Carbon nanotube arrays for photovoltaic applications

Vertically aligned periodic arrays of carbon nanotubes (CNTs) are used to create topographically enhanced light-trapping photovoltaic cells. The CNTs form the back contact of the device and serve as a scaffold to support the photoactive heterojunction. Molecular beam epitaxy is used to deposit CdTe and CdS as the p/n-type materials and ion-assisted deposition is used to deposita conformal coating of indium-tin oxide as the transparent top contact. X-ray diffraction data shows (111) texture of the CdTe. Photo-current produced per cm(2) of footprint for the CNT-based device is 63 times that of a commercially available planar single crystal silicon device.