Environmental Engineering Reference
In-Depth Information
Figure 8.1 Efficiency of intermediate band
solar cell [100] (top curve, labeled
This work
)
compared with two-junction tandem cell
(second curve) and single-junction cell (lower
curve) at one sun illumination. The abscissa is
the value of the smaller gap, with the values for
the second (larger; labeled E
H
in Figure 8.2) gap
in eV printed along the upper two curves, which
assume two separate gaps. These curves are
calculated assuming a black body spectrum at
6000 K [100].
concentration of donor impurities, such as P in Si. At a level of doping above theMott
transition concentration, the electronic states are linear combinations of electron
waves centered on the impurity sites, and are delocalized. The Fermi level then lies
within the distribution of impurity ground-state levels. In that case of large donor
concentration, the energy gap between the Fermi level and the conduction band edge
Figure 8.2 Sketch of hypothetical intermediate band semiconductor. Adapted from Ref. [101],
Figure 7.1a, p. 141.
