“…For a-Si, films need to be <25 nm in thickness (Voyles, 2001). When FEM is used for higher Z materials, such as chalcogenides (Kwon et al, 2007; Lee et al, 2009; Darmawikarta et al, 2013) and amorphous metals (Stratton et al, 2004, 2005, 2006), multiple scattering effects need to be considered. When the scattering factor is independent of angle, the average number of scattering events n iswhere n is the number of scattering events, t the thickness, and Λ the total mean free path for all elastic scattering processes (Treacy & Gibson, 1993).…”