## 3 Results and Discussion
### AFM LON on TaS\({}_{2}\) Surfaces
#### 3.1.2 Static-Tip LON  
As already demonstrated in a previous study [15] a modification of the regular _dynamic-tip_ LON was used to perform accurate and reproducible patterns. In this case, instead of oxidizing in tapping mode, a static oxidation method was developed in which the oscillation amplitude was stopped during the application of the voltage pulse (_static-tip_ LON). This new methodology affords a higher degree of control of the morphology and profiles of the patterned structures by fine-tuning the oxidation conditions (Figure 3a). Although we do not have yet a theoretical study that confirms our hypothesis, we can suggest based on the experimental observations, that the oscillation induces a less controllable oxide dot, probably due to the change in size of the water capillary during the oxidation process in the _dynamic-tip mode_ oxidation that enlarge the oxidation area because the tip-to-sample distance is changing during the oscillation. However, in the _static-tip mode_ the tip-to-sample distance remains constant, reaching a better control on the pattern shape. (See a schematic carton describing both processes in the Supplementary Materials, Figure S2). Further experiments were directed toward optimizing the precision of the _static-tip_ oxidation by adjusting the pulse duration and the applied voltage, while maintaining a constant humidity and tip-sample distance. It appears that the height and the final area of the oxidized pattern directly depend on the voltage and time pulse, respectively. Once again, threshold potentials were found to be very sensitive to experimental instant conditions, varying in the approximately same range as for _dynamic-tip_ oxidation. Once the threshold voltage was established, the resulting oxide sizes could be precisely controlled by adjusting the pulse duration (Figure 3b). In order to assure a precise oxidation of sub-nanometric features on the surface, pulse times within the tens of millisecond time-scale were required. Once the proper working parameters are set, _static-tip_ LON enabled a uniform and reproducible patterning of oxide motifs on large surface areas of thick 2H-TaS\({}_{2}\) flakes. Figure 4a shows the high reproducibility reached with the _static-tip_ mode. To illustrate the uniformity reached, the 1040 oxide nanodots, could be fitted to a Gaussian distribution with a standard deviation as small as 0.15 nm. Figure 2: (**a**) AFM topography image of three oxide patterns performed at \(V_{\mathrm{ox}}=-26\) V, \(t_{\mathrm{ox}}=40\) ms and different tip-sample distances, from top to down: 16 nm, 15 nm and 14 nm, respectively, and the corresponding height profiles of the oxide patterns; (**b**) Set of three topography images of 3 \(\upmu\)m \(\times\) 3 \(\upmu\)m showing dots oxidized at \(-21\) V with an increasing pulse time of (1) 100 ms, (2) 200 ms, and (3) 300 ms, respectively, with their corresponding height profiles on the right side. This result is comparable with the precision reached with _dynamic-tip_ LON performed on silicon [28]. The improved control over the patterning technique achieved via _static-tip_ LON opened the door to the oxidation of ultrathin few layer TaS\({}_{2}\) samples (<5 nm) [15]. Nevertheless, regardless of the high level of precision that can be achieved in static mode, long pulse durations and high values of voltage pulses, gave rise to oxide motifs that exhibit the characteristic rippled structure already observed in _dynamic-tip_ LON. Figure 4: _Static-tip_ LON performed on TaS\({}_{2}\) thick flakes. (**a**) AFM topography image patterned with a university logo made out of 1040 oxide dots, oxidized at \(-34\) V and 150 ms. Average dot heights are 0.58 \(\pm\) 0.15 nm; (**b**) Topography image of an oxide pattern performed at a constant voltage value of \(-34\) V and 150 ms. The oxide dots were grown at \(v\) = 100 nm/s scan speed; (**c**) Topography image extracted from a selected region of Figure 4a.