fig4

Figure 4. (A) XRD patterns of the ball-milled PV nano-Si with various milling times (1, 3 and 9 h) and (B-F) SEM images: (B) Purified PV Si (before ball milling); (C) PV nano-Si-1h; (D) PV nano-Si-3h with inset TEM bright field image; (E) PV nano-Si-9h; and (F) Commercial nano-Si (Sigma-Aldrich).