Figure 3: SiNR mechanical sensors of different sensitivities and detection ranges.

(a) Sequential images of SiNR strain gauges (top frames) under different applied strains (0, 15 and 30%) and corresponding FEA results (bottom frames). Scale bar, 1 mm. (b) The resistance changes for different curvatures of SiNR, depending on applied strain (left) and temporal resistance changes of different curvature of SiNR under cyclical stretching (right). (c) Regionally mapped per cent resistance changes, measured by site-specifically designed strain gauge arrays (S1 for minimal stretch region and S6 for large stretch region). Mapped regions are indicated with red dotted box for four different motions. Scale bar, 2 cm. (d) Schematics showing the working principle of the SiNR pressure sensor with a cavity (top left) compared with the SiNR pressure sensor without a cavity (bottom left), scanning electron microscope images of the device's cross-section with a cavity (top middle) and without one (bottom middle) and FEA results (top right; bottom right). Scale bar, 500 nm. (e) The resistance changes of a pressure sensor with a cavity (black) and without a cavity (red) with respect to the applied pressure for different design of the SiNR (S1: graph on the left, S6: graph on the right). (f) Regionally mapped per cent resistance changes measured by pressure sensor array of S6 for gradually increasing pressure. Princi., principle; Stretch., stretching.