The Plot Window

Reading results

This figure carries the whole solution graphically: the bands, the carrier densities and the field, on three axes that share a depth scale. The panel on the right selects what is drawn.

01The three vertical axes

The Band Diagram opens beside the results window after an ordinary solve. Everything shares a single horizontal axis, Depth (nm), measured from the surface. Three quantities are laid over it, each with its own vertical scale:

• Energy (eV), on the left — the band diagram, on the same convention as the results window, with the bulk Fermi level at zero.
• Carrier density (cm⁻³), on the inner right — the electron and hole profiles.
• Electric field (V/cm), on the outer right — with a faint line at zero, so the sign of the field is clear.

The two right-hand axes appear only while something is drawn on them. Hide every line belonging to one and its axis and scale disappear with them, which keeps a plot of the bands alone from carrying two empty axes.

02What is drawn

Which traces are present depends on the solve, but the names are fixed:

• On the energy axis, Conduction band and Valence band, the Intrinsic level, and the Fermi energy as a horizontal line. Under a bias that splits the two quasi-Fermi levels, the single Fermi line is replaced by Quasi Fn and Quasi Fp.
• On the density axis, Electron density and Hole density.
• On the field axis, the Electric field.
• If a Schrödinger region was solved and Show quantised levels is ticked, each bound level is drawn as a short horizontal mark spanning the region, at its absolute energy on the band diagram.

03The Lines panel

The right-hand panel, headed Lines, holds one checkbox per trace, and toggling a box shows or hides that trace immediately. Show all and Hide all act on every trace at once; Show quantised levels governs the bound-state marks as a group.

Hiding traces is the usual way to make a busy plot legible — the densities and the field can share the graph with the bands, but rarely need to be read at the same time. Remember that an axis withdraws once its last visible line is hidden, so the remaining traces are rescaled to fill the frame on their own.

Show legend turns the legend on and off, and the legend itself can be dragged to wherever it obscures least.

04Scale and view

Two scale toggles sit in the same panel, each shown only when the axis it governs is present:

• Log scale: carriers switches the density axis between linear and logarithmic. A logarithmic axis is the only way to see a depleted region and an accumulation peak in one view, since they differ by many orders of magnitude.
• Symlog scale: E-field does the same for the field, with a linear span across zero so that a field which changes sign is still readable.

Full scale returns the view to the full extent of the data after you have zoomed or panned. Zooming, panning and saving an image are handled by the toolbar above the plot, which is the standard Matplotlib navigation bar.

05Copying the data

Copy data places the plotted traces on the clipboard as tab-separated columns — a depth column first, then one column per trace, ready to paste into a spreadsheet or plotting tool. It copies the visible traces only, so hiding what you do not want is also how you choose the columns. For the results text and the layer structure, and for saving to a file, see Copying, Saving and Exporting.