nanomesh sectional geometries varied from vertically erected nanobelts or nanowires depending on the size of the photomask patterns and the UV dose in the second photolithography process as shown in Figure 3e,f. The suspended carbon nanomeshes are designed to align obliquely to the bulk carbon post edges so that each junction, where four short carbon nanowires intersect, is supported evenly by the four nanowires. This robust mesh design avoids stiction between neighboring wires due to surface tension during development and breakage of the mesh structures during SHP099 molecular weight pyrolysis, and as a result, the nanowires can be spaced with a small gap. Figure 3 Scanning electron microscopy images of various types of suspended carbon nanomeshes. (a) A football-shape, (b,c) diamond shapes, (d) a hexagonal shape, (e) a vertically erected nanobelt type, (f) a nanowire type. The
CDK inhibitor microstructure of the pyrolyzed carbon structures Tucidinostat ic50 was analyzed using HRTEM and Raman spectroscopy. Figure 4a shows a HRTEM image at the edge of an approximately 190-nm-diameter carbon nanowire. Because the diameter of the suspended carbon nanowire is too large for electrons to be transmitted across the nanowire center, only the edge of a carbon nanowire as-made could be clearly observed in TEM (Figure 4a). The nature of the carbon nanowire is predominantly disordered but shows some short-range ordered nanostructures. The nature of the microstructure of the nanowire was also confirmed by a TEM diffraction pattern, as shown in Figure 4b. The ring shape diffraction pattern indicates a short-range crystalline order, and the foggy pattern
surrounded by the ring pattern is indicative of defects in the graphitic phase . This short-range crystalline nature of the pyrolyzed carbon was confirmed by Raman spectroscopy. Due to the limited spatial resolution of the Raman spectroscopy, the carbon post instead of the suspended carbon nanowire was tested as shown in Figure 4c. The G-band at 1,590 cm−1 is representative of sp 2 hybridized graphitic material and the D-band Tangeritin shown at 1,350 cm−1 stems from disordered carbon [24, 25]. The overlapping shape of the D-band and the G-band and the relative intensity of the two bands are consistent with TEM results indicating that the pyrolyzed carbon is a mixture of ordered and disordered carbons. Figure 4 TEM image (a) and corresponding diffraction patterns (b) of a carbon nanowire and Raman spectrum from a carbon post (c). The TEM image was obtained at the edge of an approximately 190-nm-size bare carbon nanowire. The oxygen-to-carbon (O/C) ratio is often used to characterize the composition of carbonized materials. In Figure 5a,b, we show high-resolution XPS spectra in the C1s and O1s regions, respectively, of a pyrolyzed bulk carbon structure and a SU-8 precursor structure. The C1s spectrum of the SU-8 structure consists of peaks at 283.7 and 285.9 eV. The peak at 285.9 eV corresponds to carbon bound to oxygen and the peak at 283.