Extended Data Fig. 6: Comparison between EDL repulsion and chemical etching: differences in detaching rate and etching rate.

a, Controlled experiment comparing the differences in detaching rate through EDL force versus chemical etching. The two identical PMMA spin-coated SiO₂/Si substrates are put into ammonia solution (32 wt%, room temperature) and hot KOH (1 mol l⁻¹, 70 °C). The temperature and concentration of KOH are chosen at the fastest detaching rate (see e). The detachment happens much faster in ammonia solution than in KOH. b, The SiO₂ thickness after being immersed in concentrated ammonia solution for an extended amount of time. The thickness is measured using ellipsometry. The error bars come from several ellipsometry measurements of the same piece of substrate. No observable change of thickness is found even after 100 h immersion, indicating no etching effect through EDL transfer. c, The etching rate of SiO₂ as a function of ammonia and KOH concentration. The etching rate for KOH is found from the literature^81,82, whereas that of the ammonia is measured by ourselves. d, The detaching rate of vdW materials from substrates as a function of ammonia and KOH concentration. e, The detaching rate of vdW materials from substrate as a function of KOH concentration and temperature. Both the z axis and colour bar show the value of detaching rate. The highest detaching rate is found to be approximately 0.1 mm s⁻¹ when the KOH concentration is about 1 mol l⁻¹ and the temperature is roughly 70 °C.