Graphene-Based Tunneling Strain Sensors: A Mechanism Study

Strain sensors that are based on graphene's tunneling effect have attracted broad interest in recent years, but their sensing mechanism remains to be further explored. We designed a strain sensor formed by only two layers of graphene islands, which exhibits a considerably high sensitivity with the highest gauge factor (GF) of 8538.5. Detailed experimental evidence using isotope labeling-assisted Raman spectroscopy indicates that such performance results from the reduced overlapping areas by the island sliding rather than by the deformation of the islands. Finite element method simulation was conducted to analyze the detailed sensing process, and a theoretical equation for the sensitivity was established to fit the experimental data. We believe that our results can offer fundamental support for tunneling-based strain sensors using two-dimensional materials and help further optimize their structures and performances.