Wrinkling surface of mono-layered thin film derived by using trifluoroacetate solution

Wrinkling morphology could be utilized in various sensors because of its large specific surface area depending on the amplitude (A) of the wrinkles. The amplitude was proportional to film thickness (h) in the traditional wrinkles fabrication processes, and it is inefficient to increase the wrinkle amplitude by adjusting the film thickness. Hence, it is very necessary to propose a method that can significantly increase the wrinkle amplitude by changing the film thickness. In this study, the wrinkling morphology of mono-layered thin films prepared via chemical solution deposition on rigid substrates was investigated. By using the solution with various cation concentration, thin film samples were fabricated with h ranging from 474 to 1405 nm. A rapid pyrolysis with ramping rate of 5 °C \({\min }^{-1}\) was applied to obtain the wrinkling morphologies, which were characterized by white-light interferometer and scanning electron microscope. Amplitude values were calculated out of the height images by using two-dimensional fast Fourier transform. The approximate relationship of amplitude with film thickness A ∝ h³ was found. Compared to the traditional multi-layered architecture, wrinkling film was fabricated by depositing a mono-layered thin film on a rigid substrate in this work, which is simple and low-costing. Amplitude A could be more sensitive to h, which might be beneficial for response sensitivity in various fields. The wrinkling mechanism of chemical solution deposited thin films during rapid pyrolysis was discussed based on the assumption of gas accumulation in the precursor film, and a model based on the accumulation of byproduct gas during pyrolysis was proposed to interpret the relationships.