Tunneling Barrier-Integrated Gold Nanofilms for Negative Strain Gauging with Near-Zero Energy Consumption.

Chae, Soosang; Choi, Wonjin; Lee, Su-Hyeong; Besford, Quinn A; Fery, Andreas · Nano Lett · 2025

basic_science · Level V

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Abstract

Wireless strain sensors with minimal power needs are essential for long-term monitoring in energy-limited environments. We present a soft tunneling barrier-integrated gold thin film for negative strain sensing with near-zero energy consumption. The device features a strain-induced transition from an insulating to a metallic state, increasing conductivity by 9 orders of magnitude under a controlled strain. It consists of Au-PDMS-Au nanofilm layers, where the Au structures are near the percolation threshold and the PDMS layer acts as a tunneling barrier. Under strain, thinning due to the Poisson effect lowers the barrier's potential height, enabling electron tunneling and forming an electrical path. With a standby power consumption of ∼10<sup>-5</sup> mW over 10<sup>6</sup> times lower than conventional sensors (∼12.5 mW), this device is ideal for real-time, long-term stationary structural monitoring in multiple locations.