Silicon-based solar cells Characteristics and production processes ...

Silicon-based solar cells – characteristics and production processes
software were realized with the assumption of the impurity profile type erfc for N D =
3,6x10 20 atom/cm 3 and the junction depth of 0,5 μm.
Fig. 6. Energy band displacement and creation of photovoltage V as a result of cell
illumination, depending on the concentration of donor impurity N D = 3,6x10 20 atom/cm 3 and
the homogeneous concentration of acceptor impurity N A =1,5x10 16 atom/cm 3 .
As a result of the cell illumination, the position of the energy bans in the p-type
area becomes lower by the value qV, which is mainly dependent on the acceptor
impurity concentration. The value of the diffusion potential U D depends on the
impurity concentration according to the equation [16]:
2
( N n )
where: k - Boltzmann constant
T - temperature [ o K]
n i - concentration of intrinsic charge carriers
U = kT qln N
(1)
D
A
E
i
The above dependences are highly significant for the design and production
engineering of solar cells on the basis of crystalline silicon. If we lower the level of
impurity N A in the cell’s base material, this will heighten its resistivity and the
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