  We present a near-infrared photoresponse study of single-walled carbon
nanotube/poly(3-hexylthiophene)-block-polystyrene polymer (SWCNT/P3HT-b-PS)
composite films for different loading ratios of SWCNT in the polymer matrix.
Compared to the pure SWCNT film, the photoresponse [(light current - dark
current)/dark current] is much larger in the SWCNT/polymer composite films. The
photoresponse is up to 157% when SWCNTs are embedded in P3HT-b-PS while for a
pure SWCNT film it is only 40%. We also show that the photocurrent strongly
depends on the position of the laser spot with maximum photocurrent occurring
at the metal-film interface. We explain the photoresponse due to exciton
dissociations and charge carrier separation caused by a Schottky barrier at the
metallic electrode - SWCNT interface
