Kris's Research Notes

January 31, 2011

Droplet Experiments — Effect of Droplet Bonds

Filed under: GaAs Simulations — Kris Reyes @ 6:00 pm

In previous experiments, we did not observe a critical thickness. I wanted to see how the bonding energy within a droplet (i.e G0-G0 bond strength) affected this. So I ran some trials with lower intra-droplet bonding energies, which means the droplets would wet the surface more readily. Here I fixed \epsilon = 0.20, T = 500K, r_{\downarrow Ga} = 0.1 monolayers/second, r_{\downarrow As} = 0.01 monolayers/second. I varied \gamma(G0, G0) \in \left\{0.26, 0.25\right\} eV. Recall all other Ga-Ga bonds are fixed at 0.25 eV.
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Droplet Experiments — Effect of Droplet Etching

Filed under: GaAs Simulations — Kris Reyes @ 5:32 pm

The previous droplet experiments did not allow for droplet etching, which we model as instability at the droplet/substrate interface. In these set of runs, we turn it back on. We focus the idea of a critical thickness — the amount of deposited Gallium where droplets start to occur.

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January 17, 2011

Droplet Experiments — Effect of Next-Nearest neighbor bonds

Filed under: GaAs Simulations — Kris Reyes @ 7:13 pm

We had briefly questioned whether adding next-nearest neighbor bonds would increase the droplet widths. The thought was that if these bonds existed within the droplet, we could control the geometry and perhaps force the droplets to be wider. Here are the results of one small run I did to test this. It turns out that increasing next-nearest bond strengths reduces the size of the droplets.
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Droplet Experiments — Exact Thickness

Filed under: GaAs Simulations — Kris Reyes @ 6:20 pm

In these set of runs, we require the amount of Gallium deposited is exact, in contrast to earlier runs where there was some variance in this amount. We also look at droplet statistics as a function of Gallium thickness.

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