Directly revealing the electrical annealing of nanoscale conductive networks with solid spins

Complex electrical structures composed of nanomaterials are widely studied in the research of nanoelectronics. Characterizing the current distribution is important to understand the current conducting mechanism and optimize the device's design. In this work, we employed the nitrogen vacancy centers in diamond as quantum sensors to directly and noninvasively monitor currents in nanowire networks. The sub-micrometer magnetic field imaging was achieved by injecting microwave current into networks and detecting the magnetic resonate spins' population, revealing the internal current paths involved in electrical conduction during electrical annealing. The establishment, breakdown, and reform of current paths were imaged in detail, which are difficult to realize through conventional methods. The mechanism of resistance change and relocating of current pathways was subsequently analyzed. This work demonstrates that a diamond-based quantum microscope is a useful tool to unveil the nanoscale conducting properties of complex conductive networks and guide the design for potential applications.