Fig. 1

Schematic of CMUT molecule structure and preparation process of MMCs. a Molecular structure of CMUT. Gray represents carbon atom, yellow represents sulfur atom, blue represents nitrogen atom, and white represents hydrogen atom. b Schematic illustration of preparation of the MMCs. The semiconductor solution was dropped onto an OTS-treated SiO2/Si substrate, and then a top substrate was placed atop. Finally we obtained crystalline monolayer films on the top substrate after 24 h. c Large-area CMUT MMC up to centimeter size on SiO2/Si substrate. d Optical microscopy image and e corresponding AFM image of the MMC on BCB-treated SiO2/Si substrate