Through SEM imaging, we anticipate that these highdensity CdS nanotube arrays will provide novel ways
of manipulating light absorption, carrier generation,
and collection. As observed from the SEM images, the
nanotubes with a 35-nm inner diameter and a 35-nm
intertube space will enable carriers to be effectively
collected before they are lost by recombination, and
hence will significantly improve carrier collection for
absorbers with short (less than 100 nm) minority carrier
diffusion lengths. Copper phthalocyanine (CuPc) is
an example of such an absorber.