Photovoltaic characteristics of nitrogen-doped amorphous carbon thin-films grown on quartz and flexible plastic substrates by microwave surface wave plasma CVD

Abstract

We report the photovoltaic characteristics of n-type conductivity of nitrogen-doped amorphous carbon (a-C:N) thin-films grown on quartz and heat tolerant (up to 260 °C) flexible polytetrafluoroethene plastic substrates by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) at low temperature (<100 °C). For film deposition at various gas composition pressures ranging from 50 to 90 Pa in the CVD chamber, we used argon as carrier gas, nitrogen as dopant and methane as carbon plasma source. The X-rays photoelectron spectroscopy (XPS) measurement shows that nitrogen content in the films grown on plastic substrates is higher compared with the films grown on quartz substrates. The optical measurements show that the optical band gap of the films grown on plastic substrate is lower compared with the films grown on quartz at the same parameters. The temperature dependence conductivity and photoresponse measurements show that the electrical conductivity of the films grown on plastic substrates is much higher compared with the films grown on quartz substrates. Our experimental results show that amorphous carbon deposited on flexible plastic substrates is reliable for photovoltaic applications.