Figure 9.

External quantum efficiency (EQE) spectra obtained in the top-down (dotted curve) and in-plane (filled curve) geometries of the device. The maximum value achieved in the case of the top-down configuration is 37% (at 850 nm), while in the planar one it is 10% (at 850 nm). The two line shapes are very different: in the top-down setup the EQE curve is very similar to that of a commercial p–n silicon solar cell, with a low absorption at ultraviolet wavelengths, whereas in the in-plane case, there is a rise that is characteristic of MWCNT absorption.