AN3432

Photocurrent production basics of silicon solar cells

Doc ID 019041 Rev 1

3/24

1

Photocurrent production basics of silicon solar cells

1.1

The photovoltaic effect

To generate a current through a semi conductor, some energy is required to extract the

electron from the valence band to the conduction band. This energy is greater than material

Thus in case of silicon solar cell, if the photon energy (sunlight carrier) E = h

ν is higher than

Figure 1.

Current generation through a semiconductor

1.2

The solar cell model

independent of output cell voltage. However, when this voltage increases, a part of this

current is dissipated in p-n junction. This is why the equivalent model, shown in Figure 2,

consists in a current generator (photocurrent), a diode (intrinsic p-n junction), two

Conduction

band

é

Valence

band

E = h > E

ν

gap

E(eV)

E

V

E

c

E= E -E

gap

c

v

Forbidden

area