Strain sensing with sub-micron sized Al-AlOx-Al tunnel junctions

TL;DR

This paper presents a novel strain sensing technique using sub-micron Al-AlOx-Al tunnel junctions on silicon nitride membranes, achieving high sensitivity to local static strain variations with a gauge factor up to 37.

Contribution

The study introduces a new method for local strain measurement employing metallic tunnel junctions with high gauge factors on nanostructured membranes.

Findings

Achieved a gauge factor of up to 37.

Demonstrated static strain detection down to 10^{-7}.

Validated the method's sensitivity for nanostructure strain sensing.

Abstract

We demonstrate a local strain sensing method for nanostructures based on metallic Al tunnel junctions with AlOx barriers. The junctions were fabricated on top of a thin silicon nitride membrane, which was actuated with an AFM tip attached to a stiff cantilever. A large relative change in the tunneling resistance in response to the applied strain (gauge factor) was observed, up to a value 37. This facilitates local static strain variation measurements down to ~10^{-7}.