Figure 3. a) Schematic of a SAXS transmission geometry, with q i and q f denoting the incident and scattered beam wave vector, respectively. b) SEM and STEM cross-sectional images; reproduced with permission. [17] Copyright 2020, Wiley-VCH and c) SAXS profiles for U-CIGS, BK-CIGS, and SK-CIGS films. The dotted arrows denote the peak positions of the SAXS profiles at which the domain spacing is estimated. Reproduced with permission. [17]