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Hello!

I am working on a project that involves modeling a 3D Nanowire with two sections (a p-doping and n-doping section) of GaAs material with a Silicon substrate underneath. I have some user defined generation to simulate light hitting the nanowire with a sample generation rate. I am trying to get an I-V curve for the nanowire for voltages applied on the ends of the nanowire, however, for voltages of higher magnitude (mainly large negative voltages greater than -6 volts) it will not yield a result with a sofficient convergence. It will just timeout as the convergence values under the Progress tab are mostly all above 1. I've been messing around with the settings and tried increasing the Relative Tolerance so that it accepts more solutions, however, at some point the results get really unreliable. One possibility is that the current going through is getting too large to model, but leading up to the region beyond -6 Volts, the current does not seem to diverge at all.

I was able to successfully model a similar nanowire using a 2D model and I found that the current seemed to diverge at around -10 Volts. However, we really need a 3D model for the nanowires as the nanowires are more cylindrical and the substrate underneath the the nanowire is large.