MEMS Resonant Sensors for Characterizing Molybdenum Ditelluride Decomposition

We demonstrate the measurement of thermal decomposition of semiconducting molybdenum ditelluride (MoTe2) crystals using MEMS resonant sensors. The MEMS resonator comprises resonance excitation and detection resistors for mass sensing, and a microheater for sample heating. The sensor exhibits ultrahigh mass resolution, enabling the characterization of MoTe2 decomposition with a sample amount of less than 1ng. Using the MEMS resonant sensors, we perform thermogravimetric analysis on 2H-MoTe2 crystals in air and observe two significant mass loss steps at ~400°C and 430°C, indicating the oxide (TeOx, MoOx) decomposition. We then compare the TGA curve in air with that in N2, which shows a significant mass loss at !~730°C, suggesting the decomposition of 2H-MoTe2 crystal at a much higher temperature. Overall, the mass change stages measured by the MEMS resonant sensors bring a better understanding of the thermal properties of 2H-MoTe2 crystals.