CN101142476A - Gated gas sensor - Google Patents
Gated gas sensor Download PDFInfo
- Publication number
- CN101142476A CN101142476A CNA200680008191XA CN200680008191A CN101142476A CN 101142476 A CN101142476 A CN 101142476A CN A200680008191X A CNA200680008191X A CN A200680008191XA CN 200680008191 A CN200680008191 A CN 200680008191A CN 101142476 A CN101142476 A CN 101142476A
- Authority
- CN
- China
- Prior art keywords
- semiconductor
- sensor
- characteristic
- layer
- sensor according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
An apparatus for sensing an analyte gas is provided. The apparatus may include a signal amplifier that may include a thin film transistor that may include a semiconducting film that may include a metal oxide capable of chemical interaction with the analyte gas, such as carbon monoxide. The apparatus may be tuned for detecting the analyte gas by varying the gate voltage of the transistor.
Description
About the research of federation's patronage or the statement of exploitation
U.S. government enjoys specific rights according to the Grant No.FA8650-05-M-6562 that air force authorizes for the present invention.
Technical field
The present invention relates generally to gas sensor.More particularly, the present invention relates to by applying the gas sensor that gate voltage is worked by the detection of the electric current of compound layer with adjustment, described compound can produce chemical interaction with analyte gas.In addition, can utilize other method to adjust the detection of analyte, described method comprises light stimulus, chemical dopant, surface chemistry layer and combination thereof.In addition, applying external force (such as grid bias) helps to eliminate or reduces demand to the heated substrates surface greatly.More especially, the present invention relates to be suitable for the film gate metal oxide detector of check and analysis thing gas (for example carbon monoxide).
Background technology
The metal oxide sensor of heating
The background information relevant with the metal oxide chemical sensor has a lot.These sensors all are placed on the substrate of heating or by Electrochemical Detection and measure.For example referring to Eranna, G. wait the people's, " OxideMaterials for Development of Integrated Gas Sensors-A Comprehensive Review " Critical Reviews in Solids State and Materials Sciences, 29:111-188,2004 and list of references wherein.
Desirable providing is used to detect the particularly sensor of harmful gas of the gas that is under the ambient level.Metal oxide sensor to heating has carried out sufficient research in the literature.As nearest commentary, in the document of people such as Eranna (table 23, is known as list of references 1 in this article by the 174th page), provided detectable gas scope and for the metal oxide of every kind of gas sensitization.The inventor is verified to have made multiple improvement for the ability of utilizing the metal oxide surface probe gas.
Many metal oxides have characteristic of semiconductor.This means between the electron population that is known as valence band and conduction band to have energy gap, at the removable material that passes through of these electronics of described energy gap place.This energy gap is commonly referred to as band gap and by E
gExpression.Metal oxide sensor has utilized the advantage of this characteristic of semiconductor by impel electronics by means of heat from valence band guide Tape movement.This thermal excitation that electronics is carried out can change the surface energy of metal oxide, is easy to carry out chemical reaction thereby impel.
Metal oxide has the metamict crystals structure usually.This means to have single crystal grain, but can not have long-range order towards the surface.Interface between each intergranule has formed crystal boundary.The conduction of being undertaken by metal oxide is subjected to the restriction of the energy barrier that forms at each crystal boundary place.Except the variation of surface energy, heat has also changed the energy level of the energy barrier that forms at these independent crystal boundary places.
As a particular instance, the limitation that the present residing state of detection that carries out in the detection that we look at carbon monoxide (CO) is carried out, this area and their exist.Anthracemia is a major issue that all exists in civilian department and the military department.In the U.S., estimate to have every year 500 people of surpassing owing to the unexpected carbon monoxide (" CO ") of dying from is poisoned, this numeral recently all wants many from the numeral of any other Toxic.In addition, estimate to have every year 10,000 people to receive treatment owing to carbon monoxide exposes the symptom that causes occurring.Although great majority can be identified and be handled in the accident relevant with CO that family takes place, for the aircraft environment that lacks suitable supervising device easily, situation can be even more serious.
Compare with oxygen, carbon monoxide is about 210 times of oxygen to the affinity of haemoglobin.CO is the gas that a kind of scentless insipidness does not have color yet, and described gas can cause occurring the symptom of anemic hypoxia, and described symptom shows as the reduction of blood oxygen carrying capacity.Carbon monoxide in the blood has formed carbonyl hemoglobin (COHb), thereby has stoped the picked-up of oxygen.Sea level elevation place on the sea level, the increase of COHb level causes occurring from headache to senseless various symptoms.Height place on the sea level, the CO of 200ppm can cause occurring the symptom (content that is equivalent to the COHb in the health is 15-20%) of headache.At higher sea level elevation place, CO poisons and the effect of high altitude anoxia can build up, and makes and need carry out continuous low-level monitoring to the CO that is lower than the 200ppm level in the passenger cabin.
In the past during the decade, multiple metal oxide and electrochemical sensor are used in the family expenses CO detection alarm device, but these sensors all be not accurate to can be continuously and measure the degree that is in the CO under the lower ppm level exactly.Monitor the carbon monoxide that is under 35 to the 200ppm levels continuously any commercial available CO detector technologies has been proposed challenge.Continuous carbon monoxide monitoring all is very crucial in family, industry and military department.At present, the technology that is used to make the carbon monoxide warning horn has three kinds.The relative merits of every kind of method have been enumerated below.
Carbon monoxide (CO) detecting device based on the metal oxide that heats:
The sensor utilization of based semiconductor be the tin dioxide thin film that is positioned at the heating on the ceramic substrate.CO is oxidized on the high temperature surface.Owing to being exposed to carbon monoxide, tin ash make electric current increase.The electron device of microchip control detects the variation of electric current and will give the alarm when the level of the CO that records by described electric current exceeds predetermined threshold.These sensors are being worked above under 400 ℃ the high temperature, thereby become the factor that causes high power consumption.This high temperature makes described sensor be easy to occur the rub-out signal that is produced by chemically similar analyte.The advantage of this sensor is as follows: cheap and be easy to produce.The shortcoming of this sensor is as follows: the power consumption height, and cycling time is slow; Oxygen contamination; Be easy to occur the false positive signal; And need heating so that make system regeneration.Above-mentioned technology still is not enough to solve fully the problem that continuous detecting is in the carbon monoxide in the lower ppm scope.
Molybdenum oxide (the MoO of heating
3) the CO sensor.
Therefore, continue other optional sensor is studied.For example, in the performance history of CO sensor, adopted the molybdenum oxide (MoO for preparing by collosol and gel and radio frequency (RF) magnetron sputtering technique in the past
3) film, as " Carbon Monoxide response of molybdenum oxide thin filmsdeposited by different techniques; " by E.Comini, G.FagIia, G.Sberveglieri, C.Cantalini, M.Passacantado, S.Santucci, in Sensors and Actuators B 68, described in the pp.168-174 (2000) like that, the document is known as list of references 2 in this article.The radio frequency deposited film has acicular texture, and the longitudinal size of described acicular texture is in the scope of 200-400nm.Be applied on the sensed layer and with picoammeter record resistance and response is measured by constant potential 1V.This CO sensor is as the chemical impedance sensor.Fig. 8 of list of references 2 show be in 300 ℃ under the temperature the collosol and gel sensor and the radio-frequency sputtering sensor to the dynamic response of the square wave concentration impulse of 30ppm CO.The electric current shown in Figure 8 of list of references 2 changes the micromicro scope that is in.The shortcoming of this scope is, for continuous watch-dog, under the situation of the very complex apparatus of not utilizing inconvenience to take, tends to may write down so faint output hardly.Sensor in the list of references 2 is worked under 300 ℃ temperature.A large amount of electric power that added heat rejection that sensor base plate is carried out.This is disadvantageous for portable unit.
Further continue the method for research depositing metal oxide.For example, " Size-selectiveelectrodeposition of meso-scale metal particles:a general method; " by H.Liu, F.Favier, K.Ng, M.P.Zach, R.M.Penner, in Electrochimica Acta 47 pp.671-677 (2001)) author confirms that can utilize pulse volt-ampere technology to grow molybdenum dioxide dispersed nano particle on conduction surfaces, described document is known as list of references 3 in this article.Fig. 5 of list of references 3 shows the scanning electron micrograph that is positioned at the lip-deep molybdenum dioxide metal nanoparticle of graphite base portion.As shown in this Fig, nano particle has the apparent size of 100-200nm, and is indicated as 1 micron scale mark.Also may the existing metal film of oxidation.
Although the instruction above having had, but but still be starved of other selecting technology of the metal oxide sensor of heating.Particularly, still need to have low-power requirements, the gas sensor of wide environmental work scope, fast response time, high selectivity and hypersensitivity.
Summary of the invention
The inventor has been found that any known metal oxides sensor of working owing to heat activation can preferably not have to come work by using other optional energy-activated method under the situation of thermal excitation.Use other optional ENERGY METHOD the surface energy state of metal oxide and the similar variation of conduction mechanism are provided.For example, in thin film transistor (TFT) (TFT) structure, apply the heat demand that grid bias have been eliminated described sensor.It is how can control the surface energy of metal oxide and change energy barrier by crystal boundary that Fig. 1 shows grid bias.In addition, motivational techniques can be light stimulus, magnetic pumping or its combination.
In certain embodiments, the detection mechanism of above-mentioned metal oxide sensor and working temperature are irrelevant.In more such embodiment, the passage with characteristic of semiconductor is controlled in the electronics mode.As an example, sensor is being worked under the condition of 60F and 140F under the identical grid bias.
Thin-film transistor structure can comprise the film with characteristic of semiconductor, and described film comprises and can produce chemically interactive compound with analyte gas.Described compound is metal oxide preferably.Chemical interaction is electron transport preferably.Therefore, according to one embodiment of present invention, gas sensor comprises metal oxide.Described metal is transition metal preferably, is more preferably 6B family element, further molybdenum preferably.
The inventor has been found that the intrinsic signal amplification characteristic of thin film transistor (TFT) (TFT) structure has overcome the faint problem of output of the sensor that is used for check and analysis thing gas.
Further, in combination or another kind of optional mode be that according to one embodiment of present invention, a kind of gas sensor is worked by carrying out electron transport from analyte gas.This electron transport can be the result of the catalytic reaction of carrying out on the surface of described sensor.Electron transport can be power supply.Another kind of optional mode is that electron transport can be electrophilic.Analyte gas is carbon monoxide preferably.
Further, in combination or another kind of optional mode be that according to one embodiment of present invention, a kind of gas sensor comprises the sensor construction that utilizes metal oxide semiconductor.In described sensor construction, the form that metal oxide can film exists.For example, metal oxide can nano particle or the form of nanoparticle network exist.Described sensor construction preferably includes thin-film transistor structure.
Again further, in combination or another kind of optional mode be that according to one embodiment of present invention, a kind of gas sensor comprises at least a metal oxide nanoparticles of making by growing method.Can be by first plated metal, with the described metal of rear oxidation film is grown on the spot.The metal level growing method can comprise electrochemical growth, sputter, evaporation of metal, solution-treated (comprising collosol and gel and nanoparticles solution).The layer metal deposition method can be the combination of above-mentioned technology.After depositing metal layers, need carry out the oxidation of subsequent technique, metal is changed into its corresponding metal oxide.Can hot mode, chemical mode, electrochemical means or its array mode implement this oxidation.Can be by the electric conductivity of grain boundary interfaces control by this metal oxide film.
Again further, according to one embodiment of present invention, a kind of gas sensor comprises microprocessor.
Further, the present invention relates to the gas sensor of working: apply external force,, and change the electrical transmission that has the layer of characteristic of semiconductor by described so that the surface energy that has a layer of characteristic of semiconductor by change adjusts sensor by following measure.Can realize adjustment by applying grid to surface energy.In addition, can utilize other method to adjust the detection of analyte, described method comprises light stimulus, chemical dopant, surface chemistry layer, magnetic field and combination thereof.In addition, applying external force (for example grid bias) helps to eliminate or reduces demand to the substrate surface of heating greatly.
Further, according to one embodiment of present invention, a kind of gas sensor comprises the radio frequency integrating device that is used for remote sensing.
Any one embodiment according to the abovementioned embodiments of the present invention, described gas sensor can be used as quantimeter.
Therefore, according to one embodiment of present invention, a kind of gas sensor that is used for check and analysis thing gas can comprise first contact, second contact, the layer with characteristic of semiconductor, insulation course, substrate and the 3rd contact.Described the 3rd contact is preferably used as gate contacts.Described gate contacts can be a substrate.Described layer with characteristic of semiconductor preferably includes and can produce chemically interactive compound with described analyte gas.The preferably electron transport of described chemical interaction.Described insulation course, described layer, first contact, second contact and the 3rd contact with characteristic of semiconductor preferably are disposed on the predetermined structure, so that described sensor is with the electric current variable of variable detection for taking place between described first contact and described second contact when between described compound and described analyte electron transport taking place of described analyte gas (being denoted as for example CO) level.In this embodiment, CO is oxidized to carbon dioxide (CO
2).When this reaction took place, electronics was entered in the metal oxide surface by transmission from CO.When on described first contact and described the 3rd contact, applying gate voltage, can help the carrying out of this electron transport.When on described first contact and described the 3rd contact, applying gate voltage, can control the transmission of the electronics (or hole) that between described analyte and compound, produces by this electron transfer reaction.The reason of may command electric transmission may be the energy barrier height that has changed the grain boundary layer place between the nano particle.Apply grid bias can reduce the heat demand of sensor and allow under the situation that does not have outside or inner heated substrates in room temperature be lower than under the temperature of room temperature and move.
Further, according to one embodiment of present invention, a kind of gas sensor can comprise signal amplifier, and described signal amplifier comprises thin film transistor (TFT), described thin film transistor (TFT) comprises the film with characteristic of semiconductor, and described film with characteristic of semiconductor comprises molybdenum oxide.Described signal amplifier can be the external signal amplifier.Described signal amplifier can be the film crystal tube sensor.
The accompanying drawing summary
In order to understand the present invention and advantage thereof more fully, now in conjunction with the accompanying drawings with reference to following description, in described accompanying drawing:
Fig. 1 shows by applying the situation that grid bias are adjusted the reacted surface energy and depended on the electric transmission of crystal boundary;
Fig. 2 shows one embodiment of the present of invention;
Fig. 3 is the curve map of the susceptibility of amplifying based on gas sensor inside according to an embodiment of the invention;
Fig. 4 shows the metal oxide sensor structure of band grid;
Fig. 5 is used to make with the synoptic diagram of substrate as the additional procedure of processing of the gas sensor of the 3rd gate contacts according to one embodiment of present invention;
Fig. 6 is the synoptic diagram that is used for the gas sensor of remote application according to an embodiment of the invention;
Fig. 7 is the response curve of representative gases sensor according to an embodiment of the invention; With
Fig. 8 is another response curve of representative gases sensor according to an embodiment of the invention.
Detailed description of preferred embodiment
Referring now to Fig. 1,, Fig. 1 shows the adjustable of sensor.Figure 1A shows the surface topography that is exaggerated of the metal oxide between two contacts.Metal oxide and contact thereof are present on the top of the insulation course that separates the 3rd contact.This surface topography has formed crystal boundary, and at described crystal boundary place, the conduction in electronics or hole is subjected to the domination from a crystal grain to the energy barrier of adjacent crystal grain.Referring now to Figure 1B,, we can see, have the energy barrier that is associated with the crystal boundary shown in Figure 1A.In this embodiment, we can adjust conduction by metal oxide layer.This is to realize by the energy barrier height that changes each crystal boundary place.When take place surface reaction for example CO be oxidized to CO
2Oxidation reaction the time, the electronics that is transmitted is trapped near the reaction site between these energy barriers.The example of front shows that high heat can provide the energy that is enough to this electric transmission is crossed energy barrier.In this embodiment, the inventor reduces the energy barrier height by electrical bias is applied on the contact 3, eliminated the demand to heat thus.Referring to Fig. 1 C, how the inventor can adjust surface reaction by the figure shows.In Fig. 1 C, metal oxide has characteristic of semiconductor and has band gap.This band gap is to promote electronics to enter the energy of conduction band from valence band.The example of front is verified, needs high heat so that form suitable electron distributions in valence band and conduction band, thereby makes generation surface reaction such as CO be oxidized to CO
2Oxidation reaction.In this example, by applying grid bias the electron distributions in valence band and the conduction band is adjusted.
Referring now to Fig. 2,, gas sensor example shown in Figure 2 shows a kind of gas sensor that is used for check and analysis thing gas, described gas sensor comprises first contact (being denoted as for example metal contact pad), second contact, has the layer (being denoted as for example layer of metal oxide nanoparticles) of characteristic of semiconductor, insulation course (being denoted as for example dielectric insulator), substrate (being denoted as for example Si grid) and with the 3rd contact (not shown) of substrate contacts.The 3rd contact is preferably used as gate contacts.Layer with characteristic of semiconductor preferably includes and can produce chemically interactive compound with analyte gas.Still referring to Fig. 2, and as described further below, insulation course, the layer with characteristic of semiconductor, first contact, second contact and the 3rd contact preferably are disposed on the predetermined structure, so that described sensor is with the conduction variable of variable detection for taking place between first contact and second contact when applying gate voltage on first contact and the 3rd contact of analyte gas (being denoted as for example CO) level.
This as a kind of typical gas sensor disclosed be, a kind of based on the quick CO sensor of response of the compact low power that is applied to the structural metal oxide nanoparticles net of thin film transistor (TFT) (" TFT ").Some metal oxide is the n N-type semiconductor N, and described n N-type semiconductor N is owing to the electron transport due to the oxidation of analyte gas or the reduction demonstrates the increase that electricity is led.There are proportionate relationship in the variation that electricity is led and the concentration of analyte gas.Compare with the most of successful commercial technology based on the CO detecting device of metal oxide film, the scheme of nanoparticle network makes significant improvement aspect susceptibility and the selectivity, and this is owing to underlying cause causes.The interaction of the nanostructured of metal oxide nanoparticles net provides with commercial detecting device and has compared higher susceptibility.Work in lower ppm scope (for example 0-200ppm) becomes possibility, and can't realize in this commercial detecting device that is operated in based on thick SnO 2 thin film.Further, can the metal oxide nanoparticles net be upgraded by ambient oxygen.Further, the thin film transistor (TFT) design makes and can improve susceptibility owing to intrinsic advantage.This advantage stems from the curve characteristic of semi-conductive non-linear current to voltage.Again further, the device that the is proposed improved prominent feature that is better than prior art comprises following advantage: the intrinsic advantage that realizes by thin-film transistor structure; Chip-scale design and integrated; Respond fast and continuous monitoring; Intrinsic renewal by chemical property and gate voltage realization; Quantitative response; And the time integral response that is applicable to cumulative exposure.Can utilize the CMOS job operation to make thin-film transistor structure, so that realize the low cost manufacturing of massive parallel.
Apply the susceptibility of the ability controllable device of bias voltage.Previous work [the Fan that is undertaken by people such as Fan, Z. wait the people, " ZnO nanowires field-effect transistor and oxygen sensing property " Appyl.Phys.Lett.2004, (85) 24,5923-5925 is known as list of references 4 in this article] discussed a kind of lambda sensor of making by zinc paste (ZnO) nano-wire field effect transistor.This work shows, device changes to the susceptibility of the oxygen function as grid bias.Yet there are fundamentally different in the work of this device and the present invention.This device in, oxygen by physisorption to the ZnO surface.Oxygen adatom (adatom) is electronegative and removed the electron density on the semiconductor, thereby has changed the distribution of charge carrier.The variation of this carrier concentration can take place equally, and the variation of described carrier concentration is to be changed by the electric current that field effect causes with regard to defining when grid bias are applied on any semiconductor.This previous device is worked as chemical field-effect transistor (ChemFET).Their device will can not worked under environmental baseline, and it is saturated that reason is can the surface to occur under the normal oxygen concentration condition.This device is not a sensor, and just because environmental change causes transistorized response to produce physical change.
The present invention works by the chemical reaction that carries out at the metal oxide surface place.These chemical reactions can add electronics (by oxidation) or remove de-electromation (by reduction) from described layer with characteristic of semiconductor on the layer with characteristic of semiconductor of sensor.The variation of electron amount will change the electric current by device.Even if material is bad semiconductor, but removing of electronics will always can cause electric current to change, and the oxygen absorption that changes electron density or distribution then can not.
Before this, Dalin[Dalin, J. " Fabrication and characterization of a novel MOSFET gassensor " Final Thesis at Linkopings Institute of Technology, Frauhofer Institute forPhysical Measurement Techniques, Frieburg, Germany, 6-5-2002, LiTH-ISY-EX-3184, described document is known as list of references 5 in this article] show that grid bias can be adjusted the tin oxide (SnO that works by under 200 ℃ or 280 ℃ of temperature
2) electric current of gas sensor.This is a kind of sensor of heating.Although change has taken place the levels of current by sensor, susceptibility can not change.For example, Fig. 6 .5 of list of references 5 shows the relation of the CO of actual current value and variable concentrations under variable grid bias.The figure shows marked change in the current-responsive generation of each grid bias lower sensor.In Fig. 6 of list of references 5 .6, the SnO of heating
2Sensor is denoted as initial current rather than actual current to the response of CO.In the figure, as the function of grid bias, susceptibility has measurable but less variation.If the variation to response is checked, can see that then the baseline of response change is approximate identical with the response of exposure.This shows that grid bias have changed the levels of current by sensor, but does not increase susceptibility.The sensor of list of references 5 is not worked under lower temperature.
The work of gate metal oxide sensor of the present invention does not need heat.This gate metal oxide sensor is being worked in greater than 100 ℃ temperature range from-60 ℃.This sensor confirms that the response under low temperature more increases.
Technical method-chemical property
For the present invention, the chemical property of metal oxide is to survey the driving force of the electron transport that the surface reaction owing to analyte gas takes place.Analyte gas includes, but is not limited to, the species of carbon monoxide (CO) and other power supply and/or reception electronics.The success of sensor need produce maximized semiconductor response in metal oxide.Any metal-oxide film/nano-granular system is considered suitable for the present invention, but more particularly, utilizes for example molybdenum oxide (MoO of transition metal oxide
3), reason is that there is unique character in this transition metal oxide for CO.Metal oxide exists in a variety of forms.For example, molybdenum oxide can be MoO, MoO according to the state of oxidation of metal
2, MoO
3The present invention quotes MoO
3As particular instance, but the present invention can be applicable to other oxide of molybdenum.MoO
3Be will be by the n N-type semiconductor N of electron transport oxidation CO, described electron transport causes resistance to produce measurable variation.Molybdenum trioxide comprises the molybdenum of hexavalent state.There is not electronics in the molybdenum of hexavalent state on its 4d track.The result is, the oxidation of carbon monoxide comprise electronics from CO to Mo
+ 6The electron transport that takes place.After having carried out this initial electron transport step, may there be many response paths so that make carbon monoxide be oxidized to carbon dioxide subsequently.Most probable ground, these paths comprise free radical chain step fast, and this correspondingly changes into fast response transducer.
The present invention includes, but be not limited to, the nano particle of molybdenum oxide detects so that carry out CO.Molybdenum oxide has and is applicable to some peculiar property of the present invention.Other metal oxide can use with the solid state sensor design, but they do not have the character that is equal to molybdenum oxide.Two kinds of metals in addition in the 6B family element are chromium (Cr) and tungsten (W).They have the chemical property similar to molybdenum oxide.Element (the CrO at periodic table top
3) will have more reactivity.This reactivity can be brought certain cost.Have more reactive species and will form more stable product, make reaction reverse the difficulty that sensor upgrades even this has increased.Reactive increase also will reduce Selectivity of Sensor.On the contrary, be positioned at the element (WO of this family element column bottom
3) will have lower reactivity, this has reduced susceptibility but feasible being easier to reversed.Molybdenum oxide combines the highest reactivity and the performance that is easy to reverse most.Metal oxide beyond the 6B family does not confirm to have required susceptibility or the selectivity to CO.This also comprises tin ash.
It is not problem for the sensing system that is proposed that chemistry disturbs as water vapour.In the vehicles or in industry or home environment, exist other may pollutant such as carbon dioxide, nitrogen dioxide or stable hydrocarbon estimate can not produce to disturb to this sensing system.They will can be by electron transport and MoO
3Bonding takes place and therefore can not produce signal.Design a kind of for specific analyte have specificity and optionally metal oxide materials be possible.Simultaneously, a kind of eliminating of design is possible to the metal oxide materials of the susceptibility of specific analyte.In addition, the grid bias that are applied on the metal oxide materials can strengthen the selectivity at the analyte that chemically has similarity.
Compare with the nano particle of other pattern, use the ball shaped nano membrana granulosa to have many good qualities.The ball shaped nano particle has the active surface atom (diameter is in the scope of 5-300nm) that number percent increases.The atom that is in the particle center is known as " body (bulk) ", and these atoms do not promote the generation of any reaction or bonding process on electronics.When reacting or during bonding process, these surface atoms have bigger promotion meaning to total electronic structure of nano particle.The increase of this promotion meaning directly changes the increase of signal into.Class ball shaped nano particle has the ratio of similar surface and body.This will comprise nanometer " projection (bump) " that is positioned on the substrate or the little crystal grain that is positioned at lip-deep material.In addition, the film as thin as a wafer of metal oxide will be owing to having the susceptibility that high surface and the ratio of body demonstrate increase.For the specific material with characteristic of semiconductor, maximum susceptibility will appear under the situation that thickness is similar to debye (Debye) length; But also must consider total conduction.
The thin film transistor (TFT) sensor design:
Because MoO
3Have characteristic of semiconductor, so the present invention has adopted thin film transistor (TFT) (TFT) structure so that the signal output maximization of CO sensor.Molybdenum oxide is a n N-type semiconductor N material.This means and to control conductive process by the three-terminal contact that is commonly referred to as grid by material.Because described molybdenum oxide is the n N-type semiconductor N, therefore when we transfer to adopt positive gate voltage, resistance will be reduced.Because CO is oxidized to CO
2And the electron transport that causes producing will increase MoO
3Therefore electron number in the film increases the quantity of charge carrier and has increased electric current by device.This is identical with applying positive gate voltage on effect.
Refer again to Fig. 2, Fig. 2 shows and is used to carry out the metal oxide semiconductor films transistor that CO detects.When on the surface of CO at metal oxide when oxidized, electron transfer process takes place.This surface reaction has changed the carrier concentration of n N-type semiconductor N and as the variation of electric current and measured reflecting.
MoO
3Characteristic of semiconductor promoted the increase of sensor sensing.There is intrinsic advantage in thin-film transistor structure, that is to say, the variation that the minimum variation that gate voltage produced (for example owing to the oxidation of CO causes the electron transport that takes place) has produced electric current.Fig. 1 shows oxidation owing to gas (as CO) and cause the electron transfer process of carrying out that takes place in the metal oxide nanoparticles framework.As shown in Figure 1, the electric current variation that this electron transfer process causes taking place can reach several magnitude, and this depends on the slope of electric current and gate voltage curves.This curve is based on that n N-type semiconductor N material draws.Can the present invention be used for reducible gas by channel semiconductor is made the p type.In such device, the surface will provide electronics so that allow the chemical species of oxidation to be reduced.The variation that takes place to the p type from the n type will need by changing base metal, adopting the alloy of other metal or a small amount of additional materials that mixes changes the chemical property of metal oxide.
Referring now to Fig. 2,, Fig. 2 shows the relation curve of electric current and grid voltage for the n N-type semiconductor N, as shown in the figure, owing to making the less variation (Δ V) that gate voltage takes place, the electron transport that takes place from CO can cause electric current that bigger intrinsic variation (Δ I) takes place.
As shown in Figure 2, less variation takes place in the mobile gate voltage that only needs of ordering to B from the A point.Therefore, less change in voltage can cause electric current to have greatly changed (near three orders of magnitude), has strengthened intrinsic property (Δ V/ Δ I) thus.The amplification of sort signal allows to occur the unmatched situation of sensitivity levels, and this can't realize in the chemical impedance sensor.In addition, to the control permission sensor slope place that promptly install in the most responsive zone in the I-V curve work of gate voltage, and the susceptibility steepest that therefore installs.
Can by a kind of comprise as described below with MoO
3Nano particle is deposited on method on the conductive substrate and the film processed transistor arrangement with electrochemical means.Further, can pass through the solution methods depositing metal oxide.Further, can grow by making the oxidized metal oxide that makes of thin metal film or metal nanoparticle film.
The inventor has envisioned that two kinds of parallel scheme of Gamry potentiostat and PC interface make nanoparticle growth by for example utilizing.In scheme I, technology comprises nano particle directly is deposited on the conductive substrate that the surface portion with conductive substrate changes insulation course into subsequently.In scheme I, this two process comprises removes nano particle with non-directly being deposited on the conductive substrate and from conductive substrate of nano particle, subsequently with nanoparticle deposition on insulated substrate.Although the mode by example directly and directly deposits the mode that is described as electrochemical growth with non-, should be appreciated that, also envisioned other optional deposition process known in the art, for example sputter, thermal evaporation, electron beam evaporation and similar method.Further, according to this deposition process, generation embryo deposit process on conductor, insulator and the semi-conductive any suitable surface can be selected from.
Procedure of processing:
1, scheme I: the electrochemical growth of metal oxide nanostructure:
Referring now to Fig. 3,, Fig. 3 shows and is used to form based on MoO
3The electrochemical processing step of the CO sensor of thin film transistor (TFT).In steps A, nano-particular film is deposited on the Si substrate with electrochemical means.In step B, gate oxide is grown with hot mode.
Still referring to Fig. 3, the inventor will begin and make the nano particle direct growth from the conduction silicon substrate, until obtain conductive membranes in step B.Silicon substrate will be finally as spherical back of the body grid.To implement to make with electrochemical means the process of metal oxide nanostructure by the technological process of two steps, the technological process of described two steps comprises nucleation step (applying higher negative voltage in＜10 seconds short period) and the long-time growth step of implementing (reaching 10 minutes) under lower negative voltage in aqueous solution/organic metal oxide solution.Can constant voltage mode (chronoamperometry) or implement electrochemical fabrication process with constant current mode (chronpotentiometry).
After electrochemical growth, thermal oxide will be carried out so that make Si oxide below layer of molybdenum oxide, grow (step B).This hot step of 1000 ℃ will play two kinds of effects.At first, this step will produce the hot gate insulation layer of high-quality monox, and avoid photolithographic alignment issues.Secondly, thermosphere will make the molybdenum oxide film with characteristic of semiconductor be subjected to annealing in process so that increase conduction.Higher conduction will alleviate the needs for complex electronics, thereby eliminate the noise that occurs when measuring low current signal.Another kind of optional mode as this mode of this metal oxide of Direct Electroplating also can adopt second kind of parallel scheme.
2, scheme II: the non-Direct Electrochemistry growth of metal oxide nanostructure:
The present invention will comprise a kind of technological process, and wherein molybdenum oxide will be gone up nucleation and growth in conductive substrate (for example fresh graphite surface that splits), remove nano particle and will collect liquid phase from conductive substrate subsequently.This will allow we with the solution deposition mode with nanoparticle deposition to any insulated substrate.We will utilize drop coating or form the conductive nano membrana granulosa based on the technology of Langmuir-Blogett solution.These two kinds of technology all are the technology that known being used to deposits continuous nano-particular film.Fig. 4 shows these technology.In case form the molybdenum oxide film, then we will advance to the resulting device process.
Refer again to Fig. 4, Fig. 4 shows and is used to form based on MoO
3The non-Direct Electrochemistry procedure of processing of the CO sensor of thin film transistor (TFT).In steps A, nano-particular film is deposited on conduction (for example graphite) substrate with electrochemical means, gather in the crops step subsequently, in described results step, nano particle is dispersed in the liquid phase suspension.Nano particle can be deposited on the insulated substrate as drop coated film or Langmuir Blogett film subsequently.
3, scheme III: behind plated metal, carry out oxidation.
The present invention can comprise a kind of technological process, and wherein molybdenum is deposited on the substrate.Can utilize liquid phase suspension, thermal evaporation, sputter, electron beam evaporation or this metal level of other deposition techniques as known in the art of metal nanoparticle.This metal level will be deposited on the insulated substrate, be oxidized to metal oxide subsequently.Can make metal level oxidized by in aerobic environment, heating.Control temperature and oxidization time will be controlled the conduction of metal level.Metal can be oxidized under the temperature between 100 ℃ and 1400 ℃.All right chemical mode of metal or electrochemical means are oxidized.In case form this metal oxide layer, then we can proceed final processing.
4, the final lithographic process steps and the assembling of device:
Referring now to Fig. 5,, Fig. 5 shows MoO
3The photolithographic steps of CO sensor.
After finishing scheme I, II or III, be necessary to take a plurality of additional steps so that finishing device.Refer again to Fig. 5, will utilize the photoetching of standard and the first hard contact electrode evaporation that lift-off technology (step C) will form source electrode and drain electrode to MoO
3On the film.These contacts will be used to measure electric current or the resistance by the active region of device.Next, will utilize the photoetching process shown in step D that composition is carried out in the active region of device.Photoresist will be formed on the diaphragm that uses in the subsequent reaction ion etching step.In this etching step, will remove molybdenum oxide from the undesired zone on the chip, prevent between adjacent sensor to take place string around, and limit the size of actual resulting device.In final step, will perforate in the insulating oxide silicon layer, metallize subsequently so that allow the substrate contacts (shown in step e) of grid and bottom.After the processing of finishing wafer, this wafer will be split into independent sensor element.Subsequently, will utilize suitable epoxy that sensor is installed on many pin row pins.To utilize subsequently method for packing well known by persons skilled in the art with three contacts (source electrode, drain and gate) wire bond to header pin.
The exploitation of microprocessor and device integrated:
The microprocessor that develops as a part of the present invention will have control-grid voltage, measure electric current, the calculating CO concentration by our CO sensor and drive digital indicator and export to the ability of warning horn.The casing of device may comprise based on the audible alarm of piezoelectric structure and based on the visible alarm of light emitting diode.Microprocessor need move under the situation more than an input channel.The inertia reference sensor will be included in the device so that eliminate drift phenomenon aging and that temperature is brought.To during each sampling period, measure the reference channel together with activity sensor.Data sample averages out so that filtered noise and change into the CO concentration level.Airborne LCD with per 20 seconds or at interval shorter time with regard to lastest imformation.
Referring now to Fig. 6,, Fig. 6 shows radio frequency (RF) integrating device that is used for remote application.
The structure of this device will be fully compatible so that carry out remote reading with the low-power radio frequency link.Refer again to Fig. 6, Fig. 6 shows a kind of possible layout.Software performance will be tackled normally the variation of " I am in running " state and battery status report and survey measurements.Adopt the work period of about 0.1% duty cycle so that report the variation of the CO that takes place with about 10 seconds interval.This makes the total power consumption that takes place with 0.1% interval be maintained at about 2mW.This low average power consumption makes it possible to realize long battery life.
To be easier to fully understand the present invention by following example.What this example was represented is gas sensor according to an embodiment of the invention.
Example
Prepare sensor by making in the film of a part that is arranged to thin-film transistor structure, to grow as the molybdenum trioxide of typical detection of compound.This growth is by carrying out electron beam evaporation, subsequently molybdenum being carried out thermal oxide and carry out to molybdenum.Utilize the feature of scanning electron microscope (SEM) observation membrane structure.Film has nanoparticle structure.The metal film of deposition has the thickness less than 20nm.
Fig. 7 shows the response of sensor to the continuous carbon monoxide stream of the 50ppm of closed chamber inside.Sensor is at room temperature worked.This response is the function as the time, the resistance R under the resistance R under the situation that carbon monoxide exists and the situation that does not have carbon monoxide
0Normalized ratio record.Determine two different gate voltage value+5V and-this response under the 5V.What be labeled as that the line of ON and OFF represents is the state that the dosage of CO is opened and closed.Above curve (5Vg) expression is response to CO.Below curve (+5Vg) expression is to the response of CO.The result confirms, can adjust the response of sensor by changing gate voltage.
Fig. 8 shows the response of identical sensor to the continuous carbon monoxide stream under the rising concentration level of 2ppm, 5ppm, 10ppm and 20ppm.Sensor is at room temperature worked.This response is the function as the time, the resistance R under the resistance R under the situation that carbon monoxide exists and the situation that does not have carbon monoxide
0Normalized ratio record.The result confirms that sensor has responsive response to low-level gas.Response to CO is linear.
The demand to heating sensor has been eliminated in the further confirmation of above-mentioned these results, so that by utilizing grid bias to make sensor in room temperature (22 degrees centigrade) work down.
The inventor has been found that to work under the temperature of room temperature also be possible being lower than, for example-60 .Therefore, sensor can be worked under the atmospheric temperature that runs under the environment of 40,000 feet height of ground level arrival, and therefore is suitable for use in aircraft or other high altitude applications.Therefore, a kind of method of working sensor that makes can comprise according to temperature adjustment gate voltage.
The inventor further finds, can adjust gate voltage, so that be suitable for being in the different analyte gas in the broad concentration range.
Therefore, a kind of method of working sensor according to an embodiment of the invention that makes can comprise one of adjustment gate voltage and detection of compound or adjust the two in combination so that select analyte.
Although the present invention and advantage thereof are described in detail, should be appreciated that, can under the situation of the spirit and scope of the invention that does not depart from the claims qualification, make multiple variation alternative and modification to it.
Claims (according to the modification of the 19th of treaty)
1, a kind of sensor that is used for the existence of check and analysis thing gas, wherein said sensor by adjustment have characteristic of semiconductor the layer surface energy and regulate described have characteristic of semiconductor the layer conduction work, described sensor comprises:
Substrate;
Insulation course;
By described insulation course and described substrate separate have characteristic of semiconductor the layer;
First contact that contacts with described layer with characteristic of semiconductor;
Second contact that contacts with described layer with characteristic of semiconductor; With
The 3rd contact with described substrate contacts;
Wherein said layer with characteristic of semiconductor comprises and can produce chemically interactive compound with described analyte gas;
Wherein said the 3rd contact is the conducting stratum that is positioned on the described substrate, separates by insulator and described layer with characteristic of semiconductor; And
Wherein said insulation course, described layer, first contact, second contact and the 3rd contact with characteristic of semiconductor are disposed on the predetermined structure so that described sensor with the variable of described analyte gas level detect for when on described first contact and described the 3rd contact, applying voltage between described first contact and described second contact electric current present variable.
2, sensor according to claim 1, wherein said compound comprises metal oxide.
3, sensor according to claim 2, wherein said metal comprises transition metal.
4, sensor according to claim 3, wherein metal comprises the potpourri of metal.
5, sensor according to claim 3, wherein potpourri is binary, ternary, quaternary mixture, and the metal that wherein adds is as the adulterant that changes orbital energy level.
6, sensor according to claim 3, wherein said transition metal comprise 6B family element.
7, sensor according to claim 6, wherein said 6B family element comprises molybdenum oxide.
8, sensor according to claim 1, wherein said chemical interaction comprises electron transport.
9, sensor according to claim 8, wherein said electron transport comprise power supply that is carried out to described compound by described analyte gas.
10, sensor according to claim 8, wherein said electron transport comprises the electrophilic that described analyte gas is carried out from described compound.
11, sensor according to claim 1, wherein said analyte gas comprises carbon monoxide.
12, sensor according to claim 1, wherein said layer with characteristic of semiconductor comprises film.
13, sensor according to claim 12, wherein said film comprises a plurality of nano particles, described a plurality of nano particles comprise described compound.
14, sensor according to claim 13, wherein said nano particle is spherical.
15, sensor according to claim 13, wherein said nano particle right and wrong sphere.
16, sensor according to claim 2, wherein the continuous metal oxide has rough surface, and the pattern at described rough surface place limits crystal boundary.
17, sensor according to claim 1, wherein grid bias influence conduction by described layer with characteristic of semiconductor.
18, sensor according to claim 16, wherein grid bias influence the energy barrier between the crystal boundary.
19, sensor according to claim 13, wherein said nano particle has uniform size.
20, sensor according to claim 1, wherein said structure comprises thin-film transistor structure.
21, sensor according to claim 1 wherein utilizes to comprise that the method that makes nanoparticle growth makes described sensor, and described nano particle comprises described compound.22, sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor comprises electro-deposition.
23, sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor comprises sputter.
24, sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor directly occurs on the described insulation course or directly occurs on the conductive precursor of having of described insulation course.
25, sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor is left and non-directly generation mutually with the surface of insulated substrate or the precursor of described insulated substrate.
26, method according to claim 25, wherein said method further comprise described nano particle are applied on the described surface.
27, sensor according to claim 1 is wherein by comprising that depositing metal films, the method that described metallic film is transformed into its metal oxide subsequently make described sensor.
28, sensor according to claim 27 is wherein implemented described transformation to metal oxide by thermal annealing.
29, sensor according to claim 27 is wherein implemented described transformation to metal oxide by chemical reaction.
30, sensor according to claim 27 is wherein implemented described transformation to metal oxide by electrochemical reaction.
31, sensor according to claim 21, wherein said method further comprise described nano particle are carried out thermal annealing.
32, sensor according to claim 2, the wherein demand that does not have hot aspect of detection process.
33, sensor according to claim 2, the work of wherein said sensor is temperature independent, and is the function of gate voltage.
34, sensor according to claim 1, wherein said sensor can be worked under variable level of conductivity.
34, sensor according to claim 34, wherein said levels of current are lower than one (1) nanoampere.
36, a kind of utilization has the method for existence of the layer check and analysis thing gas of characteristic of semiconductor, wherein with the described layer of the mode modification that is selected from the group that comprises following mode: (a) adjust described surface energy, (b) and regulate described conduction and (c) its combination with layer of characteristic of semiconductor with layer of characteristic of semiconductor with characteristic of semiconductor.
37, method according to claim 36, wherein said analyte gas is CO.
38, method according to claim 36, wherein said layer with characteristic of semiconductor has surface topography.
39, according to the described method of claim 38, wherein said surface topography has formed crystal boundary.
40,, wherein there is energy barrier at described crystal boundary place according to the described method of claim 39.
41, according to the described method of claim 40, wherein said layer with characteristic of semiconductor is the part of sensor.
42, method according to claim 36 is wherein adjusted described layer with characteristic of semiconductor by means of applying bias voltage by the 3rd contact.
43, according to the described method of claim 40, wherein adjust described energy barrier by radiation.
44, according to the described method of claim 43, wherein said radiation is a light.
45, according to the described method of claim 40, wherein adjust described energy barrier by magnetic field.
46,, wherein adjust described energy barrier by changing described the material of formation with characteristic of semiconductor with layer of characteristic of semiconductor according to the described method of claim 40.
47, according to the described method of claim 41, wherein said layer with characteristic of semiconductor is different metal oxide.
48, according to the described method of claim 41, wherein said layer with characteristic of semiconductor is the potpourri of metal oxide.
49, method according to claim 36 is wherein by promoting electronics to adjust described surface energy from an energy band to another energy Tape movement.
50, according to the described method of claim 49, wherein said can band be molecular orbit.
51, method according to claim 36 is wherein adjusted described surface energy with layer of characteristic of semiconductor by means of applying grid bias by the 3rd contact.
52, according to the described method of claim 51, wherein said susceptibility depends on the adjustment to surface energy.
53, method according to claim 36 is wherein adjusted described surface energy with layer of characteristic of semiconductor by being exposed to radiation.
54, method according to claim 36 is wherein adjusted described surface energy with layer of characteristic of semiconductor by magnetic field.
55,, wherein adjust described energy barrier by changing described material with characteristic of semiconductor according to the described method of claim 40.
56, according to the described method of claim 55, wherein said material with characteristic of semiconductor is different metal oxide.
57, according to the described method of claim 55, wherein said material with characteristic of semiconductor is the potpourri of metal oxide.
58, method according to claim 36, wherein said layer with characteristic of semiconductor is a part that multiple analytes is had the sensor of susceptibility by control-grid bias.
59, according to the described method of claim 58, wherein said sensor has selectivity by applying specific grid bias to independent analyte.
60, a kind of gas sensor, described gas sensor comprises signal amplifier, described signal amplifier comprises thin film transistor (TFT), described thin film transistor (TFT) comprises the film with characteristic of semiconductor of molybdenum oxide, and wherein said gas sensor is by working with the described film with characteristic of semiconductor of the mode modification that is selected from the group that comprises following mode: (a) adjust described surface energy, (b) with film of characteristic of semiconductor and regulate described conduction and (c) its combination with film of characteristic of semiconductor.
61, a kind of method of sensing analyte gas, wherein said method has adopted the mode of utilizing the described sensor of claim 1.
Claims (64)
1. sensor that is used for the existence of check and analysis thing gas, wherein said sensor have by adjustment characteristic of semiconductor layer surface energy and regulate described conduction and work with layer of characteristic of semiconductor, described sensor comprises:
Substrate;
Insulation course;
By described insulation course and described substrate separate have characteristic of semiconductor the layer;
First contact that contacts with described layer with characteristic of semiconductor;
Second contact that contacts with described layer with characteristic of semiconductor; With
The 3rd contact with described substrate contacts;
Wherein said layer with characteristic of semiconductor comprises and can produce chemically interactive compound with described analyte gas;
Wherein said the 3rd contact is the conducting stratum that is positioned on the described substrate, separates by insulator and described layer with characteristic of semiconductor; And
Wherein said insulation course, described layer, first contact, second contact and the 3rd contact with characteristic of semiconductor are disposed on the predetermined structure so that described sensor with the variable of described analyte gas level detect for when on described first contact and described the 3rd contact, applying voltage between described first contact and described second contact electric current present variable.
2. sensor according to claim 1, wherein said compound comprises metal oxide.
3. sensor according to claim 2, wherein said metal comprises transition metal.
4. sensor according to claim 3, wherein metal comprises the potpourri of metal.
5. sensor according to claim 3, wherein potpourri is binary, ternary, quaternary mixture, and the metal that wherein adds is as the adulterant that changes orbital energy level.
6. sensor according to claim 3, wherein said transition metal comprise 6B family element.
7. sensor according to claim 6, wherein said 6B family element comprises molybdenum oxide.
8. sensor according to claim 1, wherein said chemical interaction comprises electron transport.
9. sensor according to claim 8, wherein said electron transport comprise power supply that is carried out to described compound by described analyte gas.
10. sensor according to claim 8, wherein said electron transport comprises the electrophilic that described analyte gas is carried out from described compound.
11. sensor according to claim 1, wherein said analyte gas comprises carbon monoxide.
12. sensor according to claim 1, wherein said layer with characteristic of semiconductor comprises film.
13. sensor according to claim 12, wherein said film comprises a plurality of nano particles, and described a plurality of nano particles comprise described compound.
14. sensor according to claim 13, wherein said nano particle is spherical.
15. sensor according to claim 13, wherein said nano particle right and wrong sphere.
16. sensor according to claim 2, wherein the continuous metal oxide has rough surface, and the pattern at described rough surface place limits crystal boundary.
17. sensor according to claim 1, wherein grid bias influence conduction by described layer with characteristic of semiconductor.
18. sensor according to claim 16, wherein grid bias influence the energy barrier between the crystal boundary.
19. sensor according to claim 13, wherein said nano particle has uniform size.
20. sensor according to claim 1, wherein said structure comprises thin-film transistor structure.
21. sensor according to claim 1 wherein utilizes to comprise that the method that makes nanoparticle growth makes described sensor, described nano particle comprises described compound.
22. sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor comprises electro-deposition.
23. sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor comprises sputter.
24. sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor directly occurs on the described insulation course or directly occurs on the conductive precursor of having of described insulation course.
25. sensor according to claim 12, wherein said growth with layer of characteristic of semiconductor is left and non-directly generation mutually with the surface of insulated substrate or the precursor of described insulated substrate.
26. method according to claim 25, wherein said method further comprise described nano particle is applied on the described surface.
27. sensor according to claim 1 is wherein by comprising that depositing metal films, the method that described metallic film is transformed into its metal oxide subsequently make described sensor.
28. sensor according to claim 27 is wherein implemented described transformation to metal oxide by thermal annealing.
29. sensor according to claim 27 is wherein implemented described transformation to metal oxide by chemical reaction.
30. sensor according to claim 27 is wherein implemented described transformation to metal oxide by electrochemical reaction.
31. sensor according to claim 21, wherein said method further comprise described nano particle is carried out thermal annealing.
32. gas sensor according to claim 1, wherein said gas sensor further comprises the microprocessor that is suitable for controlling described voltage.
33. gas sensor according to claim 1, wherein said gas sensor further comprises the radio frequency link that is suitable for the electric current variable is carried out remote reading.
34. gas sensor according to claim 1, wherein said gas sensor is suitable for use as quantimeter.
35. sensor according to claim 2, the wherein demand that does not have hot aspect of detection process.
36. sensor according to claim 2, the work of wherein said sensor is temperature independent, and is the function of gate voltage.
37. sensor according to claim 1, wherein said sensor can be worked under variable level of conductivity.
38. according to the described sensor of claim 37, wherein said levels of current is lower than one (1) nanoampere.
39. a utilization has the method for existence of the layer check and analysis thing gas of characteristic of semiconductor, wherein with the described layer with characteristic of semiconductor of the mode modification that is selected from the group that comprises following mode: (a) adjust described surface energy, (b) with layer of characteristic of semiconductor and regulate described conduction and (c) its combination with layer of characteristic of semiconductor.。
40. according to the described method of claim 39, wherein said analyte gas is CO.
41. according to the described method of claim 39, wherein said layer with characteristic of semiconductor has surface topography.
42. according to the described method of claim 41, wherein said surface topography has formed crystal boundary.
43., wherein have energy barrier at described crystal boundary place according to the described method of claim 42.
44. according to the described method of claim 43, wherein said layer with characteristic of semiconductor is the part of sensor.
45., wherein described layer with characteristic of semiconductor is adjusted by means of applying bias voltage by the 3rd contact according to the described method of claim 39.
46., wherein adjust described energy barrier by radiation according to the described method of claim 43.
47. according to the described method of claim 46, wherein said radiation is a light.
48., wherein adjust described energy barrier by magnetic field according to the described method of claim 43.
49., wherein adjust described energy barrier by changing described the material of formation with characteristic of semiconductor with layer of characteristic of semiconductor according to the described method of claim 43.
50. according to the described method of claim 44, wherein said layer with characteristic of semiconductor is different metal oxide.
51. according to the described method of claim 44, wherein said layer with characteristic of semiconductor is the potpourri of metal oxide.
52. according to the described method of claim 39, wherein by promoting electronics to adjust described surface energy to another energy Tape movement from an energy band.
53. according to the described method of claim 52, wherein said can band be molecular orbit.
54., wherein described surface energy with layer of characteristic of semiconductor is adjusted by means of applying grid bias by the 3rd contact according to the described method of claim 39.
55. according to the described method of claim 54, wherein said susceptibility depends on the adjustment to surface energy.
56., wherein described surface energy with layer of characteristic of semiconductor is adjusted by being exposed to radiation according to the described method of claim 39.
57., wherein described surface energy with layer of characteristic of semiconductor is adjusted by magnetic field according to the described method of claim 39.
58., wherein adjust described energy barrier by changing described material with characteristic of semiconductor according to the described method of claim 43.
59. according to the described method of claim 58, wherein said material with characteristic of semiconductor is different metal oxide.
60. according to the described method of claim 58, wherein said material with characteristic of semiconductor is the potpourri of metal oxide.
61. according to the described method of claim 39, wherein said layer with characteristic of semiconductor is a part that multiple analytes is had the sensor of susceptibility by control-grid bias.
62. according to the described method of claim 61, wherein said sensor has selectivity by applying specific grid bias to independent analyte.
63. gas sensor, described gas sensor comprises signal amplifier, described signal amplifier comprises thin film transistor (TFT), described thin film transistor (TFT) comprises the film with characteristic of semiconductor of molybdenum oxide, and wherein said gas sensor is by working with the described film with characteristic of semiconductor of the mode modification that is selected from the group that comprises following mode: (a) adjust described surface energy, (b) with film of characteristic of semiconductor and regulate described conduction and (c) its combination with film of characteristic of semiconductor.
64. the method for a sensing analyte gas, wherein said method has adopted the mode of utilizing the described sensor of claim 1.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66328605P | 2005-03-18 | 2005-03-18 | |
| US60/663,286 | 2005-03-18 | ||
| US11/375,791 | 2006-03-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101142476A true CN101142476A (en) | 2008-03-12 |
Family
ID=39193590
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA200680008191XA Pending CN101142476A (en) | 2005-03-18 | 2006-03-17 | Gated gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101142476A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103500798A (en) * | 2013-09-04 | 2014-01-08 | 中国科学院苏州纳米技术与纳米仿生研究所 | Gas sensor based on field effect transistor structure and preparation method thereof |
| CN103575775B (en) * | 2012-07-31 | 2018-08-17 | 罗伯特·博世有限公司 | The method and control device of gas parameter are measured by means of gas sensing fet |
| CN108447915A (en) * | 2018-03-02 | 2018-08-24 | 华中科技大学 | A kind of thin film field effect transistor type gas sensor and preparation method thereof |
| CN114720519A (en) * | 2021-01-06 | 2022-07-08 | 长城汽车股份有限公司 | Carbon monoxide sensor, carbon monoxide monitoring system and vehicle |
-
2006
- 2006-03-17 CN CNA200680008191XA patent/CN101142476A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103575775B (en) * | 2012-07-31 | 2018-08-17 | 罗伯特·博世有限公司 | The method and control device of gas parameter are measured by means of gas sensing fet |
| CN103500798A (en) * | 2013-09-04 | 2014-01-08 | 中国科学院苏州纳米技术与纳米仿生研究所 | Gas sensor based on field effect transistor structure and preparation method thereof |
| CN103500798B (en) * | 2013-09-04 | 2016-08-17 | 中国科学院苏州纳米技术与纳米仿生研究所 | Gas sensor based on field-effect transistor structure and preparation method thereof |
| CN108447915A (en) * | 2018-03-02 | 2018-08-24 | 华中科技大学 | A kind of thin film field effect transistor type gas sensor and preparation method thereof |
| CN114720519A (en) * | 2021-01-06 | 2022-07-08 | 长城汽车股份有限公司 | Carbon monoxide sensor, carbon monoxide monitoring system and vehicle |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kaur et al. | One-dimensional nanostructured oxide chemoresistive sensors | |
| US7950271B2 (en) | Gated beta-molybdenum oxide sensor | |
| EP1864122A2 (en) | Gated gas sensor | |
| Wöllenstein et al. | Cobalt oxide based gas sensors on silicon substrate for operation at low temperatures | |
| Ahmad et al. | Fabrication of a non-enzymatic glucose sensor field-effect transistor based on vertically-oriented ZnO nanorods modified with Fe2O3 | |
| US7522040B2 (en) | Remotely communicating, battery-powered nanostructure sensor devices | |
| Liu | Towards development of chemosensors and biosensors with metal-oxide-based nanowires or nanotubes | |
| Wöllenstein et al. | Material properties and the influence of metallic catalysts at the surface of highly dense SnO2 films | |
| US20060263255A1 (en) | Nanoelectronic sensor system and hydrogen-sensitive functionalization | |
| Batra et al. | Micro-and nano-structured metal oxides based chemical sensors: an overview | |
| Lee et al. | Ultra-low-power e-nose system based on multi-micro-led-integrated, nanostructured gas sensors and deep learning | |
| CN102313765A (en) | Biosensor base on zinc oxide and high electron mobility transistor and its preparation method | |
| Zhang et al. | Low-concentration NO x gas analysis using single bimodular ZnO nanorod sensor | |
| Bastatas et al. | Emergent electrical properties of ensembles of 1D nanostructures and their impact on room temperature electrical sensing of ammonium nitrate vapor | |
| CN101142476A (en) | Gated gas sensor | |
| Desai et al. | Indium sesquitelluride (In2Te3) thin film gas sensor for detection of carbon dioxide | |
| Kondratev et al. | Silicon nanowire-based room-temperature multi-environment ammonia detection | |
| RU2718133C1 (en) | Gas-sensitive detector | |
| Oprea et al. | Copper phthalocyanine suspended gate field effect transistors for NO2 detection | |
| Bhattacharyya et al. | Resistive and capacitive measurement of nano-structured gas sensors | |
| JP4696723B2 (en) | Biosensor | |
| Kim et al. | Solution-gated nitrate sensitive field effect transistor with hybrid film: CVD graphene/polymer selective membrane | |
| US20070013013A1 (en) | Semiconductor chemical sensor | |
| Nien et al. | Study of the nonenzymatic CZO lactic acid sensor modified by graphitic carbon nitride and iron–platinum nanoparticles | |
| US20190317036A1 (en) | Gas sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20080312 |