Study On Properties Of C And N Doped Ti-O Films Prepared By Monopole Pulsed Sputtering:Using Gas Carbon And Nitrogen Sources

With the rapid development of modern society,the effects of environmental pollution and corrosion on society economy and industry production became more and more serious.The development of clean renewable energy,the control of environmental pollution and exploitation of corrosive resistant technology has become an urgent requirement for the sustainable development of human society.Titanium dioxide(TiO2)is widely used in many fields such as solar cells,surface antibacterial,wastewater treatment and degradation of organic dyes because of its good chemical stability,non-toxic and pollution-free,and excellent photocatalytic activity.However,due to the large band-gap width of TiO2,the transition energy of valence electrons from valence band to conduction band is high,which results in low photocatalytic activity under sunlight.Modification of TiO2,narrowing the band-gap width of TiO2,reducing the excitation energy of wakening photocatalytic activity have become a hot topic in the current research by which improving the photocatalytic performance of TiO2.Non-metallic element doping is one kind of modification methods.In this paper,a monopole pulsed DC magnetron sputtering was used to prepare C-doped and co-doped Ti-0 of C and N(C:Ti-O and C++N:Ti-O)thin films using CO2 and N2 as reactant gases.The influences of process parameters on the composition,structure,mechanical properties,surface morphology,band gap width,surface energy and photocatalytic activity of the film were studied,and the photocatalytic and antibacterial properties of the film were also evaluated.In order to obtain good adhesion between film and substrate,interface technology was explored firstly.By changing negative voltage of substrate and deposition time,series of Ti transition layer were prepared,and then Ti-O film was deposited on the Ti layer.Based on the mechanical characterization,the optimum interfacial layer technology was obtained.Proper substrate negative and deposition time are beneficial to adhesion,especially deposition time.Furthermore,the Ti transition layer can effectively improve the hardness of the films and significantly improve the young's modulus of the films.By adjusting the flow rates of CO2 and N2 reactant gases,series of C:Ti-O and C+N:Ti-O films were prepared.The atomic force microscope(AFM)study of C:Ti-O thin films shows that the increase of CO2 flow rate leads to the change of the surface morphology of Ti-O thin films from island-like structure to columnar structure and the increase of surface area,which are conducive to the improvement of photocatalytic activity.The structure of the films was analyzed by X-ray diffraction(XRD),Glanced incidence X-ray diffraction(GIXRD)and Raman spectroscopy.The results show that the C:Ti-O films are dominated by the rutile phase and there is a certain amount of amorphous TiO2.XPS analysis confirmed the existence of Ti-C bond inside the C:Ti-O film,indicating that the C atom replaces part of the O atom and the C element successfully achieves doping.The results of band-gap width calculated by tauc's plotting method in terms of the transmission spectrum show that the doped C element can effectively reduce the band-gap width of the film;in the case of narrower band-gap,the results of photocatalytic degradation of methyl orange(MO)and the antibacterial experiment show that the higher the crystallinity,the higher the photocatalytic activity and the better the antibacterial effect.Antibacterial properties are closely related with photocatalytic activity,and the optimal reaction gas parameters were confirmed.The characterization results of surface morphology of C+N:Ti-O thin films elucidate the decreases of deposition rate and the increasingly tendency of island-like with the increase of N2 flow rate.XR/D analysis show that C+ N:Ti-O films are mainly a large number of amorphous TiO2 and Ti2O3 phases.After annealing,the diffraction peak of amorphous TiO2 decreases dramatically and rutile phase formed.Ti2O3 phase were also disappeared and the crystallinity of the film increased.XPS analysis confirmed the existence of Ti-C and Ti-N-O bond in the film,indicating that the C and N atoms have entered the film and replaced some of the oxygen atoms.The doping of C and N was achieved successfully.The doping of jointed C and N element can reduce the band-gap width of the film more effectively than that of C element.The band-gap width is reduced from undoped Ti-O film 3.21 eV and carbon-doped Ti-O film 3.08 eV to 2.72 eV;Photocatalytic experiments and antibacterial experiments show that the photocatalytic activity and antibacterial performance of the prepared C++N:Ti-O thin film are relatively low,but after annealing treatment,the amorphous TiO2 gradually transforms into the rutile phase,the crystallinity of the film is improved,the.photocatalytic activity is enhanced,and the antibacterial rate is up to 81%.