Feasibility of In-Line Continuous Hot-Wire Chemical Vapor Deposition for Proto- and Nanocrystalline P-I-N Solar Cells

Hot Wire Chemical Vapour Deposition (HWCVD) is a very suitable technique for homogeneous deposition of thin films on continuously moving substrates in an in-line manufacturing system. As there are no high frequency electromagnetic fields, scaling up is not hampered by finite wavelength effects or rigorous requirements to avoid inhomogeneous electrical fields. Deposition has been undertaken with the substrates facing upward, thus further simplifying the mounting of the substrates, which can either be rigid or flexible. Amorphous (protocrystalline) as well as nanocrystalline silicon thin films with device-quality properties have been achieved on moving substrates. We present p-i-n solar cells deposited on a linearly moving substrate already showing efficiencies of 7.8%, despite two air breaks. The potential for high deposition rate and fast roll-to-roll deposition is also discussed.