Biaxial Micro-Mechanical Device (MMD) with Meta-Structure for In-Situ Mechanical Testing

Abstract Background Low-dimensional materials are crucial for next-generation electronic systems but their size-dependent mechanical properties demand precise in situ mechanical characterization. Conventional platforms such as push-to-pull (PTP) micromechanical devices are limited by high fabrication costs, poor load–displacement linearity, and restriction to uniaxial stretching. Objective This study aims to develop a novel and stable micro-mechanical device (MMD) device with excellent load–displacement linearity, utilizing cost-effective fabrication method, and to investigate the biaxial tensile behavior of low-dimensional materials. Methods We designed a MMD with a meta-structure of chiral patterns, fabricated using standard silicon wafers and wet etching, which reduces production costs and enables batch manufacturing, and did the uniaxial and biaxial tensile test. Results This design reduces stretching stress, enhancing stability, load–displacement linearity, and experimental repeatability. Uniaxial Scanning electron microscope (SEM) tensile tests confirmed no bulk rotation after 2000 nm displacement, while the gap of 3 μm was shown to be compatible with in situ tensile testing, and cyclic loading experiments validated repeatability. As a proof of concept, in situ tensile testing of ZnO nanowire revealed a strain of approximately 5%. Furthermore, a biaxial tensile MMD based on the meta-structure was demonstrated, with transverse and longitudinal displacements remaining nearly identical within 3 μm. Conclusion This MMD provides a cost-effective solution and tailorable platform for in situ mechanical characterization of low-dimensional materials, with the capability of biaxial stretching.