Strain-Induced Electrical Conductivity in Diamond Nanowires

At the nanoscale, a highly insulating ultrawide-bandgap diamond turns from a hard but brittle bulk solid into highly elastic rods and wires. It has been predicted that such an elasticity change would be sufficient to increase conductivity and narrow the bandgap, enabling metallization of diamond at the nanoscale, making it suitable for nanoscale applications. In this work, we experimentally demonstrate that applying a mechanical load by using an atomic force microscopy cantilever increases conductivity in diamond nanowires. Mechanical properties are tested via a micromanipulator inside the scanning electron microscope, and nanowires show a high bending angle of 39°, before fracture, indicating their elasticity. Furthermore, finite element method simulations suggest that the strain in the central region of the nanowire with maximum vertical displacement is sufficient for metallization in nanowires. Our findings provide direct evidence of the strain-induced conductance in diamond nanowires, pivotal for durable quantum electronics and biomedical applications.