Integrated Resonant Cantilever for Characterizing Molybdenum Oxide Thermal Decomposition

We performed thermogravimetric analysis (TGA) on the molybdenum oxide$\left(\text{MoO}_{3}\right)$crystals using a MEMS resonant cantilever integrated with resonant excitation, readout resistors, and a microheater. Compared with the milligram-level sample consumption of conventional thermogravimetric analysis, this technique offers ultrahigh mass resolution, enabling thermal decomposition characterization of tiny$\text{MoO}_{3}$crystals. By conducting cantilever-TGA on tiny$\text{MoO}_{3}$crystals and comparing the results from bulk using conventional-TGA, differences in their decomposition processes are observed: conventional TGA indicates that bulk$\text{MoO}_{3}$decomposes at approximately 810° C and 960° C, whereas the flake samples decompose around 180° C and 440° C. These two stages of mass loss may be attributed to the formation of molybdenum vacancies and the sublimation of$\text{MoO}_{3}$, respectively. The integrated resonant cantilevers hold promise for a better understanding of the thermal stability of nanomaterials.