Fig. 4

∆p and ∆u values obtained by device absorbance fit vs. active layer thickness. The error bar in the x-axis represents the statistical standard deviation ±5 nm of the thickness determined by the profilometer. The error bar in the y-axis represents the statistical standard deviation of the possible fitting values. a Comparison of ∆p extracted from device absorbance fit vs. thickness between reflection mode and transmission mode. b Comparison of ∆u extracted from device absorbance fit vs. thickness between reflection mode and transmission mode