Figure 2 EQE (a) and integrated current Jisc (b) of the
SCH solar cells with ICO layer of different thickness.
The EQE and integration short-circuit current density
(Jisc) for the SCH solar cells with back ICO films of
varying thickness are depicted in Fig. 2 (a) and (b), respectively. The
EQE curves almost overlap in the short wavelength range due to the same
front structure. However, the quantum efficiency of long wavelength
increases first and then decreases with increasing of the back ICO
thickness. The back ICO thickness corresponding to the highest EQE is
about 110 nm and the corresponding Jisc is 39.68
mA/cm2. As a comparison, Jisc for the
SCH solar cell without back ICO is 38.51 mA/cm2. The
significant improvements in long wavelength response and
Jisc by adding the back ICO layer with a suitable
thickness of 110 nm indicate that the ICO/Ag combination functions well
as a back reflector.