Formation of C3N4 thin films through the stoichiometric transfer of the bulk synthesized gC(3)N(4) using RFM sputtering

Abstract

A new approach to form stoichiometric C3N4 thin films through radio frequency magnetron (RFM) based sputtering method, compacted gC(3)N(4) powder is used as the sputtering target. Thin-film samples are deposited on different substrates under Ar and N-2 as plasma media for different durations. These samples are analyzed by scanning electron microscope, transmission electron microscope, atomic force microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis. The photoelectrochemical (PEC) studies including chopped light voltammetry, incident photo-to-current conversion efficiency, and electrochemical impedance spectroscopy along with photoluminescence (PL) studies are also performed on C3N4/TiO2 heterojunction samples formed through the RFM sputtering technique. The use of Ar as the plasma medium allows the formation of a thin film of stoichiometric C3N4 in the C3N4TiO2 heterojunction sample. The PEC and PL studies concluded that the C3N4/TiO2 heterojunction formed under Ar plasma offered a higher current density and lower impedance as compared to that offered by the C3N4/TiO2 heterojunction formed under N-2 plasma. It signifies the beneficial use of compressed C3N4 as the sputtering target to form a stoichiometric and photoactive C3N4 thin films without the difficulty in controlling the N-2 gas flow rate with graphite as the target in the sputtering process.