-SiO2@ON/glass was coated with poly(methyl methacrylate) (950 PMMA C4, Micro Chem, 2 mL) by spin coating (500 rpm for 5 s, 1,000 rpm for 5 s, 2,000 rpm for 5 s, 1,000 rpm for 5 s, SP-7200GT spin coater, Intec systems). The plate was cut into 4 pieces of 1.5 × 2.5 cm2 area (Refer to Figure S3), and then added to 5% HF solution (100 mL). In the first 1 min, the glass plate was detached from S-SiO2@ON/glass and removed. The S-SiO2@ON was further etched for 2 h. Caution: HF solution is extremely dangerous to be inhaled and touch. Thus, it should be handled with extreme caution and specific gloves in a good hood.…