上海科技大学知识管理系统

We report on thermogravimetric analysis (TGA) of semiconducting molybdenum ditelluride (MoTe2) layered flake using a MEMS resonant cantilever sensor (‘cantilever-TGA’). The sensor integrates resonance excitation/excitation resistors for mass sensing and a microheater for sample heating. Thanks to the picogram-level mass resolution, only one piece of MoTe2 flake (~150pg) is adequate for characterizing the thermal stability, much smaller than those required by conventional TGA (~mg). We characterize the MoTe2 flake in 2H-phase in nitrogen (N2) using cantilever-TGA, which shows apparent 2-stage mass losses at ~240 and 730°C, and the flake decomposes completely until 800 °C. We then compare the cantilever-TGA curve with that obtained using conventional TGA, which shows 2-stage mass losses at ~510 and 950°C and the sample decomposes only 30% until 1000°C. The 2-stage mass loss could be attributed to the Te vacancy formation and a primary decomposition stage of MoTe2, which occur at much lower temperatures for MoTe2 flake than those for MoTe2 bulk crystal. Our results can bring new knowledge about the thermal stability of 2D flakes with ultrahigh mass resolution and at low cost.