Current Components
Use the Checkboxes on top of the Applet for control.

Electron Leakage (drift) Current

Turn off all Checkboxes except for leakage
and
electron.

If no dots flow, the clik the checkboxes on & off a few times.

Observe the blue dots that flow
down the potential hill. These blue dots are the leakage electrons.

Hole leakage (drift) Current

Repeat the above for leakage and hole,

Observe the red dots that flow
up
the
potential hill. These red dots are the leakage holes.

Electron Injection (diffusion) Current

For injection and electron,

Observe the blue dots that move
horizontally from ntype to ptype.
These are the injection electrons.

Hole Injection (diffusion) Current

For injection and Hole,

Observe the red dots that flow
in the valence band, horizontally. They move from ptype
to ntype.
Electron Recombination Current

Turn off all Checkboxes except for recombination
and
electron.

Observe the blue dots that flow
from the conduction band to the valence band, vertically.

Change doping level of Na, see what changes to the
initial height of the minority carrier density, diffusion length, and the
length which recombinaion can occure. Note that the diffusion length and
the length which recombination can occur decreases as the doping level
increase.
Hole Recombination Current

Turn off all Checkboxes except for recombination
and
hole.

Observe the red dots that flow
from the valence band to the conduction band, vertically.

Change doping level of Nd, see what changes to the
initial height of the minority carrier density, diffusion length, and the
length which recombinaion can occure. Note that the diffusion length and
the length which recombination can occur decreases as the doping level
increase.
At zero applied bias (click the reset button at bottom),
the magnitudes are such that

electron injection current = electron leakage current.

hole injection current = hole leakage current.

Since they flow in opposite direction, the total electron
current is zero and the total hole current is zero. Therefore the total
current (electron current + hole current)

Can you verify #4 in the applet ?
NOTES

In the energy band diagram, electron
energy
increases
as
you go up. But hole
energy
increases
as
you go
down. Therefore, both leakage currents
(electrons and holes) flow in the direction of decreasing energy.