Figure 1.

a) Illustration showing the growth of ultrathin carbon nitride film by CVD onto surfaces. b) Idealized molecular structure of the g‐C₃N₄ film on a substrate. c) Quartz substrate before and after film polymerization. Scale bar: 1 cm. d) SEM images of a scratch in an otherwise continuous carbon nitride film on a silicon wafer substrate. Scale bar: 10 μm. e) Mean roughness of the film as determined by AFM is about 0.51 nm. Scale bar: 1 μm. f) Typical AFM height image of the film and the corresponding height profile over a scratch showing a thickness of about 10 nm. Scale bar: 1 μm. g) High‐resolution TEM of a free standing film indicating at least local crystallinity but full orientation with layers parallel to the surface. Scale bar: 10 nm. h) EDX analysis of carbon nitride film. Scale bar: 10 μm. i) FTIR of blank glass substrate, g‐C₃N₄ film on glass, and g‐C₃N₄ powder. j) XRD of blank glass substrate, g‐C₃N₄ film on glass, g‐C₃N₄ powder, and difference value (D‐value) between g‐C₃N₄ film on glass and blank glass substrate.