Abstract
The synthesis of nanostructured hydrogenated amorphous carbon (aโC:H) films doped with nitrogen using microwaveโassisted surface wave plasma chemical vapour deposition on quartz and pโsilicon substrates is reported. By controlling the deposition parameters, the Tauc band gap has been varied from 2.4 to 1.75 eV. Field emission scanning electron microscopy observations indicate that the films are nanoโ structured and the particle size varies considerably depending on the deposition conditions. Nitrogen seems to be responsible for the formation of the nanostructure. Xโray photoelectron spectroscopy studies with depth profiling indicate that nitrogen is not uniformly distributed in the bulk of the films and the films are observed to be rich in carbon near the pโsilicon substrate. Nitrogen concentration increases away from the substrate towards the top surface. Resistivity, visible Raman and nitrogen/carbon ratio studies indicate that a significant amount of sp^3^ carbon is present in the films and nitrogen seems to be a weak donor in the aโC:H matrix. Weak photovoltaic action is observed in nitrogenโdoped aโC:H/pโsilicon cells. (ยฉ 2006 WILEYโVCH Verlag GmbH & Co. KGaA, Weinheim)