CN107402241A - Gas sensor based on tungsten oxide/titanium oxide core-shell nano line and preparation method thereof - Google Patents
Gas sensor based on tungsten oxide/titanium oxide core-shell nano line and preparation method thereof Download PDFInfo
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- CN107402241A CN107402241A CN201610338328.3A CN201610338328A CN107402241A CN 107402241 A CN107402241 A CN 107402241A CN 201610338328 A CN201610338328 A CN 201610338328A CN 107402241 A CN107402241 A CN 107402241A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
- G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles
Abstract
The present invention discloses gas sensor based on tungsten oxide/titanium oxide core-shell nano line and preparation method thereof, uses the array being made up of tungsten oxide/titanium oxide core-shell nano line to set platinum electrode in substrate for core, and tungsten titanium composite bed is set between platinum electrode and array.In the inventive solutions, to the ultra-thin titanium oxide shell of gas absorption and reaction with catalytic activity and certainly to construct the orderly core-shell structure gas sensitive of new one-dimensional to tungsten oxide nano is compound, to realize that air-sensitive performance improves, because superthin structure titanium oxide has notable catalytic activity to gas absorption, simultaneously, the hetero-junctions that two oxides Heterogeneous Composite is formed has nanometer cooperative effect and Heterojunction Effect in structure, and, orderly one-dimensional nano structure array can provide efficient diffusion admittance for gas molecule, vertical orientation oldered array Structure Gas Sensor can ultrafast sensitive detection nitrogen oxides at room temperature.Preparation condition is easily controllable simultaneously, and technique is simple.
Description
Technical field
The invention belongs to functional material preparation field, more particularly, is related to based on tungsten oxide/titanium oxide core-shell nano
Gas sensor of line and preparation method thereof.
Background technology
Into 21 century, industrialized level fast development, but natural environment for the survival of mankind are with ecology by tight
Destroy again, there is a large amount of toxic and harmful gas (such as NO in air2、NO、H2S、CO、SO2Etc.).NOx class toxic gases, energy
Acid rain corrosion building and skin are enough formed, can also produce chemical fumes, suction triggers cough, causes respiratory tract disease what is more
Disease.Therefore make efficiently and accurate detection is very urgent with the sensor of prevention toxic and harmful gas.Obtain high performance receive
Rice sensor, will prepare the nano material that can provide these high-performance possibilities first.
MOS type gas sensor has the advantages of inexpensive, high sensitivity, easily controllable and operation,
Thus by more and more extensive concern, but at present the more ripe gas sensitive metal-oxide semiconductor (MOS) of research have ZnO,
SnO2、TiO2Deng, but they cannot be used for efficient detection NOx class gases.With research deeply, the report such as Akiyama M in 1991
Road WO3Ceramics are the high sensitive material for detecting NOx in the environment of 300 degree.Since then, numerous researchers are triggered to WO3's
Research.WO3It is a kind of metal-oxide semiconductor (MOS), is a kind of surface conductance (resistance) control type gas sensitive.WO3Plane of crystal
Atomic property enliven, easy adsorption gas molecule, and when gas molecule is adsorbed in plane of crystal can make its internal carrier
Corresponding change occurs for concentration, shows as the resistance variations of sensor.In view of tungsten oxide enliven atom be located at plane of crystal because
This greatly expands the contact area of plane of crystal and gas, can effectively improve air-sensitive performance.1-dimention nano cable architecture
Tungsten oxide has attracted the research of numerous researchers because of its huge specific surface area.It can lead to by research in recent years
Hydro-thermal method, vapor phase method, sol-gel etc. is crossed to be made.The results show, the tungsten oxide of 1-dimention nano cable architecture improve really
The sensitivity of detection gas, but this can not still reach the marketization and the requirement of integra-tion application.In order to obtain high selectivity, height
Sensitivity, low operating temperature, the gas sensor of high stability, mainly improve gas sensing property by gas sensitive modification at present
Energy.
The content of the invention
It is an object of the invention to overcome the deficiencies of the prior art and provide a kind of one-dimensional tungsten oxide/titanium oxide nucleocapsid in order
Nano wire and its array, and the gas sensor element using this array composition and preparation method and application.In the present invention
Technical scheme in, with to gas absorption and reaction with catalytic activity ultra-thin titanium oxide shell with certainly to tungsten oxide nanometer
Line is compound to construct the orderly core-shell structure gas sensitive of new one-dimensional, to realize that air-sensitive performance improves, due to superthin structure oxygen
Changing titanium has notable catalytic activity to gas absorption, meanwhile, the hetero-junctions that two oxides Heterogeneous Composite is formed has in structure
There are nanometer cooperative effect and Heterojunction Effect, moreover, one-dimensional nano structure array can provide efficient expansion for gas molecule in order
Passage is dissipated, vertical orientation oldered array Structure Gas Sensor can ultrafast sensitive detection nitrogen oxides at room temperature.Meanwhile this is multiple
Mould assembly gas sensor preparation condition is easily controllable, and technique is simple, has important real value and Research Significance.
The technical purpose of the present invention is achieved by following technical proposals：
One-dimensional tungsten oxide/titanium oxide core-shell nano line in order, using tungsten oxide as core, using titanium oxide as shell, in tungsten oxide
Vanadium oxide is equably wrapped up in periphery, and tungsten oxide/titanium oxide core-shell nano line length is 800-1000nm, tungsten oxide it is a diameter of
20-30nm, the thickness of titanium oxide is 10-20nm, and tungsten oxide and titanium oxide form coaxial nucleocapsid heterojunction structure.
In the above-mentioned technical solutions, tungsten oxide/titanium oxide core-shell nano line length is 850-1000nm, tungsten oxide it is straight
Footpath is 25-30nm, and the thickness of titanium oxide is 10-18nm.
Nano-wire array is formed in substrate by one-dimensional tungsten oxide/titanium oxide core-shell nano line in order, i.e. tungsten oxide/oxidation
Titanium core-shell nano line is configured basically perpendicular to substrate surface, to form nano-wire array, macroscopically shows as membrane structure, oxygen
It is substantially consistent with film thickness to change tungsten/titanium oxide core-shell nano line length, is 800-1000nm, preferably 850-1000nm.
Based on the gas sensor of tungsten oxide/titanium oxide core-shell nano line, by substrate, platinum electrode, tungsten titanium composite bed and oxidation
Tungsten/titanium oxide core-shell nano linear array composition, platinum electrode is set in substrate, tungsten titanium composite bed is set on platinum electrode, in tungsten
Tungsten oxide/titanium oxide core-shell nano linear array is set on titanium composite bed, and tungsten oxide/titanium oxide core-shell nano linear array is had by one-dimensional
Sequence tungsten oxide/titanium oxide core-shell nano line composition, tungsten oxide/titanium oxide core-shell nano line are basically perpendicular to tungsten titanium composite bed, with
Form nano-wire array, macroscopically show as membrane structure, tungsten oxide/titanium oxide core-shell nano line length substantially with film thickness one
Cause, be 800-1000nm, preferably 850-1000nm.
In the above-mentioned technical solutions, tungsten oxide/titanium oxide core-shell nano line, using tungsten oxide as core, using titanium oxide as shell,
Vanadium oxide is equably wrapped up in the periphery of tungsten oxide, and tungsten oxide/titanium oxide core-shell nano line length is 800-1000nm, tungsten oxide
A diameter of 20-30nm, preferably 25-30nm；The thickness of titanium oxide is 10-20nm, preferably 10-18nm；Tungsten oxide and titanium oxide
Form coaxial nucleocapsid heterojunction structure.
In the above-mentioned technical solutions, platinum electrode is interdigitated platinum electrode.
In the above-mentioned technical solutions, tungsten titanium composite bed thickness is 100-200nm, preferably 120-150nm.
The preparation method of above-mentioned gas sensor, carry out as steps described below：
Step 1, using magnetron sputtering in substrate deposited metal platinum, as electrode, using Pt metal as target, with inertia
Gas is sputter gas, keeps vacuum to be less than 4 × 10 in sputter procedure-4Pa, sputters 1-2Pa of operating air pressure, and sputtering power is
90-100W, 20-25sccm of inert gas flow, sputtering time are 1-3min；
In step 1, choice of the substrates single-sided polishing silicon chip, or alumina ceramic plate.
In step 1, substrate is covered using electrode template, so that metal platinum forms interdigital row platinum electrode in substrate.
In step 1, the use of the purity of metal platinum is 99.999%.
In step 1, the use of inert gas is nitrogen, helium or argon gas, purity 99.999%.
In step 1, the thickness of deposited metal platinum is 80-120nm.
Step 2, using the type ultrahigh vacuum of DPS- III to golden in the deposition handled by step 1 to targets magnetic sputtering film plating machine
Belong to deposits tungsten film material plies in the substrate of platinum, using tungsten as target, using inert gas as sputter gas, in sputter procedure
Vacuum is kept to be less than 4 × 10-4Pa, sputtering operating air pressure are 1-2Pa, sputtering power 90-100W, and inert gas flow is
40-45sccm, sputtering time are 20-25min；
In step 2, the use of the purity of tungsten is 99.999%.
In step 2, the use of inert gas is nitrogen, helium or argon gas, purity 99.999%.
Step 3, the W film prepared using vacuum high-temperature tubular type furnace apparatus to step 2 carries out crystalline growth tungsten oxide nanometer
Line, first oxygen in equipment is drained with inert gas, then is passed through the mixed gas of oxygen and inert gas as ambiance,
In tungsten oxide nano growth course, it is respectively 0.2sccm and 40-45sccm to control oxygen and inert gas flow, is controlled
Growth pressure is 180-200Pa in stove, and tube furnace is raised to 620-660 DEG C from 20-25 degrees Celsius of room temperature, 1-3 DEG C of heating rate/
Min, 2-4 hours are incubated at 620-660 DEG C, then naturally cool to room temperature and take out sample；
In step 3, it is respectively 0.2sccm and 40sccm to control oxygen and inert gas flow, grows pressure in control stove
Power is 180Pa；Tube furnace is raised to 630-650 DEG C for 20-25 degrees Celsius from room temperature, 1-3 DEG C of heating rate/min, 630-650
DEG C insulation 3-4 hours, then naturally cool to room temperature.
In step 3, inert gas is nitrogen, helium or argon gas, purity 99.999%.
In step 3, oxygen purity 99.999%.
Step 4, the annealing of tungsten oxide nano, tungsten oxide nano prepared by step 3 is at 350-450 DEG C and empty
It is annealing insulation 1-2 hours under gas atmosphere, naturally cold afterwards to promote the fully oxidized of tungsten oxide nano and stablize crystal orientation
But to room temperature；
In step 4, in order to the product of growth (tungsten oxide nano) to be transformed into stable W18O49, to ensure film
The stabilization of air-sensitive performance to product film, it is necessary to be made annealing treatment, and from room temperature, 20-25 degrees Celsius are heated up, programming rate
For 1-3 DEG C/min.
Step 5, using vacuum high-temperature tubular type furnace apparatus prepared by step 4 and sunk on the tungsten oxide nano layer of the substrate of processing
Product Titanium, using Titanium as target, using inert gas as sputter gas, in sputter procedure holding vacuum less than 4 ×
10-4Pa, inert gas flow 40-45sccm, sputtering operating air pressure are 1-1.5Pa, sputtering power 90-100W, during sputtering
Between be 3-6min, preferably 4-5min；
In steps of 5, inert gas is nitrogen, helium or argon gas, purity 99.999%.
In steps of 5, the use of the purity of Titanium is 99.999%.
Step 6, the thermal anneal process of titanium, the deposited metal titanium film substrate after step 5 is handled is in 400-450 DEG C and air
Annealed 1-2 hours under atmosphere, to promote to aoxidize and synthesize titanium oxide shell, naturally cool to room temperature afterwards；
In step 6, selection uses Muffle furnace, anneals 1-1.5 hours.
In step 6, from room temperature 20-25 degrees Celsius heated up, programming rate is 1-3 DEG C/min.
Shown using Hitachi's ESEM Hitachi-S4800FESEM and JEOL JEM-2100F Flied emission transmitted electron
Knowable to the nano-wire array that micro mirror is prepared to the present invention is analyzed, one-dimensional tungsten oxide/titanium oxide core-shell nano line in order, with oxygen
Change tungsten is core, and using titanium oxide as shell, vanadium oxide, tungsten oxide/titanium oxide core-shell nano line are equably wrapped up in the periphery of tungsten oxide
Length is 800-1000nm, and a diameter of 20-30nm of tungsten oxide, the thickness of titanium oxide is 10-20nm, tungsten oxide and titanium oxide
Form coaxial nucleocapsid heterojunction structure.Nanometer linear array is formed in substrate by one-dimensional tungsten oxide/titanium oxide core-shell nano line in order
Row, i.e., tungsten oxide/titanium oxide core-shell nano line is configured basically perpendicular to substrate surface, to form nano-wire array, macroscopic view
On show as membrane structure, tungsten oxide/titanium oxide core-shell nano line length is substantially consistent with film thickness, as shown in accompanying drawing 1-3.Such as
Shown in accompanying drawing 4, tungsten oxide (W in tungsten oxide/titanium oxide core-shell nano line18O49) grown along (010) crystal orientation, it is monocrystalline, and occur
The characteristic peak of titanium dioxide, illustrate while tungsten oxide and titanium oxide be present.
As shown in Figure 5, use in the inventive solutions and the scheme of platinum electrode is set in substrate surface first, this
Sample one carrys out nano-wire array and directly contacted with gas, is easy to directly effective and easily tests, in view of successively being sputtered in preparation
Tungsten and Titanium, form the composite bed of tungsten and Titanium between platinum electrode and nano-wire array, and are used as conductance
Both layer connections, to facilitate overall use.
Nano wire one-dimentional structure significantly improves to be occurred between the specific surface area of composite construction sensitive material, different semi-conducting materials
Electric charge transfer forms hetero-junctions, oriented and ordered one-dimensional nano line array provides substantial amounts of gas absorption position and effective gas
Diffusion admittance, the advantage in terms of these three enable the gas sensor to realize the fast and effective detection to nitrogen oxides at room temperature,
Very big research space will be had in terms of senor operating temperature, the sensitivity for improving sensor and response speed is reduced.This
Invention provide a kind of vertical orientation, can at room temperature ultrafast sensitive detection nitrogen oxides it is one-dimensional in order tungsten oxide/titanium oxide
Core-shell nano cable architecture gas sensor, Preparation equipment is simple, technological parameter is easily controllable, cost is cheap.One-dimensional tungsten oxide core is received
Quasi- alignment features are presented because of its special metal W film thermal oxide growth technique in situ in rice noodles, and this quasi- directional array is shape
Into the indispensable precondition of the regulatable one-dimensional heterogeneous clad structure array of follow-up high-sequential directionality.By regulating and controlling to plate metal
The time of titanium, the uniform titanium oxide clad of different coating thicknesses can be not only formed, can also utilize and coat layer film
The directionality of sputtering stress regulation and control nano wire in sputter deposition process.Under appropriate coating thickness, height can be obtained
In order, the tungsten oxide of near vertical/titanium oxide core-shell nano line.With pure phase tungsten oxide one-dimensional certainly to nano wire base gas sensor
Compare, the vertical orientation gas sensor can reach high sensitivity at room temperature, and can realize to NO2The ultrafast detection of gas, ring
Restorability is answered to greatly improve.In addition, the gas sensor has special n-p transoid phenomenons, oxidisability NO at room temperature2Gas
The resistance of gas sensor reduces after Molecular Adsorption.
Brief description of the drawings
Fig. 1 is the electron scanning micrograph of the tungsten oxide nanometer linear array prepared using technical solution of the present invention.
Fig. 2 is the one-dimensional tungsten oxide/titanium oxide core-shell nano linear array column scan in order prepared using technical solution of the present invention
Electron micrograph, titanizing time are 3min.
Fig. 3 is the one-dimensional tungsten oxide/titanium oxide core-shell nano linear array column scan in order prepared using technical solution of the present invention
Electron micrograph, titanizing time are 6min.
Fig. 4 is the tungsten oxide nano and one-dimensional tungsten oxide/titanium oxide nucleocapsid in order prepared using technical solution of the present invention
The XRD of nano wire characterizes spectrogram, and wherein a is tungsten oxide nano, and b is one-dimensional tungsten oxide/titanium oxide core-shell nano line in order.
Fig. 5 is the processing step that one-dimensional tungsten oxide/titanium oxide core-shell nano line in order is prepared using technical solution of the present invention
Illustrate schematic diagram, wherein a, b, c, d, e represent five steps respectively, and 1 is electrode template, and 2 be platinum electrode, and 3 be substrate, and 4 be plating
Tungsten layer, 5 be tungsten oxide nanometer linear array, and 6 be tungsten oxide/titanium oxide core-shell nano linear array, and 7 be tungsten titanium composite bed.
Fig. 6 is the gas sensor prepared using technical solution of the present invention to 5ppmNO2The response of gas and operating temperature
Graph of relation.
Fig. 7 is the one-dimensional tungsten oxide/titanium oxide core-shell nano linear array in order prepared using technical solution of the present invention in room
To 0.5-5ppmNO under warm (i.e. 20-25 degrees Celsius)2The dynamic continuous response curve of gas is bent with response recovery time under 3ppm
Line, titanizing 3min during preparation.
Fig. 8 is the one-dimensional tungsten oxide/titanium oxide core-shell nano linear array in order prepared using technical solution of the present invention in room
To 0.5-5ppmNO under warm (i.e. 20-25 degrees Celsius)2The dynamic continuous response curve of gas is bent with response recovery time under 3ppm
Line, titanizing 6min during preparation.
Fig. 9 is gas sensor (i.e. tungsten oxide/titanium oxide that the preparation of different titanizing times is used using technical solution of the present invention
Core-shell nano line) response sensitivity and the graph of relation of gas concentration under respective optimum working temperature.
Figure 10 is one-dimensional tungsten oxide/titanium oxide core-shell nano line (the i.e. titanizing in order prepared using technical solution of the present invention
3min gas sensor) with simple tungsten oxide nano under respective optimum temperature to the selective comparison diagram of gas with various.
Figure 11 is the apparatus structure connection diagram that air-sensitive test is carried out in the present invention, wherein 1 is air admission hole, by micro
Injectant enters the tested gas of test volume；2 be gas sensor, is connected by probe with platinum electrode, is connected with external detection equipment
Connect；3 be that can heat and keep to the platform for needing temperature；4 is take the test sealing container made, and are 30L capacity；5 be mini
Fan, gas diffusion is helped, gas is dispersed in cube container；6 be gas outlet；7 be the electronics of controllable adjustment temperature
Controller unit；8 be excellent Leadd B.V UT70D resistance detection equipment, the resistance value of real-time display probe junction, and export extremely
Computer equipment；9 be that the resistance variations measured are recorded as into table and the computer terminal shown.
Embodiment
The present invention is raw materials used to use commercially available chemically pure reagent, the present invention is made with reference to specific embodiment further
Detailed description.
Single-sided polishing silicon chip：Buy in Tianjin Hedong District Jing Yifang electronic products business department, model：P-type, resistivity：
10-15Ω·cm.Crystal orientation：<100>±0.5°.Thickness：400μm.Alumina ceramic plate：Buy limited in the imperial electronics in Guangzhou north
Company, thickness：0.6mm, specification：20*25mm.Superhigh vacuum magnetron sputtering manufacturer：The limited public affairs in Shenyang scientific instrument development center
Department, model：DPS-type III ultrahigh vacuum facing-target magnetron sputtering system coating machine；Vacuum high-temperature tube furnace：Hefei section crystalline substance material technology has
The GSL-1400X single temperature zone horizontal vacuum tube furnaces of limit company production.Single-sided polishing silicon chip and alumina ceramic plate are entered first
Row cleaning：By single-sided polishing silicon chip or alumina ceramic plate in volume ratio 4:It is cleaned by ultrasonic in 1 hydrogen peroxide and the concentrated sulfuric acid
10min, then successively it is placed in ultrasound in acetone solvent, absolute ethyl alcohol, deionized water and is respectively washed 5-10min, remove surface
Greasy dirt and organic impurities, it is placed in thoroughly drying in infrared baking oven.
Embodiment 1
(1) in substrate surface (aluminium oxide ceramics) the magnetron sputtering interdigitated platinum electrode cleaned.With quality purity
As target, the argon gas that quality purity is 99.999 ℅ attaches 99.999 ℅ Pt metal as sputter gas in substrate surface
Template simultaneously sputters Pt, to form interdigital electrode.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputter operating air pressure
2.0Pa, sputtering power 90W, argon flow amount 24sccm, sputtering time 2min.Under experiment condition, sputtering a layer thickness is about
100nm Pt films.
(2) magnetron sputtering deposition W film material layer
Using the type ultrahigh vacuum of DPS- III to targets magnetic sputtering film plating machine, being made with the ℅ of quality purity 99.999 tungsten
For target, it is thin to sputter one layer of tungsten of plating on pure alumina wafer surface as sputter gas for the argon gas that quality purity is 99.999 ℅
Film.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputter operating air pressure 2.0Pa, sputtering power 90W, argon gas stream
Measure 45sccm, sputtering time 20min.
(3) crystalline growth of one-dimensional tungsten oxide nano
W film is completed from Hefei Ke Jing Materials Technology Ltd. GSL-1400X electron tubes type high temperature furnace apparatus to tie again
Crystals growth process, 1300 DEG C of the tube furnace maximum temperature.The substrate for being coated with W film is placed on to the high-temperature region of tube furnace, tube furnace
650 DEG C are raised to from room temperature, 3 DEG C/min of heating rate.Be passed through argon gas and oxygen in the process, flow be respectively 40sccm and
0.2sccm, it is 200Pa to control air pressure in stove.4 hours are incubated at 650 DEG C, then naturally cools to room temperature.Insulation terminates, and treats it
Room temperature is naturally cooled to, takes out sample.
(4) the conventional annealing processing of one-dimensional tungsten oxide nano
By obtained one-dimensional tungsten oxide nano in step (3), conventional annealing 2 is small under 450 DEG C of air ambients in Muffle furnace
When, from 20 degrees Celsius of heatings of room temperature, programming rate is 3 DEG C/min.
(5) the tungsten oxide nano ti coat on diamond after annealing
Reuse nanowire surface of the ultrahigh vacuum facing-target magnetron sputtering system equipment after step (4) processing and deposit one layer of gold
Belong to titanium film.Using the ℅ of quality purity 99.999 Titanium as target, the argon gas that quality purity is 99.999 ℅ is as sputtering gas
Body, one layer of titanium film of plating is sputtered on tungsten oxide nano surface.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputtering
Operating air pressure 1Pa, sputtering power 90W, argon flow amount 45sccm, sputtering time 3min.
(6) thermal anneal process of titanium
By the substrate after step (5) processing in Muffle furnace conventional annealing 2 hours under 450 DEG C of air ambients, from room temperature 20
Degree Celsius heating, programming rate is 3 DEG C/min.
Embodiment 2
The present embodiment and the difference of embodiment 1 are：The titanizing time is changed into 6min in step (5).
Embodiment 3
(1) in substrate surface (aluminium oxide ceramics) the magnetron sputtering interdigitated platinum electrode cleaned.With quality purity
As target, the argon gas that quality purity is 99.999 ℅ attaches 99.999 ℅ Pt metal as sputter gas in substrate surface
Template simultaneously sputters Pt, to form interdigital electrode.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputter operating air pressure
1Pa, sputtering power 100W, argon flow amount 25sccm, sputtering time 3min.Under experiment condition, sputtering a layer thickness is about
120nm Pt films.
(2) magnetron sputtering deposition W film material layer
Using the type ultrahigh vacuum of DPS- III to targets magnetic sputtering film plating machine, being made with the ℅ of quality purity 99.999 tungsten
For target, it is thin to sputter one layer of tungsten of plating on pure alumina wafer surface as sputter gas for the argon gas that quality purity is 99.999 ℅
Film.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputter operating air pressure 1Pa, sputtering power 100W, argon flow amount
40sccm, sputtering time 25min.
(3) crystalline growth of one-dimensional tungsten oxide nano
W film is completed from Hefei Ke Jing Materials Technology Ltd. GSL-1400X electron tubes type high temperature furnace apparatus to tie again
Crystals growth process, 1300 DEG C of the tube furnace maximum temperature.The substrate for being coated with W film is placed on to the high-temperature region of tube furnace, tube furnace
From room temperature, 25 degrees Celsius are raised to 660 DEG C, 1 DEG C/min of heating rate.Argon gas and oxygen are passed through in the process, and flow is respectively
45sccm and 0.2sccm, it is 180Pa to control air pressure in stove.2 hours are incubated at 660 DEG C, then naturally cools to room temperature.Insulation
Terminate, treat that it naturally cools to room temperature, take out sample.
(4) the conventional annealing processing of one-dimensional tungsten oxide nano
By obtained one-dimensional tungsten oxide nano in step (3), conventional annealing 2 is small under 350 DEG C of air ambients in Muffle furnace
When, from 25 degrees Celsius of heatings of room temperature, programming rate is 1 DEG C/min.
(5) the tungsten oxide nano ti coat on diamond after annealing
Reuse nanowire surface of the ultrahigh vacuum facing-target magnetron sputtering system equipment after step (4) processing and deposit one layer of gold
Belong to titanium film.Using the ℅ of quality purity 99.999 Titanium as target, the argon gas that quality purity is 99.999 ℅ is as sputtering gas
Body, one layer of titanium film of plating is sputtered on tungsten oxide nano surface.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputtering
Operating air pressure 1Pa, sputtering power 100W, argon flow amount 40sccm, sputtering time 4min.
(6) thermal anneal process of titanium
By the substrate after step (5) processing in Muffle furnace conventional annealing 1.5 hours under 400 DEG C of air ambients, from room temperature
20 degrees Celsius of heatings, programming rate is 2 DEG C/min.
Embodiment 4
(1) in substrate surface (aluminium oxide ceramics) the magnetron sputtering interdigitated platinum electrode cleaned.With quality purity
As target, the argon gas that quality purity is 99.999 ℅ attaches 99.999 ℅ Pt metal as sputter gas in substrate surface
Template simultaneously sputters Pt, to form interdigital electrode.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputter operating air pressure
1.5Pa, sputtering power 95W, argon flow amount 20sccm, sputtering time 1min.Under experiment condition, sputtering a layer thickness is about
80nm Pt films.
(2) magnetron sputtering deposition W film material layer
Using the type ultrahigh vacuum of DPS- III to targets magnetic sputtering film plating machine, being made with the ℅ of quality purity 99.999 tungsten
For target, it is thin to sputter one layer of tungsten of plating on pure alumina wafer surface as sputter gas for the argon gas that quality purity is 99.999 ℅
Film.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputter operating air pressure 1.5Pa, sputtering power 95W, argon gas stream
Measure 45sccm, sputtering time 20min.
(3) crystalline growth of one-dimensional tungsten oxide nano
W film is completed from Hefei Ke Jing Materials Technology Ltd. GSL-1400X electron tubes type high temperature furnace apparatus to tie again
Crystals growth process, 1300 DEG C of the tube furnace maximum temperature.The substrate for being coated with W film is placed on to the high-temperature region of tube furnace, tube furnace
From room temperature, 20 degrees Celsius are raised to 620 DEG C, 1 DEG C/min of heating rate.Argon gas and oxygen are passed through in the process, and flow is respectively
45sccm and 0.2sccm, it is 180Pa to control air pressure in stove.4 hours are incubated at 620 DEG C, then naturally cools to room temperature.Insulation
Terminate, treat that it naturally cools to room temperature, take out sample.
(4) the conventional annealing processing of one-dimensional tungsten oxide nano
By obtained one-dimensional tungsten oxide nano in step (3) in Muffle furnace conventional annealing 1.5 under 400 DEG C of air ambients
Hour, from 20 degrees Celsius of heatings of room temperature, programming rate is 2 DEG C/min.
(5) the tungsten oxide nano ti coat on diamond after annealing
Reuse nanowire surface of the ultrahigh vacuum facing-target magnetron sputtering system equipment after step (4) processing and deposit one layer of gold
Belong to titanium film.Using the ℅ of quality purity 99.999 Titanium as target, the argon gas that quality purity is 99.999 ℅ is as sputtering gas
Body, one layer of titanium film of plating is sputtered on tungsten oxide nano surface.It is 2 × 10 that body vacuum is kept in sputter procedure-4Pa, sputtering
Operating air pressure 1.5Pa, sputtering power 95W, argon flow amount 42sccm, sputtering time 5min.
(6) thermal anneal process of titanium
By the substrate after step (5) processing in Muffle furnace conventional annealing 1 hour under 450 DEG C of air ambients, from room temperature 20
Degree Celsius heating, programming rate is 1 DEG C/min.
The test of air-sensitive performance, the air admission hole set by sealing container top are carried out using structure as shown in Figure 11
Into sealing container, the micro tested gas of injection, passes through mini fan and the collective effect of gas outlet so that tested gas exists
Further spread in sealing container, make tested gas diffusion to being placed on the gas sensor element on heating platform, electronics
Controller unit controls the temperature of heating platform by temperature control wire in real time, and gas sensor element passes through sensing element wire
It is connected with the UT70D resistance detection equipment of excellent Leadd B.V, to the resistance value of real-time display probe junction, and will be corresponding
Resistance test data transfer is to computer terminal, by computer terminal by whole resistance test numerical value summary records into form.By Fig. 6
As can be seen that compared with pure phase tungsten oxide nano, optimum working temperature is down to 20-30 degrees Celsius of room temperature by 150 DEG C, hence it is evident that
Improve its best operating condition, this is beneficial to the integra-tion application of the gas sensor and reduces power consumption.Fig. 7-Fig. 8 is plating respectively
Gas sensor is to NO under the conditions of titanium different time2The dynamic response recovery curve of gas, unlike anticipation, adsorbed gas point
The resistance of sensor reduces after son, and it is not the n-type envisioned to illustrate the element, and n-p transoid phenomenons occurs.Can from Fig. 6
Go out, when temperature is increased to more than 50 DEG C, n-type be presented again, this should be hetero-junctions with room temperature optimal temperature conditions simultaneously in the presence of
Gas is caused to adsorb by force, and then enabled band overbending (intrinsic Fermi level is higher than n-type semiconductor fermi level, so as to transoid)
It is caused.Fig. 9 can be seen that sensitivity of three kinds of gas sensors under respective optimum working temperature rises with the increase of gas concentration
It is high.As shown in Figure 10, tungsten oxide/titanium oxide nucleocapsid heterogeneous structural nano linear array gas sensor can effective detection two at room temperature
Nitrogen oxide.
On the whole, instant invention overcomes simple tungsten oxide nano detection nitrogen oxides operating temperature height, sensitivity are low
The shortcomings that.Tungsten oxide nano is at 150 DEG C to 1ppmNO2The sensitivity of gas is 4.1, reaches highest.Prepared by the present invention
Heterogeneous sensing element is at room temperature to 0.5-5ppmNO2Dynamic response as shown in Figs. 7-8, made under the conditions of wherein titanizing 3min
It is standby go out one-dimensional nucleocapsid composite construction base gas sensitive device to 0.5ppm, 1ppm, 2ppm, 3ppm, 4ppm, 5ppmNO2The spirit of gas
Sensitivity is reacted：2.9th, 5.2,7.5,11.3,18.1,36.5, relative to the one-dimensional tungsten oxide nano of pure phase, performance improvement
Substantially.
The scheme recorded according to present invention carries out the adjustment of technological parameter, can prepare tungsten oxide/oxygen of the present invention
Change titanium nano wire and based on this formation gas sensor, show the performance basically identical with embodiment.
Exemplary description has been done to the present invention above, it should explanation, in the situation for the core for not departing from the present invention
Under, any simple deformation, modification or other skilled in the art can not spend the equivalent substitution of creative work equal
Fall into protection scope of the present invention.
Claims (10)
1. the gas sensor based on tungsten oxide/titanium oxide core-shell nano line, it is characterised in that compound by substrate, platinum electrode, tungsten titanium
Layer and tungsten oxide/titanium oxide core-shell nano linear array composition, platinum electrode is set in substrate, sets tungsten titanium compound on platinum electrode
Layer, tungsten oxide/titanium oxide core-shell nano linear array, tungsten oxide/titanium oxide core-shell nano linear array are set on tungsten titanium composite bed
It is made up of one-dimensional tungsten oxide/titanium oxide core-shell nano line in order, one-dimensional tungsten oxide/titanium oxide core-shell nano line in order, with oxidation
Tungsten is core, and using titanium oxide as shell, vanadium oxide, tungsten oxide/titanium oxide core-shell nano line length are equably wrapped up in the periphery of tungsten oxide
Spend for 800-1000nm, a diameter of 20-30nm of tungsten oxide, the thickness of titanium oxide is 10-20nm, tungsten oxide and titanium oxide shape
Into coaxial nucleocapsid heterojunction structure, nano-wire array is formed in substrate by one-dimensional tungsten oxide/titanium oxide core-shell nano line in order,
I.e. tungsten oxide/titanium oxide core-shell nano line is configured basically perpendicular to substrate surface, to form nano-wire array, macroscopical upper table
It is now membrane structure, tungsten oxide/titanium oxide core-shell nano line length is substantially consistent with film thickness.
2. the gas sensor according to claim 1 based on tungsten oxide/titanium oxide core-shell nano line, it is characterised in that oxygen
It is 850-1000nm to change tungsten/titanium oxide core-shell nano line length, a diameter of 25-30nm of tungsten oxide, and the thickness of titanium oxide is
10-18nm；Tungsten titanium composite bed thickness is 100-200nm, preferably 120-150nm.
3. the gas sensor according to claim 1 based on tungsten oxide/titanium oxide core-shell nano line, it is characterised in that platinum
Electrode is interdigitated platinum electrode.
4. the preparation method of the gas sensor based on tungsten oxide/titanium oxide core-shell nano line, it is characterised in that as steps described below
Carry out：
Step 1, using magnetron sputtering in substrate deposited metal platinum, as electrode, using Pt metal as target, with inert gas
For sputter gas, vacuum is kept to be less than 4 × 10 in sputter procedure-4Pa, sputter 1-2Pa of operating air pressure, sputtering power be 90-
100W, 20-25sccm of inert gas flow, sputtering time are 1-3min；
Step 2, using the type ultrahigh vacuum of DPS- III to passing through the deposited metal platinum of step 1 processing to targets magnetic sputtering film plating machine
Substrate on deposits tungsten film material plies, using tungsten as target, using inert gas as sputter gas, kept in sputter procedure
Vacuum is less than 4 × 10-4Pa, sputtering operating air pressure are 1-2Pa, sputtering power 90-100W, inert gas flow is 40-
45sccm, sputtering time are 20-25min；
Step 3, the W film prepared using vacuum high-temperature tubular type furnace apparatus to step 2 carries out crystalline growth tungsten oxide nano,
First oxygen in equipment is drained with inert gas, then is passed through the mixed gas of oxygen and inert gas as ambiance,
In tungsten oxide nano growth course, it is respectively 0.2sccm and 40-45sccm to control oxygen and inert gas flow, controls stove
Interior growth pressure is 180-200Pa, and tube furnace is raised to 620-660 DEG C from 20-25 degrees Celsius of room temperature, 1-3 DEG C of heating rate/
Min, 2-4 hours are incubated at 620-660 DEG C, then naturally cools to room temperature, takes out sample；
Step 4, the annealing of tungsten oxide nano, by tungsten oxide nano prepared by step 3 in 350-450 DEG C and air gas
Annealing insulation 1-2 hours under atmosphere environment, to promote the fully oxidized of tungsten oxide nano and stablize crystal orientation, naturally cool to afterwards
Room temperature；
Step 5, using vacuum high-temperature tubular type furnace apparatus prepared by step 4 and deposit gold on the tungsten oxide nano layer of the substrate of processing
Belong to titanium, using Titanium as target, using inert gas as sputter gas, keep vacuum to be less than 4 × 10 in sputter procedure- 4Pa, inert gas flow 40-45sccm, sputtering operating air pressure are 1-1.5Pa, sputtering power 90-100W, sputtering time
For 3-6min, preferably 4-5min；
Step 6, the thermal anneal process of titanium, the deposited metal titanium film substrate after step 5 is handled is in 400-450 DEG C and air atmosphere
Annealed 1-2 hours under environment, to promote to aoxidize and synthesize titanium oxide shell, naturally cool to room temperature afterwards.
5. the preparation method of the gas sensor according to claim 4 based on tungsten oxide/titanium oxide core-shell nano line, it is special
Sign is, in step 1, choice of the substrates single-sided polishing silicon chip, or alumina ceramic plate；Substrate is covered using electrode template,
So that metal platinum forms interdigital row platinum electrode in substrate；Purity using metal platinum is 99.999%；It is using inert gas
Nitrogen, helium or argon gas, purity 99.999%；The thickness of deposited metal platinum is 80-120nm；In step 2, using gold
The purity for belonging to tungsten is 99.999%；The use of inert gas is nitrogen, helium or argon gas, purity 99.999%.
6. the preparation method of the gas sensor according to claim 4 based on tungsten oxide/titanium oxide core-shell nano line, it is special
Sign is that in step 3, it is respectively 0.2sccm and 40sccm to control oxygen and inert gas flow, controls growth pressure in stove
For 180Pa；Tube furnace is raised to 630-650 DEG C for 20-25 degrees Celsius from room temperature, 1-3 DEG C of heating rate/min, at 630-650 DEG C
3-4 hours are incubated, then naturally cool to room temperature；Inert gas is nitrogen, helium or argon gas, purity 99.999%；Oxygen
Gas purity is 99.999%.
7. the preparation method of the gas sensor according to claim 4 based on tungsten oxide/titanium oxide core-shell nano line, it is special
Sign is that in step 4,20-25 degrees Celsius are heated up from room temperature, and programming rate is 1-3 DEG C/min.
8. the preparation method of the gas sensor according to claim 4 based on tungsten oxide/titanium oxide core-shell nano line, it is special
Sign is, in steps of 5, inert gas is nitrogen, helium or argon gas, purity 99.999%；In steps of 5, using gold
The purity for belonging to titanium is 99.999%.
9. the preparation method of the gas sensor according to claim 4 based on tungsten oxide/titanium oxide core-shell nano line, it is special
Sign is that in step 6, selection uses Muffle furnace, anneals 1-1.5 hours；In step 6, it is Celsius from room temperature 20-25
Degree is heated up, and programming rate is 1-3 DEG C/min.
10. the gas sensor based on tungsten oxide/titanium oxide core-shell nano line detects the application of nitrogen dioxide, its feature at room temperature
It is, room temperature is 20-30 degrees Celsius, and minimum detectable value is 0.5ppm.
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| CN109030578A (en) * | 2018-07-30 | 2018-12-18 | 清华大学 | A kind of NO based on the nano heterogeneous junction structure of CdTe/ZnO2The preparation method of gas sensor |
| CN109621854A (en) * | 2018-10-31 | 2019-04-16 | 青岛大学 | A kind of compound hollow microballoon preparation method improving triethylamine detection performance |
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| CN109709192B (en) * | 2018-12-14 | 2022-06-17 | 复旦大学 | Gas-sensitive nanomaterial based on tungsten oxide/tin oxide core-shell nanosheet structure, preparation process and application thereof |
| CN111217537A (en) * | 2020-01-13 | 2020-06-02 | 哈尔滨商业大学 | Preparation method of core-shell molybdenum trioxide @ tungsten oxide nanocrystalline electrochromic film |
| WO2024043806A1 (en) * | 2022-08-22 | 2024-02-29 | ДРАГАН, Константин | Sensing element of a sensor |
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