# Kris's Research Notes

## August 27, 2012

### VLS Nanowire Simulations – C Bonds

Filed under: KMC, Nanowire — Kris Reyes @ 5:30 pm

In this note, we continue to study the effect of energy parameters on VLS nanowire growth. Here we examine the role of the $\gamma(B,C)$ and $\gamma(C,C)$ bonds, the liquid-solid and solid-solid bond strengths, respectively.

We repeat the procedure followed in this post, fixing $\gamma(B, B) = 0.4$ eV and varying $\gamma(B, C)$ and $\gamma(C, C)$ between 0.35 and 0.55 eV. Here are the results:

As expected, nanowire growth occurs only for $\gamma(B,C) < \gamma (C,C)$. Otherwise, mixing occurs.

We also ran trials over larger $\gamma(C,C) = 0.5, 0.6, 0.7$ eV, fixing $\gamma(B,C) = 0.35$ eV and temperature $T = 623$ K (higher than the temperature used in the above simulations). Here are the results of each choice of $\gamma(C,C)$ over 16 trials.

### $\gamma(C,C) = 0.7$ eV

We see that as $\gamma(C,C)$ increases, the tapered base becomes larger. In the extreme case $\gamma(C,C) = 0.7$ eV, the base spans the entire width of the domain, which apparently discourages the growth of the nanowire.