  The photovoltaic properties of carbon nanotube/Si heterojunction solar cells
were investigated using network films of high quality single-walled carbon
nanotubes (SWNTs) grown by atmospheric-pressure floating-catalyst chemical
vapor deposition. Because of the optimization of the device window size and the
utilization of SWNT thin films with both low resistivity and high transparency,
a high photovoltaic conversion efficiency of greater than 12% was achieved for
SWNTs/Si heterojunction solar cells without any post processing, such as
carrier doping treatment. In addition, the high stability and reproducibility
of the photovoltaic performance of these devices in air was demonstrated.
