Amorphous carbon thin film deposition by microwave surface-wave plasma CVD for photovoltaic solar cell

Amorphous carbon (a-C) thin films were successfully deposited on various substrates, such as, silicon, quartz, glass and flexible plastic at low temperature (<100/spl deg/C) by microwave (MW) surface-wave plasma (SWP) chemical vapor deposition (CVD), a newly developed deposition method for solar cell application. The camphor dissolved with alcohol mixture and methane were used as carbon precursors, while argon was used as carrier gas. Nitrogen and iodine were used as dopants. The deposited a-C films were characterized by UV/VIS/NIR spectrophotometer, SEM, Raman scattering and XPS measurements. In this paper, we report experimental results of the optical, physical and structural properties of the films; the results suggested that it is possible to control film growth rate and optical band gap, and consequently improve photoconductivity by proper selection of deposition parameters, optimizing dopants and appropriate annealing temperature. Our research work is in a progressive stage to realize cheap, reasonably highly efficient and environmentally friendly a-C-based photovoltaic solar cell in the future.