Figure 5 Schematic of the nanochannel scratching with V stage and V tip in the opposite direction when V stage   >  V tip . Schematic of the machining state after ( a ) one and ( b ) two AFM scanning cycle. ( c ) Schematic of the cross section of TSA HDAC mouse the machined nanochannel. To demonstrate the capability of the AFM-based fabrication method presented

in this study, five channels with different machining parameters corresponding to the conditions mentioned above were created on the GNS-1480 nmr aluminum alloy sample. The scan size (L tip), scan rate of the AFM (f), and the number of line-scanning within one scanning process (s) are set to 10 μm, 4 Hz, PKC412 and 300, respectively, for all scratching tests. Thus, the feed velocity of the AFM tip V tip is calculated to be 133.3 nm/s using Equation 1. The machining results are described and analyzed in detail in Section ‘Results and discussion’. Results and discussion Figure 6 shows the AFM and SEM images of the nanochannels scratched with the stage motion and the feed rate in the same direction. As shown in Figure 6a, the nanochannel machined with the stage velocity V stage of 50 nm/s and the normal load of 36.06 μN has two-ladder structure, which agrees well with the condition shown in Figure 2c discussed in the part (1) of Section 3.1 (V stage < 0.5V tip). However, the fluctuation

of the channel bottom is very large. Due to V tip larger than V stage, the displacement of the tip relative to the sample in one scanning process is in the positive direction of x axis shown in Figure 2a. As shown Avelestat (AZD9668) in Figure 7a which is the SEM image of the AFM diamond tip, the edge and the face of the tip can be observed clearly. Figure 7b shows the front view of the nanochannel fabrication process, and Figure 7c shows the A-A cross section indicated in Figure 7b, which represents the condition with the displacement of the tip

relative to the sample in one scanning process in the positive direction of x axis. Δ′ and x′ axis, shown in Figure 7c, are defined as the projections of the feed of the tip (Δ) and x axis in the A-A cross section. In addition, α is the attack angle between the tip and the sample surface which can be used to determine the removal mechanisms of the materials. Thus, considering the geometry of the AFM tip shown in Figure 7c, the edge of the AFM tip plays a main role in the scratching test. For increasing α, three removal mechanisms have been proposed: plowing, wedge formation, and cutting [21]. For AFM diamond-tip-based nanomachining, if the attack angle is larger than a certain value (75° in [22]), cutting is the dominant mechanism. Using Equation 11, the real pitch in scratching is calculated to be 10 nm.