I-V curve from Quasi 3D model

[ijasmuhammed98]

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Question

quasi3d_t1_GaAs.txt

2d_iv_GaAs.txt

1. Why is the current values obtained from solve_quasi_3d, plotted in log scale to get the I-V curve? What does this curve imply ? Why are the current values too low?
2. Why is the I-V curve calculated using 2 diode model different from the I-V curve obtained from solve_quasi_3d ?

Could you please explain the meaning of I-V curve from solve_quasi_3d

I'm attaching both the I-V curves and their codes .

[dalonsoa]

Hi @ijasmuhammed98 ,

The data is plot in log scale in the first case because that is what you ask for: look at the last bit of that script:

plt.figure(2)
plt.semilogy(V, abs(I))
plt.show()

You plot the absolute value of the current in log scale for the Y axis. Plotting it that way or a different way is entirely optional. When creating that example, it was deemed more appropriate doing it so, but it is entirely up to you. It is about displaying the data.

The quasi-3D model produces the results in current units (A), while the 2-diode model uses current density units (A/m^2). The area used by the quasi-3D model is defined implicitly when setting the size of the pixels of the masks in your script:

# Size of the pixels (m)
Lx = 10e-6
Ly = 10e-6

Since the masks have 120x120 pixels, that results in a cell of 1.44 cm^2. If you divide the current density of the 2-diode model by 10,000 (the number of square centimetres in a square meter), you should get both curves in current units (A) and in a similar order of magnitude. The curves will not overlap since the quasi-3D model takes into account the shadowing of the metal grid, but they should be similar.

I hope this helps.