Fig. 3

TEM analyses of the Sn₂S₃–SnO₂ thin film. a Low-magnification cross-sectional TEM image of the film. b HRTEM image taken from the inner region of the film (marked with 1 in a). The region corresponded to the region of Sn₂S₃ phase. c HRTEM image taken from the outer region of the film (marked with 2 in a). It shows that the SnO₂ phase distributed on the outer region of the Sn₂S₃ phase. d Cross-sectional EDS line-scan profiling spectra of Si, Sn, S, and O elements taken from the film (as shown with a red line in a)