Figure 4

3D nano-profiler imaging. 3D view (a): The electrode edges were smooth and sharp as can see in the image; Specification data (b): The height, area size and pitch of the fabricated sensor were visibly noted on the table; 2D view (c): The gap between the electrodes were fabricated according to the design dimensions.; Surface roughness (d) and waviness (e) based on the black line shown in 2D image.