Young's modulus and corresponding orientation in β-Ga_2O_3 thin films resolved by nanomechanical resonators

摘要

We report on the nondestructive measurement of Young's modulus of thin-film single crystal beta gallium oxide (β-Ga_2O_3) out of its nanoscale mechanical structures by measuring their fundamental mode resonance frequencies. From the measurements, we extract the Young's modulus in the (100) plane, E_Y.(100) = 261.4 ± 20.6 GPa, for β-Ga_2O_3 nanoflakes synthesized by low-pressure chemical vapor deposition (LPCVD), and in the [010] direction, E_Y.(101)= 245.8 ± 9.2 GPa, for β-Ga_2O_3 nanobelts mechanically cleaved from bulk β-Ga_2O_3 crystal grown by the edge-defined film-fed growth (EFG) method. The Young's moduli extracted directly on nanomechanical resonant device platforms are comparable to theoretical values from first-principle calculations and experimentally extracted values from bulk crystal. This study yields important quantitative nanomechanical properties of β-Ga_2O_3crystals and helps pave the way for further engineering of β-Ga_2O_3 micro/nanoelectromechanical systems (M/NEMS) and transducers.