first and third quartile of the values as edges of the box. The orange line represents the median, and the green line shows the mean of the values. The spot measured for sample 4 falling outside of the range is considered an outlier.