Tensile measurement of single crystal gallium nitride nanowires on MEMS test stages

This paper reports direct tensile tests on n-type (Si-doped) gallium nitride single crystal nanowires1 that were grown by nitrogen plasma-assisted molecular beam epitaxy and which are essentially free of defects and residual strain. Nanowires were integrated with actuated, active microelectromechanical (MEMS) devices using dielectrophoresis-driven self-assembly and platinum-carbon clamps created using a gallium focused ion beam. For one nanowire, failure strain of 0.042 ± 0.011 was found. Most nanowire specimens appeared to demonstrate tensile strength in the range of 4.0 ± 1.7 GPa to 7.5 ± 3.4 GPa. Failure modes included clamp failure, transverse (nanowire c-plane) fractures, and insufficient force from the MEMS test actuator.