CN103230807A - Method for preparing wide-spectral-response titanium dioxide thin film through ion beam doping - Google Patents

Abstract

The invention provides a preparation method of a wide-spectral-response titanium dioxide thin film. According to the invention, with a MEVVA source, V/N double elements are injected into a nano-grade titanium dioxide thin film, such that a metal/nonmetal-doped nano-grade titanium dioxide thin film is obtained. With the double-element-doped titanium dioxide thin film provided by the invention, light response range of titanium dioxide is expanded, light utilization range of titanium dioxide can be improved, photocatalytic efficiency of the film can be improved, and the film can be widely applied in the field of pptoelectronics.

Description

A kind of ion beam doping prepares the method for wide spectral response titanium deoxid film

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Technical field

The present invention relates to a kind of preparation method of wide spectral response titanium deoxid film, belong to the photoelectron material technical field.

Background technology

Titanium dioxide can be widely used in sewage disposal and air cleaning as the novel photocatalysis agent of green non-pollution, does not cause the wasting of resources and produces secondary pollution, can also be recycling.This strong oxidation can also be used for sterilizing, sanitation and health-care field.Also can make green clean energy resource solar cell and hydrogen production by water decomposition, for energy issue of world proposes a solution that has feasibility.But, TiO up to the present ₂The efficient of the light reaction particularly utilization rate to sunshine is still very low, so commercial Application can't realize at present on a large scale, still needs a large amount of research accumulation.How improving the photocatalysis performance of titanium dioxide, have crucial effects to solving the current energy and polluting two big world property difficult problems, is whole scientific circles problem demanding prompt solutions.

Titanium dioxide energy gap wideer (3.2 eV) has determined to excite the light of titanium dioxide can only be at about 390 nm of ultraviolet portion, and this part light only accounts for about 5% of solar energy, so titanium dioxide is very low to the utilization rate of sunshine.With regard to this problem in the past few decades in people done a large amount of research and want TiO ₂Utilization to light expands to the visible region.That common method has is metal-doped, nonmetal doping and metal/non-metal mixing and doping, and discovering really can be TiO by these means ₂Absorption to light expands to the visible light part.But because the controlled reliable structure of shortcoming mixes at present to TiO ₂Modification well below ideal value.In addition, people have also proposed composite semiconductor, and are compound by the semiconductor that two kinds of energy gaps are different, improve TiO ₂Utilization rate to light.Proposed many knots stacked solar cell concept solar cell research field people, realized that wide spectrum is with TiO ₂Absorption to light is extended to the visible light part.But, because composite semiconductor or tie the stacked solar cell complex manufacturing technology more and cost too high, limited its extensive utilization.

The optical property of material directly depends on its electronic band structure, in order to make titanium dioxide the response of light is expanded to the visible region, and the most direct method is exactly the electronic band structure that changes titanium dioxide itself.And the method that changes the titanium dioxide band structure is mixed to titanium dioxide exactly.From the eighties in last century, metal cation mixes and has obtained research widely as the means that change the optically catalytic TiO 2 performance.Humans such as Anpo have prepared the photochemical catalyst of Mn, Fe, Ni plasma doping, and have studied their optical absorption property and photocatalysis performance, and the result shows that red shift has taken place the titanium dioxide ABSORPTION EDGE.Metal-doped titanium dioxide can form a defective energy state and be called impurity energy level between semiconductor valence band and conduction band, for light induced electron provides a springboard, can utilize the lower excited by visible light electronics of energy, electronics (transits to impurity energy level earlier in two steps by valence band, transit to conduction band then) be transferred to conduction band, thereby reduce light induced electron-hole-recombination probability, make titanium dioxide expand to the visible light part to the response of sunshine, improved the utilization rate of sunshine.The titanium dioxide of calendar year 2001 Ashi has carried out the N doping, makes its response to sunshine expand to 500 nm, the anion doped focus that becomes people's research.The researcher is injected into TiO with the N element ₂In the nanotube, find that the N element doping increases photoelectric current.N mixes and to make film expand to conduction band mechanism to the response of light to be: the 2p energy level phase hydridization of the 2p energy level of N and O, thus cause energy gap to narrow down.Anion dopedly show better heat endurance with respect to metal cation, and also be significantly improved for the photocatalysis performance of visible light wave range.But can't provide a generally acknowledged theory for anion doped change optically catalytic TiO 2.

Except single element above-mentioned mixes, proposed recent years to adopt the way of two or more ion mixing and dopings to improve TiO ₂Photocatalysis efficiency.Zhao adopts sol-gel method to TiO first ₂Carried out Ni and B mixing and doping, found that the sample of mixing and doping is than the TiO that does not have doping or single Ni doped or B ₂Sample demonstrates better photocatalytic activity at visible region.People such as Cong adopt N and Fe mixing and doping TiO ₂, find that the mixing and doping sample demonstrates high photocatalysis effect.People such as Gai had proposed new codope method in 2009, design Mo/C codope method, utilize first principle that the new doping method that proposes is carried out theory analysis, the researcher finds that by analyzing the special Shi Shouzhu of codope is right, and defective can be with and be passivated, in the codope system of this passivation each other, height when carrier lifetime can be than independent doping, and Mo/C codope only improve valence band location, and can not change the position of titanium dioxide conduction band, be conducive to the carrying out of redox reaction.Find thus, to the local effect of carrier, participate in the water decomposition reaction thereby allow electric charge to shift when the atom pair of this passivation has each other been eliminated independent the doping.Mixing and doping is recently to TiO ₂An impressive progress of mixing and studying lacks controllability and stability owing to mix, and is difficult to provide a good theoretical explanation, and the research of this respect still is in the experimental data accumulation stage.Also do not adopt the ion injection to carry out the report of the research of hybrid ionic doping up till now.In this patent, we have proposed to utilize ion injection method, with the TiO of V/N ₂Carry out the metal/non-metal dual element and mix, obtain the TiO of wide spectral response ₂Film.

Summary of the invention

Technical problem to be solved by this invention is at TiO in the prior art ₂The shortcoming low to the utilization rate of sunshine provides a kind of preparation method of wide spectral response titanium deoxid film.

The titanium deoxid film of the metal/non-metal codope of the inventive method preparation adopts the MEVVA ion injection method.Ion injects the influence that has the solid solubility of not being subjected to as a kind of traditional doping means, is particularly suitable for mixing near sample surfaces; The element that injects can be chosen arbitrarily; Accurately controlled doping concentration and the degree of depth, rectilinear propagation are strong, uniform doping is good, certain flexibility is arranged and be easy to control in operation.In the codope system, height when carrier lifetime can be than independent doping, and can realize being with the purpose regulated and control to titanium dioxide, and MEVVA source ion injection method can realize large-area preparation, is used for industrial production.

Technical scheme of the present invention is that the V/N dual element successively is injected into TiO ₂Film, included concrete steps are as follows:

1) utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 400～500 oC insulation annealings, obtain anatase phase TiO ₂Film;

2) intense beam stream pulse V and the N ion that utilizes evaporation of metal multi sphere ion gun to draw successively is injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is from 3 * 10 ¹⁵To 5 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ², obtain the anatase phase TiO of V/N codope ₂Film.

The ion dose that injects in preparation process is different with energy, and control V/N ion is at TiO ₂Distribution in the film can be with the purpose regulated and control thereby reach to titanium dioxide.

TiO ₂The film preparation after-baking is that the insulation annealing time is 1～2 hour at 400～500 oC insulation annealings under oxygen atmosphere, obtains anatase phase TiO ₂Film.

The implanter that is used for injection metal/non-metal ion can be selected for use for industrial evaporation of metal multi sphere ion (MEVVA) source implanter.The characteristics of this kind implanter are that the bundle spot is big and evenly, line strong (reaching the mA level) can carry out high dose ion at short notice and inject, thereby greatly reduce the injection cost.

There is cooperative effect in the metal/non-metal codope in the titanium deoxid film system of the metal/non-metal codope that the present invention is prepared, this cooperative effect can be adjusted the band structure of material, improve photocatalysis performance, this cooperative effect mainly comes from: (1) metal ion mixing is conducive to nonmetallic ion-doped, codope can change the titanium dioxide energy gap, improves the absorption to visible light; (2) the metal/non-metal codope can effectively stop the compound of electron-hole pair, is conducive to the life-span of electron hole pair, thereby improves the photocatalysis performance of titanium dioxide.

The method that the present invention adopts ion implanted junction to close magnetron sputtering prepares the titania-doped film of V/N metal/non-metal dual element, has the unique advantage of the following aspects: the first, preparation cost is low, preparation technology is simple, controlled.The second, can prepare large-area film, be beneficial to practical application.Utilize the MEVVA source can realize the large tracts of land injection, and magnetron sputtering is very ripe film build method, is used for suitability for industrialized production.Three, because substrate is transparent quartz glass, also have broad application prospects in fields such as self-cleaning glass, antibiotic and sterilizing, self-cleaning anti-fog coats.Four, structure of the present invention is based on and can be with on the basis regulated and control titanium deoxid film, is to solve how to improve TiO ₂The key scientific problems of low photoelectric transformation efficiency.But though have theory to report for work to utilize ion injection method experimentally do not appear in the newspapers to.This structure can effectively can be with to titanium dioxide, improves the life-span of electron hole pair, thereby improves TiO ₂Photocatalysis efficiency.

Description of drawings

Fig. 1 can be with the schematic diagram regulated and control for the present invention prepares the V/N codope to titanium deoxid film.

Fig. 2 is the V/N codope titanium dioxide thin film ultraviolet-visible transmitted spectrum of present embodiment 5 preparations.

Fig. 3 is the V/N codope titanium dioxide thin film Raman spectrum of present embodiment 5 preparations.

Fig. 4 is the XPS spectrum of Ti, N in the V/N codope titanium dioxide thin film of present embodiment 5 preparation, V.

Fig. 5 is to the degraded of methylene blue solution under the irradiation of V/N codope titanium dioxide thin film ultraviolet-visible of present embodiment 5 preparation.

The specific embodiment

A kind of preparation method of wide spectral response titanium deoxid film comprises the steps:

1) utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 400～500 oC insulation annealings, obtain anatase phase TiO ₂Film.

2) intense beam stream pulse V and the N ion that utilizes evaporation of metal multi sphere ion gun to draw successively is injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is from 3 * 10 ¹⁵To 5 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ²Obtain the TiO of the anatase phase of V/N codope ₂Film.

Embodiment 1

Utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 500 oC insulation annealings, annealing time is 2 hours, obtains anatase phase TiO ₂Film, its thickness are 200 nm.Intense beam stream pulse V and N ion that MEVVA draws in the source successively are injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is respectively 3 * 10 ¹⁵Ions/cm ², line is 1 mA/cm ², obtain the TiO of V/N codope ₂Film.

Embodiment 2

Utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 500 oC insulation annealings, annealing time is 2 hours, obtains anatase phase TiO ₂Film, its thickness are 200 nm.Intense beam stream pulse V and N ion that MEVVA draws in the source successively are injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is respectively 5 * 10 ¹⁵Ions/cm ², line is 1 mA/cm ², obtain the TiO of V/N codope ₂Film.

Embodiment 3

Utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 400 oC insulation annealings, annealing time is 1 hour, obtains anatase phase TiO ₂Film, its thickness are 200 nm.Intense beam stream pulse V and N ion that MEVVA draws in the source successively are injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is respectively 3 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ², obtain the TiO of V/N codope ₂Film.

Embodiment 4

Utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 400 oC insulation annealings, annealing time is 2 hours, obtains anatase phase TiO ₂Film, its thickness are 200 nm.Intense beam stream pulse V and N ion that MEVVA draws in the source successively are injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is 3 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ², obtain the TiO of V/N codope ₂Film.

Embodiment 5

Utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 500 oC insulation annealings, annealing time is 2 hours, obtains anatase phase TiO ₂Film, its thickness are 200 nm.Intense beam stream pulse V and N ion that MEVVA draws in the source successively are injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is respectively 3 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ², obtain the TiO of V/N codope ₂Film.

Sample to the present embodiment preparation is analyzed, and sees Fig. 2 ~ 5.

Fig. 1 can be with the schematic diagram regulated and control to titanium deoxid film for preparation V/N codope.

The V and the N that inject have entered TiO ₂Lattice V ion partly substituted the Ti ion, N has partly substituted the position of O and has played acting in conjunction.Can the doping ion enter TiO ₂Lattice depend primarily on the radius of ion because V ⁴⁺Ionic radius is 7.2 nm and Ti ⁴⁺Ionic radius 7.4 nm are very approaching, so V ⁴⁺Be easy to enter TiO ₂Lattice, replace Ti ⁴⁺The position, formed the TiO that V mixes ₂Film.In the N ion implantation process, because V ⁴⁺The existence of ion may influence N and enter TiO ₂Lattice V ⁴⁺The ion existence can increase N and enter TiO ₂The lattice probability, form the TiO of V/N codope easily ₂Sample.V ⁴⁺3d ion and the acting in conjunction of Ti3d ion make conduction band reduce, and N2p electronics and the acting in conjunction of O2p electronics make valence band raise (as shown in Figure 1), reduce TiO so the common synergy of mixing of metal V and non-metal N ion can change the material band structure ₂Energy gap, increased TiO ₂Thereby the absorption to visible light improves its photocatalysis effect.In addition, the V/N codope can reduce the recombination probability of electron-hole pair, improves TiO ₂The photocatalysis effect.

Fig. 2 is the V/N codope titanium dioxide thin film ultraviolet-visible transmitted spectrum of preparation.

As can be seen from the figure TiO ₂Sample has a very strong absworption peak near 380 nm, and the V/N ion injects the back sample altogether in visible region absorption enhancing, and along with the visible region absorption intensity that is increased in of implantation dosage also increases.The more important thing is that the V/N ion injects TiO altogether ₂Absworption peak moves to the visible light direction behind the film, and this explanation is after V/N injects altogether, makes TiO ₂Energy gap narrow down absorption spectrum generation red shift.

Fig. 3 is the V/N codope titanium dioxide thin film Raman spectrum of preparation.

As can be seen from the figure all samples are 146,199,399,516 and 640 cm ^-1Raman peaks has all appearred in the position, and this explanation ion injects and do not change TiO ₂Crystalline phase.The V/N ion injects the pure TiO of Raman peaks strength ratio of sample ₂A little less than, and along with the increase Raman peaks of implantation dosage becomes not only weak but also wide, this is because ion injects the existence of the lattice defect that produces causes.

Fig. 4 is the XPS spectrum of Ti, N, V in the V/N codope titanium dioxide thin film of preparation

Fig. 4 (a) is the XPS spectrum of Ti 2p, and as can be seen from the figure the binding energy of Ti 2p is 458.7 eV and 464.5 eV, respectively corresponding Ti2p _3/2And Ti2p _1/2The peak, this is and Ti ⁴⁺Ions binding can be consistent.In order to obtain injecting back N and V valence state, the N in the sample and V have been carried out XPS analysis, as Fig. 4 (b) with (c).Can see two peaks from the XPS spectrum of N, one at 401 eV and another one near 395.8 eV.401 eV peaks belong to

Attitude mainly belongs to the N of ADSORPTION STATE.Another one is to belong at 395.8 eV peaks

Attitude, this binding energy shows the existence of Ti-N key, this peak shows and has formed O-Ti-N and Ti-O-N key that these results show that V/N injects TiO altogether ₂In the sample, N not only successfully is injected into TiO ₂In and exist with the chemical bond attitude, that is to say that N has substituted the position of O.The XPS spectrum of V2p such as Fig. 4 (c) have shown two peaks among the figure, one at 517.6 eV, and another one is at 519.7 eV.Are V at 517.6 eV ⁴⁺Binding energy, show that V has substituted the position of Ti.Peak, another one 519.7 eV position is the binding energy of metallic state V.This result shows that the V ion injects a back part and entered TiO ₂Lattice substituted the position of Ti, another part still exists with atomic state.

The V/N codope titanium dioxide thin film of Fig. 5 present embodiment 5 preparation under the irradiation of ultraviolet-visible to the degraded of methylene blue solution.The methylene blue solution of getting 40 ml concentration and be 5 mg/L is placed in the glass culture dish of lid, has one of film to face up in sample.Mercury lamp is as light source (OSRAM, its typical wavelengths is 365 nm), and power is 250 W.With sample before ultraviolet light irradiation, be placed in the dark environment 30 minutes, reach adsorption equilibrium.The methylene blue solution of degrading under the irradiation of mercury lamp was then measured the concentration of methylene blue in the solution every 30 minutes.The concentration of methylene blue solution is measured by UV-vis absorption spectrum (Shimadzu UV 2550), and its absworption peak position is about 664 nm.Total degradation time 4 hours.As can be seen from the figure V/N dual element doped samples is than pure TiO ₂Catalytic efficiency improves a lot.

Embodiment 6

Utilizing direct current reaction magnetron sputtering is the TiO of 200 nm at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 500 oC insulation annealings, annealing time is 2 hours, obtains anatase phase TiO ₂Film, its thickness are 200 nm.Intense beam stream pulse V and N ion that MEVVA draws in the source successively are injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is respectively 5 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ², obtain the TiO of V/N codope ₂Film.

Claims (2)

1. the preparation method of a wide spectral response titanium deoxid film is characterized in that, comprises the steps:

1) utilizing direct current reaction magnetron sputtering is 200 nm TiO at quartz glass substrate surface deposit thickness ₂Film, and under oxygen atmosphere 400～500 oC insulation annealings, obtain anatase phase TiO ₂Film;

2) intense beam stream pulse V and the N ion that utilizes evaporation of metal multi sphere ion gun to draw successively is injected into TiO ₂Film, the accelerating potential of V, N ion is respectively 30 kV and 20 kV, and implantation dosage is from 3 * 10 ¹⁵To 5 * 10 ¹⁶Ions/cm ², line is 1 mA/cm ², obtain the anatase phase TiO of V/N codope ₂Film.

2. preparation method according to claim 1 is characterized in that, the insulation annealing time in the step (1) is 1～2 hour.

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