6.3.2 AFM Nanowire Generation

In [28] it is suggested that a nanowire, which is patterned using a combination of AFM nanodots, separated at 0.5nm intervals will have an increased half-width due to the increased time for the lateral diffusion of anions. This phenomenon was added to the simulator and a nanodot was generated in the LS simulator to mimic the one presented in [28], as is shown in Figure 6.11. As in [28], generating nanodots with 20V pulses for 1ms, while displacing the tip laterally by 0.5nm resulted in a nanowire with a height of approximately 1nm and a half-width of 13nm.

Figure 6.11: Nanowire topography simulated using a sequence of AFM nanodots (top) and the nanowire's cross-section (bottom).

Instead of generating nanowires as a series of nanodots, an approach using empirical equations which govern nanodot height and half-width under various conditions, from [53] was implemented in the simulator, as described in Chapter 5. This type of simulation is much quicker as it allows for a nanowire to be treated in a single simulation step as opposed to thousands of single nanodot generation steps. The nanowires also exhibit a shape based on the SCD distribution. Figure 6.12b shows simulated nanowires alongside the experimental sample from [53] in Figure 6.12a, at bias voltages ranging from 6V to 10V, with a 5ms pulse time and 72% humidity.

Figure 6.12: Simulations of AFM-generated nanowires.

(a) Effects on nanowire topography with varying bias voltages, ranging from 6V to 10, with a 5ms pulse time and 72% humidity: Experimental results from [53].

(b) Effects on nanowire topography with varying bias voltages, ranging from 6V to 10, with a 5ms pulse time and 72% humidity: Simulated results.

(c) Cross-section of the nanowires from Figure 6.12b.