For the [alpha]-type semiconductor, with [alpha] = n, p, [S.sub.[alpha]] is the surface recombination rate, [D.sub.[alpha]] the diffusion constant, [L.sub.[alpha]] the diffusion length, and [Z.sub.[alpha]] the thickness.
The surface recombination rate at the top and the bottom contacts is set to zero.
The surface recombination rate at the top and bottom contacts is set to zero.
Hence, the surface recombination rate [U.sub.s] can be defined at the inner edge of the surface space charge region and is related to the effective surface recombination velocity [S.sub.eff] through
The SRH surface recombination rate is expressed by an expression similar to the SRH bulk recombination rate with replacing the bulk electron and hole concentrations n and p by the surface potential dependent surface carrier concentrations [n.sub.s] and [p.sub.s].
In CNTs/Ti[O.sub.2] composite the photocatalytic enhancement is generally attributed to electron capture by the CNTs and in the surface recombination rate
According to the Shockley-Read-Hall theory, the surface recombination rate is proportional to the density of the surface states.
The spectral responses of internal quantum efficiency in the short wavelength range also shows the improvement due to reduced surface recombination rates on the front surface of the cell.