Figure 1. Schematic of ZnO/CdS/CIGS solar cell structure (a),(b)
ZnO/CdS/CIGS-Si solar cell CIGS structure
Where ψ the electrostatic potential, the free electron n and free hole
p, trapped electron nt and trapped hole
pt as well as ionized donor-like doping
ND+ and ionized acceptor-like doping
NA- concentrations are all given in
terms of the different band gap energy levels by the Boltzmann and
Fermi-Dirac distributions, and are a function of the position “x”.
Jn and Jp are the electron and hole
current densities respectively. The term Gop is the
optical carrier generation rate due to illumination and R is the total
recombination rate accounting for direct (band to band) and indirect
(Shockley-Read-Hall) recombination traffics.