CN1436606A

CN1436606A - Prepn process of vanadium oxide film material

Info

Publication number: CN1436606A
Application number: CN 03115643
Authority: CN
Inventors: 陆卫; 潘梅; 陈效双; 李志锋; 李宁; 季亚林; 钟红梅
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2003-03-04
Filing date: 2003-03-04
Publication date: 2003-08-20
Anticipated expiration: 2023-03-04
Also published as: CN1225318C

Abstract

The present invention is one sol-gel process of preparing vanadium oxide film material and features that vanadium acetylacetonate oxide is used to replace alkoxide of pentavalent vanadium salt to make the prepared sol stable, capable of being stored for long time and capable of being used for several times. In addition, the sol has less toxicity and thus less harm to the operator. Using the sol can prepare vanadium oxide film with homogeneous property and high optimized orientation.

Description

The preparation method of vanadium oxide thin film material

Technical field

The present invention relates to the metal-oxide film material, be specifically related to the preparation method of vanadium oxide thin film material.

Background technology

Vanadium oxide (VO ₂) be near a kind of transition metal oxide that the metal-semiconductor phase transformation takes place 68 ℃.Follow this phase transformation, VO ₂Electricity, optics and magnetic property hop all takes place, wherein resistivity has 10 ⁵The variation of magnitude, the infrared transmittivity at 2.5 μ m places before the phase transformation 70% become be close to opaque.Therefore, VO ₂Film all has important use at aspects such as optics and storage, optoelectronic switch, solar energy control and laser radiation protections.Particularly since the nineties, VO ₂The development that thin-film material is used for micro-metering bolometer no-refrigeration infrared focal plane device has obtained breakthrough, thereby the development of thin-film material also more and more is subject to people's attention.

Present VO ₂The preparation method of thin-film material has evaporation, sputtering method and sol-gel process etc.Wherein, it is simple that sol-gel process has preparation technology, low to equipment and operating process requirement, is easy to advantages such as doping.The VO of existing sol-gel process preparation ₂Film all is to utilize the ethanoxygen salt (VO (Opr) that contains the pentavalent vanadium ₃) as presoma, the ethanoxygen salt of pentavalent vanadium has good water-disintegrable, and it is dissolved in the mixed solution of water and organic solvent, adds small amount of acid and an amount of stabilizer, hydrolysis through a period of time just can obtain having certain viscosity, is suitable for the even colloidal sol of even glue.Organic precursor film by even glue obtains obtains vanadic oxide (V through heat treatment ₂O ₅) film, obtain vanadium oxide film at the reducing atmosphere hydrogen annealing at last.See Coordination Chemistry Reviews:Jacques Livage, Optical and electrical propertiesof vanadium oxides synthesized from alkoxides, 1999,190-192:391-403. and ThinSolid Films:Songwei Lu, Lisong Hou, Fuxi Gan, Surface analysis and phasetransition of gel-derived VO ₂Thin films, 1999,353:40-44.But because this presoma pentavalent vanadium alcohol oxygen compound is water-disintegrable strong excessively, very easily excessively hydrolysis forms gel, can't long term storage and repeatedly use.Moreover, because will be reduced to tetravalence to the vanadium of pentavalent in this technology, must use reducing atmosphere hydrogen, hydrogen can cause blast as if mixing then with air in certain amount, and this has just increased the danger of operation.Therefore, must guarantee the special construction requirements such as sealing of annealing device.In addition, the pentavalent compound of vanadium toxicity in its each valence state is the strongest, and is very big to the human body infringement.

Summary of the invention

For solving the problem that exists among the existing vanadium oxide thin film material preparation technology, the objective of the invention is to propose a kind of to the environment body harmless, precursor sol is stable, the preparation method of the vanadium oxide thin film material that operating procedure is easy.

Have now found that acetylacetone,2,4-pentanedione vanadyl (VO (acac) ₂) water-disintegrable moderate, the precursor compound good stability with its preparation not only can reduce the toxicity of reactant, and film do not need reducing atmosphere in annealing process, and the requirement of operating process and experimental facilities is all reduced.

Its preparation process is:

1. the preparation of precursor solution

A. at room temperature, will analyze pure or the pure acetylacetone,2,4-pentanedione vanadyl of top grade is dissolved in the excessive methanol, if the vanadium oxide film that preparation is mixed, then dissolve in the salt of the required element of respective amount simultaneously.The molar concentration that makes solvent evaporate into vanadium in right amount is 0.125mol/l.

B. with the trickle insoluble particles that is not more than in the 0.2 μ m injection filter elimination solution, film is polluted to prevent it.Solution after will filtering with magnetic stirring apparatus slowly stirred 24 hours, made its abundant hydrolysis, and sealing was placed ageing more than three days then, promptly obtained being suitable for transparent, the uniform precursor sol of even glue.At this moment, formed the polymer that contains the V-O long-chain in the colloidal sol, so can be used to prepare the precursor thin-film of vanadium oxide.Keeping under the airtight state, this colloidal sol can be placed for a long time and not become gel or produce precipitation.

2. the preparation of thin-film material

The precursor sol for preparing is dripped on the substrate, use the sol evenning machine whirl coating.Rotating speed 3000-3500 rev/min, time 20-25 second.Behind the even glue, precursor film was toasted 20-30 minute in 70 ℃ of-80 ℃ of baking ovens, to remove unnecessary solvent.Repeat even glue and bake process, till reaching required film thickness.Then film is placed in the blanket of nitrogen stove with substrate, under 550 ℃-650 ℃ temperature heat treatment 15-30 minute, promptly obtains the vanadium oxide film of homogeneous.

Utilize the vanadium oxide film of the inventive method preparation to have following advantage:

1. the vanadium oxide film that can prepare the character homogeneous easily, have (110) preferred orientation.

2. do not need complicated instrument and equipment, save the energy, and be easy to realize ion doping, for the pilot study advantageous particularly.

3. Zhi Bei collosol stability is good, can long-term storage, repeatedly use.In addition, this presoma toxicity is less relatively, helps operating personnel's health.

Description of drawings

Fig. 1. the XRD test result of the vanadium oxide film of the present invention's preparation.

Embodiment

Below we are further described the present invention by embodiment:

1. clean used vessel:

The flask that will use, beaker, measuring cup, injection filter etc. clean once with fresh chromic acid lotion, with the running water flushing, use deionized water rinsing again 3 times then.Cleaned vessel are standby after 5 hours in baking under 80 ℃ the condition.

2. the preparation of precursor solution

(1) at room temperature, 2.65g is dissolved in the 100ml methyl alcohol with the pure acetylacetone,2,4-pentanedione vanadyl of top grade, at preparation doping mol ratio tungsten: during the doping vanadium oxide film of vanadium=5: 100, the tungsten trichloride (WCl that to dissolve in 1 milliliter of molar concentration simultaneously be 0.5mol/l ₆) solution, and constantly stir, make methyl alcohol evaporate into 80ml, this moment, the molar concentration of vanadium was 0.125mol/l.

(2) with the trickle insoluble particles in granularity≤0.2 μ m injection filter elimination solution, film is polluted to prevent it.Solution after at room temperature will filtering with magnetic stirring apparatus slowly stirred 24 hours, made its abundant hydrolysis, and sealing was placed ageing more than three days then, promptly obtained being suitable for transparent, the uniform precursor sol of even glue.

3. the preparation of thin-film material

(l) substrate is handled: use Si-SiO ₂Make substrate, the substrate cleaning step is:

(a) substrate is immersed in the acetone, use ultrasonic 5 minutes of ultrasonic cleaner,, use ultrasonic 5 minutes of ultrasonic cleaner, use deionized water rinsing with again substrate being immersed in the ethanol behind the deionized water rinsing;

(b) substrate being immersed proportioning is hydrogen peroxide: ammoniacal liquor: in the alkaline rinse of deionized water=1: 1: 5, and boiled 5 minutes, use deionized water rinsing, repeat (b) step once again;

(c) substrate being immersed proportioning is hydrogen peroxide: hydrochloric acid: in the acid wash liquid of deionized water=1: 1: 6, and boiled 5 minutes, use deionized water rinsing;

(d) substrate after will cleaning dries up to side direction with rubber pipette bulb, places 80 ℃ of baking ovens standby.The cleaning process of substrate is very important, because its clean-up performance directly has influence on the adhesiveness of precursor solution and the uniformity of film.

(2) spin coating of film: the precursor sol for preparing is dripped 2-3 drip on the substrate, with rotation sol evenning machine whirl coating.3000 rev/mins of rotating speeds, 20 seconds time.Behind the even glue, precursor film was placed in 80 ℃ of baking ovens baking 20 minutes with substrate, to remove unnecessary solvent.Repeat even glue and bake process 10 times, can obtain the film that thickness is about 3000 nanometers at last.Then film is placed in the blanket of nitrogen stove with substrate, heat treatment half an hour under 600 ℃ the temperature, promptly obtains the vanadium oxide film of homogeneous.The purpose of heat-treating under blanket of nitrogen is in order to avoid airborne excessive oxygen makes that film oxidation is vanadic oxide (V ₂O ₅).

4. the test of thin-film material: through the D/max-γ A type X-ray diffractometer test that Japan company of science produces, the film that the inventive method makes is for having the monocline phase oxidation vanadium (m-VO of height (110) orientation ₂), see Fig. 1.Heat treatment temperature is high more, and orientation is good more, based on to considerations such as the needs of thin film physics character and energy consumptions, generally under 600 ℃ film is heat-treated.

Claims

1. the preparation method of a vanadium oxide thin film material comprises the preparation of precursor solution, and even glue whirl coating is characterized in that this preparation method is as follows:

(1) preparation of precursor solution:

A. at room temperature, to analyze pure or the pure acetylacetone,2,4-pentanedione vanadyl of top grade is dissolved in the excessive methanol, if the vanadium oxide film that preparation is mixed then dissolve in the salt of the required element of respective amount simultaneously, and the molar concentration that makes methyl alcohol evaporate into vanadium in right amount is 0.125mol/l;

B. use≤trickle insoluble particles in the 0.2 μ m injection filter elimination solution, to prevent that it from polluting film, solution after will filtering with magnetic stirring apparatus slowly stirred 24 hours, make its abundant hydrolysis, sealing was placed ageing more than three days then, promptly obtained being suitable for transparent, the uniform precursor sol of even glue;

(2) preparation of thin-film material:

The precursor sol for preparing is dripped on the substrate, use the sol evenning machine whirl coating, rotating speed 3000-3500 rev/min, time 20-25 second; Behind the even glue, precursor film was placed in 70 ℃ of-80 ℃ of baking ovens baking 20-30 minute with substrate, to remove unnecessary solvent; And repeat even glue and bake process repeatedly, till reaching required film thickness; Then film is placed in the blanket of nitrogen stove with substrate, under 550 ℃-650 ℃ temperature heat treatment 15-30 minute, promptly obtains the vanadium oxide film of homogeneous.

2. according to the preparation method of claim 1 vanadium oxide thin film material, it is characterized in that said substrate is Si-SiO ₂Material.