Absorption spectra calculated on the basis of the reflectance and transmittance measurements. The left axis shows long exponential tails in the absorption edge. The right axis shows curves used for estimating the band gap according to the Tauc formula. The blue-shift of the absorption edge may be observed with increasing rH.
Zatryb et al. Nanoscale Research Letters 2011 6:106 doi:10.1186/1556-276X-6-106