Abstract
Hishikawa et al. [Jpn. J. Appl. Phys. 30 (1991) 1008] recently used transmission (T) and reflection (R) measurements on amorphous silicon films to show that interference-free absorption spectra (α) can be obtained by self-consistently solving T/(1-R). We show that if R is measured with the sample illuminated from the substrate-side T and R can be converted to T f and R f, the transmission and reflection of a film on a semi-infinite substrate. For weakly absorbing films this simplifies the data analysis considerably as α can be obtained from T f/(1-R f) without any iterative procedures.