Fig. 1
From: Porous amorphous silicon film anodes for high-capacity and stable all-solid-state lithium batteries
Microscopy images of as-prepared amorphous Si films. a–d Field-emission scanning electron microscopy (FE-SEM) images of surface of a, b non-porous and c, d porous films. The scale bar for (a, c) represents 1 µm. The scale bar for (b, d) represents 100 nm. e–h FE-SEM cross-sectional images of e, f non-porous and g, h porous films. The cross-sectional FE-SEM images were obtained at a tilt angle of 60°, and thus the scale bars in the images are only applicable to the horizontal direction. The upper and lower dashed white lines in (f) and (h) indicate the surfaces of amorphous Si films and stainless-steel substrates, respectively. The scale bar for (e, g) represents 10 µm. The scale bar for (f, h) represents 500 nm. i–l Annular dark-field scanning transmission electron microscopy (ADF-STEM) cross-sectional images of i, j non-porous and k, l porous films. The scale bar for (i, k) represents 2 µm. The scale bar for (j, l) represents 500 nm. The microscopy images acquired using higher magnifications for the low-magnification images of (a), (c), (e), (g), (i) and (k) are presented in (b), (d), (f), (h) and (j), respectively. The non-porous and porous Si films were prepared by magnetron sputtering with Ar at 0.4 Pa and He at 5 Pa, respectively. The carbon top layers onto the Si films in the cross-sectional images are protection layers against damage from focused ion beam (FIB). The areal mass loadings and the thicknesses of the observed films are indicated below the corresponding images; the surface and cross-sectional FE-SEM images were taken from the same samples and the values are indicated below the cross-sectional images
