Wet-Chemical Surface Texturing of Sputter-Deposited ZnO:Al Films as Front Electrode for Thin-Film Silicon Solar Cells

Figure 4

SEM micrographs of AZO films textured with the two-step sequences (left = HF/HCl, right = HCl/HF). (Left) 1% HF etching for 20 s and then 0.5% HCl etching for (a) 0 s, (b) 10 s, (c) 20 s, (d) 30 s, and (e) 40 s. (Right) 0.5% HCl etching for 20 s and then 1% HF etching for (f) 0 s, (g) 10 s, (h) 20 s, (i) 30 s, and (j) 40 s. During the measurements the samples were tilted by 60° and the images were recorded with a magnification of 25000.