Sustained Photovoltaic Effect from Nitrogen Rich Carbon Nitride (CNx) Prepared by Reactive Magnetron Sputtering

Nitrogen rich carbon nitride (CNx) materials were prepared using reactive magnetron sputtering from a pure nitrogen plasma at elevated deposition pressures and low deposition powers. Solid-state photovoltaic devices utilizing such materials were prepared and characterized. As-prepared CNx materials showed photoconductive behaviour and no photovoltaic effect. This was attributed to the p-doping effect of oxygen present in as-prepared CNx films resulting in formation of a compensated semiconductor. However, upon thermal annealing, CNx materials showed a pronounced photovoltaic effect consistent with the n-type semiconductor behaviour. This result demonstrates that nitrogen rich carbon nitride is a promising photovoltaic material for all-carbon photovoltaic solar cells.