Fig. 2: PXRD patterns and SEM images.

a, Product A. b, Product B. Crystals with needle- and plate-like morphologies are observed in product A (Si/Ge = 10, (Si + Ge)/Al = 15). Uniform plate-like crystals are present in product B (Si/Ge = 5, (Si + Ge)/Al = 12.5). More details (original PXRD patterns and additional SEM images) of product A and product B are given in Supplementary Figs. 3 and 5, respectively.