## 3 Results
### Transmission Electron Microscopy Analysis
The FEB tip in Figure 6a shows no grains in the upper edge area in the binary image. Here, a clear difference in the number of grains can be seen by a comparison of the binary images. The 260 pA tip shows a much more homogeneous distribution of grains in the edge region, while only a few grains are visible in the 9 pA tip. Of course, when the threshold is increased, more grains are visible. However, the binary images' relative representation is only intended to allow a direct comparison of the tips and their differences. Furthermore, there is a clear difference in the spacing and distribution of the grains throughout the entire nanostructure. The FEB tip in Figure 6a shows a very homogeneous distribution of the grains all over the nanostructure. For the FIB tips, the number of grains in Figure 6c is much larger; therefore, the spacings between the grain are much lower than in Figure 6b. In order to deepen previous investigations, the tips from the 9 pA and 260 pA ion current and the 340 pA FEB tip are again significantly enlarged. Figure 7a-c shows the HRTEM images of the tip ends. The left side in Figure 7a-c shows the attempt to capture the grains using the brightness differences. Characteristic for the HRTEM analysis are different gray values in the image depending on the intensity of the penetrating electron beam. That is, the thicker the grains, the darker they appear. In the comparison of the three top images of Figure 7, it is thus repeatedly visible in detail that the grain size of the tips differs significantly. The grains from the FEB tip in Figure 7a and the 260 pA FIB tip in Figure 7c are clearly smaller and more densely distributed than the 9 pA FIB tip in Figure 7b. Due to a more homogeneous distribution of the grains, it is possible to conclude that there is a much lower probability of defects in the edge area of the tip, as already discussed in Figure 6. Otherwise, it can be seen that the amorphous carbon areas in the FEB tip take up more space than in the FIB tips. This, in turn, leads to a decrease of Pt grains in the edge area. The right half of Figure 7a-c and the subsequently selected areas electron  
Figure 5: HRTEM analysis overview images of the PIC nano-tips (**a**) 340 pA EB (**b**) 9 pA IB, (**c**) 46 pA IB, (**d**) 90 pA IB and (**e**) 260 pA IB. (**f–j**) the magnified images of the tips for the FFTs (**k–o**). diffraction (SAED) and their FFTs deepen the investigation from Figure 5. Figure 7d first shows a SAED of the 340 pA FEB tip and clearly visible interplanar planes in the FFT (Figure 7e) corresponding to the 111, 200, 220, and 311 planes. The 9 pA FIB (Figure 7f) tip shows only the interplanar planes of the 111 and 200 planes. Additionally, the FFT from Figure 7g confirms this by the intensity of the diffraction rings and the absence of the outer rings corresponding to the 220 and 311 planes, respectively. Figure 7h shows the FFT and Figure 7i-k the SAEDs of the 260 pA tip with much smaller grains. The difference in the intensity of the diffraction rings and spots is obvious. Moreover, with similar intensity of the 111 and 200 levels, visibility of the 220 and 311 levels is given. Since the 311 planes with an interplanar spacing of 1.1826 A is already close to the resolution limit of the HRTEM of 0.8 A, this grating can only be detected by marking the diffraction spot and the inverse FFT. On both the 260 pA FIB and the 340 pA FEB tip with their common feature of small grains, the small interplanar planes are visible through the FFTs and the SAEDs. Thus, this leads to a correlation between the grain size and the intensity of the diffraction rings. Since the thickness of the tips is larger than the grains, amorphous regions of the DLC are overlaid by the lattice structures of the Pt, as well as several Pt grains by one another. Amorphous regions are always visible between the grains, as shown by the yellow marking in Figure 7d. However, it is difficult to study these regions and make detailed conclusions. All previous data on the grains refer to the accumulation of Pt crystallites.