CN109856198B

CN109856198B - Continuous response hydrogen array gas-sensitive sensor and preparation method thereof

Info

Publication number: CN109856198B
Application number: CN201910022568.6A
Authority: CN
Inventors: 高炬
Original assignee: Zaozhuang University
Current assignee: Zaozhuang University
Priority date: 2019-01-10
Filing date: 2019-01-10
Publication date: 2021-09-24
Anticipated expiration: 2039-01-10
Also published as: CN109856198A

Abstract

The invention belongs to the technical field of hydrogen sensors, and particularly relates to a continuous response hydrogen array gas-sensitive sensor and a preparation method thereof. The continuous response hydrogen array gas sensor comprises a substrate and a Pd material nano seam electrode layer arranged on the substrate, wherein the Pd material nano seam electrode layer comprises a plurality of strip-shaped Pd material strips and electrodes plated on the outermost Pd material strips, which are sequentially arranged, and the width of a gap between every two adjacent Pd material strips is continuously changed from one end to the other end. The minimum hydrogen detection concentration in the technical scheme provided by the invention is determined by the minimum distance of the wedge-shaped gap, the slope of the wedge-shaped gap controls the speed of reducing the resistance value of the sensor, namely the response sensitivity, and the strength of the detection signal can be adjusted through the number of the array stripes.

Description

Continuous response hydrogen array gas-sensitive sensor and preparation method thereof

Technical Field

The invention belongs to the technical field of hydrogen sensors, and particularly relates to a continuous response hydrogen array gas-sensitive sensor and a preparation method thereof.

Background

The hydrogen sensor can be classified into an optical type and an electrical characteristic type. The optical hydrogen sensor detects hydrogen by using the change of optical characteristics of a hydrogenated material film after hydrogen absorption. The sensor has the advantages of high safety and high sensitivity, and has the disadvantages of complex test system, slow response, difficult operation and control and short service life. The detection principle of the electrical characteristic type hydrogen sensor is to express the catalytic reaction state of hydrogen on an electrode in the form of an electrical signal so as to obtain the volume fraction of the hydrogen. The electrical characteristic type hydrogen sensor is simple to operate, easy to miniaturize and integrate, and can be used for a long time without maintenance.

The traditional electric characteristic detection mode has the defects of small response signal, low sensitivity, poor anti-interference capability and the like. Therefore, many researches on improving the signal strength and the anti-interference capability of the electrical characteristic type hydrogen sensor are carried out. The hydrogen-sensitive electrode mainly comprises chemical components and combination performance of a hydrogen-sensitive material, alloy and structural characteristics of the hydrogen-sensitive material and the like, for example, a plurality of groups of Pd material electrodes are disclosed in Chinese patent CN102313761A to form a plurality of different plane electrode intervals, the interval width value accords with an arithmetic progression, each electrode with the same width comprises a plurality of parallel electrode groups to form a group of hydrogen detection loops. The sensitivity of the sensor is improved by using the small-scale nano-slits, the measurement range of the sensor is improved by using the large-scale nano-slits, but the scheme cannot realize the continuous response of the hydrogen material, and the electrode arrangement mode of parallel arrangement with the same size and equal-difference array arrangement with different electrode distances increases the manufacturing difficulty and improves the cost.

Disclosure of Invention

The invention provides a continuous response hydrogen array gas sensor and a preparation method thereof, which are used for solving the problems of sensitivity, measuring range, continuity, practicability and the like of the existing hydrogen sensor.

In order to solve the technical problems, the technical scheme of the invention is as follows: the continuous response hydrogen array gas sensor comprises a substrate and a Pd material nano seam electrode layer arranged on the substrate, wherein the Pd material nano seam electrode layer comprises a plurality of strip-shaped Pd material strips and electrodes plated on the outermost Pd material strips, which are sequentially arranged, and the width of a gap between every two adjacent Pd material strips is continuously changed from one end to the other end.

Optionally, the width of the gap between the adjacent Pd material strips varies linearly from wide to narrow from one end to the other end.

In the hydrogen-free environment, because Pd is a low-resistance metal phase, the Pd materials are spaced and do not contact with each other, the whole sensor is not conducted, and the two electrodes are in an insulated state. When the sensor is exposed to hydrogen environment, Pd meets hydrogen to form Pd-based hydride PdH_xBecause of HILE effect, Pd-based hydride film expands to connect Pd materials with space to form a micro-mechanical switch with micron size, two electrodes are conducted to detect hydrogen, and the space between Pd-based hydride film expands more with the increase of hydrogen concentration due to the gradual widening of the space, so that the space can be filled upThe wider the distance, so that the contact between the Pd materials gradually increases, the resistance between the two electrodes also decreases linearly, and a linear response is obtained in which the resistance value decreases as the hydrogen concentration increases. Compared with the prior art, the effect of parallel connection enhancement can be realized only by arranging one group of electrodes.

Optionally, the substrate comprises a silicon substrate and a silicon dioxide film layer plated on the silicon substrate, the silicon substrate forms silicon-based micro-nano stripes by using a photoetching technology, the silicon-based micro-nano stripes correspond to the Pd material strips one by one, and the Pd material strips cover the silicon dioxide film layer.

Optionally, the thickness of the silicon substrate is larger than 200 micrometers, the silicon-based micro-nano stripes are formed by adopting a photoetching technology, and the etching depth of the silicon-based micro-nano stripe layer is 50-100 micrometers.

Optionally, the thickness of the silicon dioxide film layer is 100-1000 nanometers.

Optionally, the Pd material strips are wedge-shaped, and all Pd material strips have the widest end on one side and the narrowest end on the other side.

Optionally, the Pd material strips are the same size, and the gaps between adjacent Pd material strips are wedge-shaped.

Optionally, the narrowest part of the gap is 0-10 nm, and the widest part of the gap is 10-1000 nm.

Optionally, the strip of Pd material is the same size as the slit.

The invention also provides a preparation method of the continuous response hydrogen arrayed gas sensor, which comprises the following steps: firstly, a Pd material coating is deposited on a substrate, then Pd material strips arranged in an array are prepared by adopting an ultraviolet photoetching technology, and finally, metal electrodes are plated on the outermost Pd material strips.

Optionally, the substrate is a silicon substrate on which a silicon dioxide film is plated as a substrate.

The minimum hydrogen detection concentration in the technical scheme provided by the invention is determined by the minimum distance of the wedge-shaped gap, the slope of the wedge-shaped gap controls the speed of reducing the resistance value of the sensor, namely the response sensitivity, and the strength of the detection signal can be adjusted through the number of the array stripes.

Drawings

FIG. 1 is a schematic diagram of the structure of one embodiment of a continuous response hydrogen-based gas sensor array according to the present invention;

fig. 2 is a top view of fig. 1.

Shown in the figure:

the device comprises a 10-silicon substrate, 11-silicon substrate micro-nano stripes, a 20-silicon dioxide film layer, a 30-Pd material nano seam electrode layer, a 31-Pd material strip, a 32-electrode and a 40-seam.

Detailed Description

For ease of understanding, the continuous response hydrogen gas array gas sensor is described below in connection with examples, which are intended to be illustrative only and are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations and positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixed or detachably or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, in the continuous response hydrogen array gas sensor, a silicon substrate 10 is plated with a silicon dioxide film layer 20 with a thickness of 800 nm, then a Pd material coating is deposited on the silicon dioxide film layer 20, and a wedge gap 40 is photoetched by using an ultraviolet lithography technique, so that silicon-based micro-nano stripes 11 with an etching depth of 100 microns are formed on the silicon substrate 10, a Pd material nano-gap electrode layer 30 is formed on the silicon dioxide film layer 20, and the total thickness of the silicon substrate 10 reaches 200 microns.

As shown in fig. 2, the Pd material nanoslit electrode layer 30 includes a plurality of strip-shaped Pd material strips 31 arranged from left to right, and electrodes 32 plated on the leftmost and rightmost Pd material strips 31.

As shown in fig. 1 and 2, the silicon-based micro-nano stripes 11 correspond to the Pd material strips 31 one-to-one, and based on the processing process, the Pd material strips 31 have the same cross section as the corresponding silicon-based micro-nano stripes 11 and are all wedge-shaped.

As shown in fig. 2, the Pd material strips 31 have the same size, the widest end is located at the upper side, the narrowest end is located at the lower side, so as to facilitate alignment and processing, and the gaps 40 between adjacent Pd material strips 31 are formed to have a shape complementary to that of the Pd material strips 31 and also have a wedge shape, and preferably, the Pd material strips 31 have the same size as the wedge-shaped gaps 40.

The narrowest part of the wedge-shaped gap 40 is 2 nanometers, and the widest part is 1000 nanometers. Experiments prove that stable change data can be detected when the hydrogen concentration detection range is 1-40000 ppm, the detected resistance value change should be in continuous response along with the reduction of the wedge-shaped gap, and the hydrogen concentration can be accurately calculated according to the resistance value.

It should be noted that the present embodiment only provides a description of the structure of one row of Pd material strips 31, and the Pd material strips can be arranged in multiple rows and multiple columns as required, and the structure of the slits 40 is not limited to be wedge-shaped, and other linear changes extended from the present concept are all included in the scope of the present invention.

In addition, the thickness of the silicon dioxide film layer 20 can be 100-1000 nm, the etching depth of the silicon-based micro-nano stripe 11 can be 50-100 microns, the total thickness of the silicon substrate 10 needs to be more than 200 microns, the narrowest part of the gap can be designed to be 0-10 nm, and the widest part can be designed to be 10-1000 nm.

Finally, it should be noted that: the above examples are only for illustrating the technical solutions of the present invention, and are not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or some or all of the technical features may be equivalently replaced, and such modifications or replacements may not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous response hydrogen gas array gas sensor is characterized by comprising a substrate and a Pd material nano seam electrode layer arranged on the substrate, wherein the Pd material nano seam electrode layer comprises a plurality of strip-shaped Pd material strips and electrodes plated on the outermost Pd material strips, which are sequentially arranged, and the width of a gap between every two adjacent Pd material strips is continuously changed from one end to the other end.

2. The continuously responsive hydrogen-based gas-sensitive array sensor according to claim 1, wherein the width of the gap between adjacent strips of Pd material varies linearly from one end to the other end from wide to narrow.

3. The continuous-response hydrogen-array gas-sensitive sensor according to claim 1, wherein the substrate comprises a silicon substrate and a silicon dioxide film layer plated on the silicon substrate, the silicon substrate is formed with silicon-based micro-nano stripes by a photolithography technique, the silicon-based micro-nano stripes correspond to the Pd material strips in a one-to-one correspondence, and the Pd material strips cover the silicon dioxide film layer.

4. The continuous-response hydrogen-gas-array gas-sensitive sensor according to claim 3, wherein the thickness of the silicon substrate is greater than 200 microns, the silicon-based micro-nano stripes are formed by a photoetching technology, and the etching depth of the silicon-based micro-nano stripe layer is 50-100 microns.

5. The continuous-response hydrogen-arrayed gas-sensitive sensor according to claim 3, wherein the thickness of the silicon dioxide film layer is 100 to 1000 nm.

6. The continuously responsive hydrogen-based gas sensor array according to claim 2, wherein the strips of Pd material are wedge-shaped, and all strips of Pd material have their widest end on one side and their narrowest end on the other side.

7. The continuously responsive hydrogen arrayed gas sensitive sensor according to claim 6, wherein the strips of Pd material are of the same size, and the gaps between adjacent strips of Pd material are wedge-shaped.

8. The continuous-response hydrogen-gas-arrayed gas-sensitive sensor according to claim 7, wherein the narrowest point of the slit is 0 to 10 nm, and the widest point is 10 to 1000 nm.

9. A method for preparing a continuous response hydrogen arrayed gas sensor as claimed in any one of claims 1 to 8, comprising the steps of: firstly, a Pd material coating is deposited on a substrate, then Pd material strips arranged in an array are prepared by adopting an ultraviolet photoetching technology, and finally, metal electrodes are plated on the outermost Pd material strips.

10. The method for preparing a continuous response hydrogen arrayed gas sensor of claim 9, wherein the substrate is a silicon substrate coated with a silicon dioxide film as a substrate.