Ultra-low dissipation patterned silicon nanowire arrays for scanning probe microscopy.

In recent years, self-assembled semiconductor nanowires have been successfully used as ultrasensitive cantilevers in a number of unique scanning probe microscopy (SPM) settings. We describe the fabrication of ultralow dissipation patterned silicon nanowire (SiNW) arrays optimized for scanning probe applications. Our fabrication process produces ultrahigh aspect ratio vertical SiNWs that exhibit exceptional force sensitivity. The highest sensitivity SiNWs have thermomechanical noise-limited force sensitivity of 9.7 +/- 0.4 aN/root Hz at room temperature and 500 +/- 20 zN/root Hz at 4 K. To facilitate their use in SPM, the SiNWs are patterned within 7 mu m from the edge of the substrate, allowing convenient optical access for displacement detection.