Carrier Concentration

This applet will graph electron (black) and hole (red) concentrations for a given temperature and Fermi level. These parameters may be entered using the text field provided, or by dragging the appropriate slider. Note that the energy is measured in eV.

Four scaling modes are provided:

Logarithmic The (natural) log of the concentration will be plotted.

Automatic The scale will adjust to the height of the "taller" of the two distributions. This will cause the scale to change every time the Fermi level or temperature changes.

Whole range The scale will adjust only according to temperature. The scale will not change as the Fermi level is adjusted (but the concentration will not go off the scale), so the distributions may not always be visible.

Locked The scale will remain at whatever range is currently set. This can be useful for getting a feel for how the magnitude of the concentration changes with fermi level and with temperature.

The ratio between the effective masses of holes and electrons may be set using the "hole/electron mass ratio" field; valid ratios are those in the range [0.1,10].

The size of band gap may be changed using the field provided; in addition, the proportion of the display occupied by the band gap may be independently modified using the "display range / gap" field. This proportion must be between 1.1 and 20, so the band gap will occupy between (approximately) 5% and 90% of the available area.

Documentation

Logarithmic	The (natural) log of the concentration will be plotted.
Automatic	The scale will adjust to the height of the "taller" of the two distributions. This will cause the scale to change every time the Fermi level or temperature changes.
Whole range	The scale will adjust only according to temperature. The scale will not change as the Fermi level is adjusted (but the concentration will not go off the scale), so the distributions may not always be visible.
Locked	The scale will remain at whatever range is currently set. This can be useful for getting a feel for how the magnitude of the concentration changes with fermi level and with temperature.