Resonant distance spectroscopic microwave impedance microscopy

Abstract

Microwave impedance microscopy (MIM) is a powerful technique for mapping electronic properties at the nanoscale. The current state-of-the-art, dynamic mode MIM uses lock-in detection at the probe's mechanical resonance to obtain drift-free measurements with high spatial resolution. However, this approach inherently discards valuable information encoded in the nonlinear tip–sample admittance–distance relations. Here, we introduce resonant distance spectroscopic MIM (Rz-MIM), a modality that combines wideband MIM electronics, high-speed data acquisition, and on-the-fly processing to capture complete admittance–distance spectroscopy curves at twice the mechanical resonance frequency. The resulting hyperspectral dataset encodes significantly richer information than conventional approaches and enables more quantitative determination of underlying material properties. It also enables post-processing techniques such as retrospective enhancement of spatial resolution. Our results establish Rz-MIM as a high-throughput platform for more quantitative, hyperspectral nanoelectronic imaging.