Thin film device with bias field exchange and photoelectric detection performance and preparation method thereof

Abstract

The invention relates to the technical field of magnetic photoelectric detection, in particular to a thin film device with bias field exchange and photoelectric detection performance and a preparation method thereof, and the thin film device comprises a substrate layer, an antiferromagnetic semiconductor layer, a ferromagnetic semiconductor layer and an electrode layer which are sequentially stacked from bottom to top; materials of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer have a photoelectric effect. The thin film device not only has good photoelectric detection performance, but also has a strong exchange bias field; the exchange bias phenomenon comes from a double-layer film structure of an antiferromagnetic semiconductor layer and a ferromagnetic semiconductor layer, the magnetic moment of the ferromagnetic semiconductor layer is directly coupled with the magnetic moment which is not counteracted at the magnetic moment interface of the antiferromagnetic semiconductor layer, so that the ferromagnetic semiconductor layer is pinned, and the exchange bias phenomenon is formed; when the ferromagnetic semiconductor layer and the antiferromagnetic semiconductor layer are made of materials with photoelectric effects, the thin film not only has an exchange bias field, but also has certain photoelectric detection capability.

Description

Technical Field

[0001] The invention relates to the field of magnetic photoelectric detection technology, and in particular to a thin film device with exchange bias field and photoelectric detection performance and a preparation method thereof. Background Art

[0002] The exchange bias effect is an interface effect produced when the ferromagnetic layer and the antiferromagnetic layer in a magnetic material come into contact. This effect is an important property of magnetic spin materials and has great prospects in applications. It is one of the important performance indicators of future magnetic random access memory, fast storage and magnetic superconducting devices. Since there are many known systems that can be used to produce exchange bias, and there are also many kinds of ferromagnetic materials and antiferromagnetic materials, there are also many research and experimental methods on exchange bias. At the same time, with the development of science and technology, the performance of photodetectors has been continuously improved, and it has also shown important application value in optical communications, thermal imaging, medical treatment, military and other fields.

[0003] With the development of self-learning electronic detection, detection devices with optical-electrical-magnetic coupling, that is, detectors with strong magnetic-exchange bias field and high photodetection performance are increasingly needed. Magnetron sputtering is a very common method for preparing thin films. Generally speaking, thin films prepared by magnetron sputtering either have only good exchange bias field but weak photodetection performance, or only have good photodetection performance but no exchange bias field.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a thin film device with exchange bias field and photoelectric detection performance and a preparation method thereof, aiming to solve the problem that existing thin film devices cannot simultaneously achieve good exchange bias field and photoelectric detection performance.

[0006] The technical solution of the present invention is as follows:

[0007] A thin film device with exchange bias field and photoelectric detection performance comprises a substrate layer, an antiferromagnetic semiconductor layer, a ferromagnetic semiconductor layer and an electrode layer which are stacked in sequence from bottom to top; the materials of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer have a photoelectric effect.

[0008] The thin film device with exchange bias field and photoelectric detection performance, wherein the material of the antiferromagnetic semiconductor layer includes one or more of cobalt oxide, nickel oxide, and manganese oxide.

[0009] The thin film device with exchange bias field and photoelectric detection performance, wherein the ferromagnetic semiconductor layer is a ferromagnetic material with a spinel structure; the ferromagnetic material includes one or more of cobalt ferrite, nickel ferrite, and chromium dioxide.

[0010] The thin film device with exchange bias field and photoelectric detection performance, wherein the material of the electrode layer includes an alloy formed by one or more of gold, platinum, silver, tantalum, palladium, titanium, copper, chromium, and molybdenum; and / or the substrate layer is a glass substrate with grid-shaped stripes of indium tin oxide, a glass substrate with fully conductive indium tin oxide, an indium tin oxide flexible substrate, a silicon dioxide substrate with a gold electrode, and an aluminum oxide substrate with a prefabricated electrode; the electrode layer is connected to the conductive layer on the substrate layer.

[0011] In the thin film device having exchange bias field and photoelectric detection performance, the ferromagnetic semiconductor layer can be replaced by a ferromagnetic metal layer or a ferromagnetic conductor layer.

[0012] The thin film device with exchange bias field and photoelectric detection performance, wherein the thickness of the antiferromagnetic semiconductor layer is between 5-200nm; and / or the thickness of the ferromagnetic semiconductor layer is between 5-200nm.

[0013] The thin film device with exchange bias field and photoelectric detection performance, wherein the thickness of the electrode layer is 5-80nm; the thickness of the substrate layer is 0.5-2mm.

[0014] A method for preparing a thin film device having an exchange bias field and photoelectric detection performance comprises the steps of:

[0015] Providing a substrate, a ferromagnetic semiconductor material target, an antiferromagnetic semiconductor material target, and an electrode material target, and partially covering the substrate;

[0016] Sputtering the antiferromagnetic semiconductor material target onto the substrate to obtain an antiferromagnetic semiconductor layer;

[0017] Sputtering the ferromagnetic semiconductor material target onto the antiferromagnetic semiconductor layer to obtain a ferromagnetic semiconductor layer;

[0018] removing the masked portion on the substrate, and sputtering the electrode material target onto the ferromagnetic semiconductor layer and the substrate to obtain a thin film device precursor;

[0019] The thin film device precursor is annealed to obtain a thin film device.

[0020] The method for preparing a thin film device with an exchange bias field and photoelectric detection performance, wherein the sputtering power of sputtering the antiferromagnetic semiconductor material target onto the substrate is 75-120W, and the sputtering time is 1-15 minutes; the sputtering power of sputtering the ferromagnetic semiconductor material target onto the antiferromagnetic semiconductor layer is 50-80W, and the sputtering time is 30-90 minutes; the sputtering power of sputtering the electrode material target onto the ferromagnetic semiconductor layer and the substrate is 90-110W, and the sputtering time is 30-120 seconds.

[0021] The method for preparing the thin film device with exchange bias field and photoelectric detection performance, wherein the temperature of the annealing treatment is 200-800° C., and the time of the annealing treatment is 0.5-8 hours.

[0022] Beneficial effects: The present invention provides a thin film device with an exchange bias field and photoelectric detection performance and a preparation method thereof. The thin film device with an exchange bias field and photoelectric detection performance includes a substrate layer, an antiferromagnetic semiconductor layer, a ferromagnetic semiconductor layer, and an electrode layer stacked in sequence from bottom to top; the materials of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer have a photoelectric effect. The thin film device of the present invention not only has good photoelectric detection performance, but also has a strong exchange bias field; the exchange bias phenomenon originates from the double-layer film structure of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer, the magnetic moment of the ferromagnetic semiconductor layer is directly coupled with the uncancelled magnetic moment at the interface of the magnetic moment of the antiferromagnetic semiconductor layer, so that the ferromagnetic semiconductor layer is pinned, thereby forming an exchange bias phenomenon; and the photoelectric effect is a phenomenon that when a photon hits the surface of a material, it transfers energy to the electrons of the material, causing electrons to be emitted from atoms or molecules, and when electron holes are formed, the generation of these carriers causes current to flow, thereby generating an electrical signal proportional to the intensity of the incident light; when the ferromagnetic semiconductor layer and the antiferromagnetic semiconductor layer are prepared from materials with a photoelectric effect, the film not only has an exchange bias field, but also has a certain photoelectric detection capability. Specifically, the role of the substrate layer is to carry the device, and the conductive layer and the electrode layer on the substrate layer are simultaneously used as wires at both ends of the vertical film, so that the double-layer film becomes a photodiode, which has the conditions for photoelectric detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of a thin film device having exchange bias field and photoelectric detection performance;

[0024] Figure 2 Schematic diagram of an indium tin oxide glass substrate with nine grating stripes in Example 1, with necessary parts covered by PEN tape;

[0025] Figure 3 To use Figure 2Schematic diagram of a sample with a ferromagnetic semiconductor layer and an antiferromagnetic semiconductor layer as a heterojunction prepared on the substrate shown;

[0026] Figure 4 For Figure 3 Schematic diagram of preparing gold electrodes based on the present invention;

[0027] Figure 5 The light response curve diagram of the thin film device prepared in Example 1 obtained by testing on a 4200 photoelectric probe station;

[0028] Figure 6 The magnetic field magnitude vs. sample magnetization intensity curve obtained by testing the thin film device prepared in Example 1 in a comprehensive physical property measurement system;

[0029] Description of reference numerals: substrate layer 10 , conductive layer 11 , antiferromagnetic semiconductor layer 20 , ferromagnetic semiconductor layer 30 , electrode layer 40 . DETAILED DESCRIPTION

[0030] The present invention provides a thin film device with exchange bias field and photoelectric detection performance and a preparation method thereof. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0032] like Figure 1 As shown, the present invention provides a thin film device with exchange bias field and photoelectric detection performance, including a substrate layer 10, an antiferromagnetic semiconductor layer 20, a ferromagnetic semiconductor layer 30, and an electrode layer 40 stacked in sequence from bottom to top; the materials of the antiferromagnetic semiconductor layer 20 and the ferromagnetic semiconductor layer 30 have a photoelectric effect.

[0033] In this embodiment, the thin film device not only has good photoelectric detection performance, but also has a strong exchange bias field; the exchange bias phenomenon originates from the double-layer film structure of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer, the magnetic moment of the ferromagnetic semiconductor layer is directly coupled with the uncancelled magnetic moment at the interface of the magnetic moment of the antiferromagnetic semiconductor layer, so that the ferromagnetic semiconductor layer is pinned, thereby forming an exchange bias phenomenon; when the temperature is above the Neel temperature of the antiferromagnetic semiconductor layer and below the Curie temperature of the ferromagnetic semiconductor layer, and an external magnetic field is applied, the magnetic moment of the ferromagnetic semiconductor layer in the double-layer film structure moves along the direction of the external magnetic field. Orderly arrangement; During the process of field cooling, the magnetic moment of the antiferromagnetic semiconductor layer changes from random arrangement to ordered arrangement, and the arrangement of the magnetic moment close to the ferromagnetic semiconductor layer tends to be consistent with the magnetic moment of the ferromagnetic semiconductor layer, which is the direction of the exchange bias field; the antiferromagnetic magnetic moment is difficult to be affected by the outside world, so when the magnetic moment of the ferromagnetic semiconductor layer is reversed by the change of the external magnetic field, it is necessary to overcome the energy generated by the coupling with the interface of the antiferromagnetic semiconductor layer. This energy is equivalent to an additional superposition of a magnetic field, which is the exchange bias field Heb, which originates from the uncompensated irreversible interface spin in the interface of the antiferromagnetic semiconductor layer. The photoelectric effect is a phenomenon that when photons hit the surface of a material, they transfer energy to the electrons of the material, causing electrons to be emitted from atoms or molecules and forming electron holes. The generation of these carriers causes current to flow, thereby generating an electrical signal proportional to the intensity of the incident light; when the ferromagnetic semiconductor layer and the antiferromagnetic semiconductor layer are made of materials with photoelectric effect, the film not only has an exchange bias field, but also has a certain photoelectric detection capability. Specifically, the function of the substrate layer is to carry the device, and the conductive layer and electrode layer on the substrate layer also serve as wires at both ends of the vertical film, turning the double-layer film into a photodiode with the conditions for photoelectric detection.

[0034] Specifically, the thin film device provided by the present invention has both good photoelectric detection performance and a strong exchange bias field. According to characterization, the photoelectric detection performance of the thin film device is: responsivity R = 1.31*10 -7 (A / W); the exchange bias field is Heb=12693.75(Oe). And its photoelectric detection performance is repeatable, and the performance value tested under the same conditions does not change significantly after 100 tests; at the same time, its magnetic properties fluctuate by only about 10% under 10 training effect tests, indicating that the thin film device of the present invention has both good photoelectric detection performance and stability, as well as a strong exchange bias field.

[0035] In some embodiments, the antiferromagnetic semiconductor layer 20 and the ferromagnetic semiconductor layer 30 have the same area and are smaller than the conductive layer 11 on the substrate layer 10, so that part of the conductive layer 11 on the substrate layer 10 is exposed; the electrode layer 40 is connected to the exposed part of the conductive layer 11.

[0036] In some embodiments, the material of the antiferromagnetic semiconductor layer includes one or more of cobalt oxide, nickel oxide, and manganese oxide. The antiferromagnetic semiconductor layer is an antiferromagnetic material used to pin the magnetic moment of the ferromagnetic layer. The antiferromagnetic semiconductor layer is prepared by using one or more of cobalt oxide, nickel oxide, and manganese oxide, which can bring photoelectric detection capabilities to the thin film device and enhance the photoelectric response of the device.

[0037] In some embodiments, the ferromagnetic semiconductor layer is a ferromagnetic material with a spinel structure; the ferromagnetic material includes one or more of cobalt ferrite, nickel ferrite, and chromium dioxide. The above materials have good photoelectric response, and this type of material is the core of the double-layer film device of the present invention, providing strong ferromagnetism and photoelectric detection capabilities.

[0038] In some embodiments, the material of the electrode layer includes an alloy formed by one or more of gold, platinum, silver, tantalum, palladium, titanium, copper, chromium, and molybdenum; and / or the substrate layer is a glass substrate with grid-shaped stripes of indium tin oxide, a glass substrate with full-conductive indium tin oxide, an indium tin oxide flexible substrate, a silicon dioxide substrate with gold electrodes, and an aluminum oxide substrate with prefabricated electrodes; the electrode layer is connected to the conductive layer on the substrate layer. The above substrate can provide a conductive layer for a thin film device and carry a double-layer thin film material to form a device.

[0039] Specifically, the electrode layer is made of a precious metal that is not easily oxidized and is in the shape of a grid-like stripe. Precious metals that are not easily oxidized are generally gold, in addition to platinum, silver, tantalum, palladium, etc. and their alloys; sometimes, some light metals with excellent performance are used together, such as titanium, copper, chromium, molybdenum, etc. and their alloys; the purpose of selecting such materials is to prepare electrodes with low resistance and conductivity, reduce the impact of noise and resistance on photoelectric detection performance, and greatly extend the life of the device.

[0040] In some embodiments, the electrode layer may be in a ring shape but is not limited to it, and may also be a noble metal conductive wire.

[0041] In some embodiments, the ferromagnetic semiconductor layer can be replaced by a ferromagnetic metal layer or a ferromagnetic conductor layer, such as a rare earth-cobalt system, an iron-chromium-cobalt system, a neodymium-iron-boron system, an iron-cobalt alloy, etc. The thin film device obtained by replacing the ferromagnetic semiconductor layer with a ferromagnetic metal layer or a ferromagnetic conductor layer has good photoelectric detection performance and a strong exchange bias field.

[0042] In some embodiments, the thickness of the antiferromagnetic semiconductor layer is between 5-200 nm; and / or, the thickness of the ferromagnetic semiconductor layer is between 5-200 nm. The ferromagnetic semiconductor layer is the core material of the thin film device and the source of the magnetic and photoelectric detection capabilities of the device, and requires a certain thickness; the antiferromagnetic semiconductor layer mainly functions to pin the magnetic moment of the ferromagnetic semiconductor layer, so the thickness is slightly thinner.

[0043] In a preferred embodiment, the thickness of the ferromagnetic semiconductor layer is greater than the thickness of the antiferromagnetic semiconductor layer.

[0044] In some embodiments, the thickness of the electrode layer is 5-80 nm; the thickness of the substrate layer is 0.5-2 mm. The thickness of the substrate is a glass substrate visible to the naked eye; the thickness of the electrode layer only needs to meet the conductivity requirements and does not need to be prepared too thick; controlling the thickness of the substrate layer within the above range can play the role of supporting thin film devices.

[0045] In addition, the present invention also provides a method for preparing a thin film device having an exchange bias field and photoelectric detection performance, comprising the steps of:

[0046] Step S10: providing a substrate, a ferromagnetic semiconductor material target, an antiferromagnetic semiconductor material target, and an electrode material target, and partially masking the substrate;

[0047] Step S20: sputtering the antiferromagnetic semiconductor material target onto the substrate to obtain an antiferromagnetic semiconductor layer;

[0048] Step S30: sputtering the ferromagnetic semiconductor material target onto the antiferromagnetic semiconductor layer to obtain a ferromagnetic semiconductor layer;

[0049] Step S40: removing the masked portion on the substrate, and sputtering the electrode material target onto the ferromagnetic semiconductor layer and the substrate to obtain a thin film device precursor;

[0050] Step S50: performing annealing treatment on the thin film device precursor to obtain a thin film device.

[0051] In this embodiment, the thin film device prepared by the above preparation method not only has good photoelectric detection performance, but also has a strong exchange bias field; the exchange bias phenomenon comes from the double-layer film structure of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer, the magnetic moment of the ferromagnetic semiconductor layer is directly coupled with the uncancelled magnetic moment at the interface of the magnetic moment of the antiferromagnetic semiconductor layer, so that the ferromagnetic semiconductor layer is pinned, thereby forming an exchange bias phenomenon; and the photoelectric effect is a phenomenon that when a photon hits the surface of a material, it transfers energy to the electrons of the material, causing electrons to be emitted from atoms or molecules, and when electron holes are formed, the generation of these carriers causes current to flow, thereby generating an electrical signal proportional to the intensity of the incident light; when the ferromagnetic semiconductor layer and the antiferromagnetic semiconductor layer are prepared from materials with a photoelectric effect, the film not only has an exchange bias field, but also has a certain photoelectric detection capability. Specifically, the role of the substrate layer is to carry the device, and the conductive layer and the electrode layer on the substrate layer are simultaneously used as wires at both ends of the vertical film, so that the double-layer film becomes a photodiode, which has the conditions for photoelectric detection.

[0052] In some embodiments, the sputtering power of the antiferromagnetic semiconductor material target material sputtering onto the substrate is 75-120W, and the sputtering time is 1-15 minutes; the sputtering power of the ferromagnetic semiconductor material target material sputtering onto the antiferromagnetic semiconductor layer is 50-80W, and the sputtering time is 30-90 minutes; the sputtering power of the electrode material target material sputtering onto the ferromagnetic semiconductor layer and the substrate is 90-110W, and the sputtering time is 30-120 seconds. Different sputtering powers are selected according to different target materials, and the thickness of the functional layer can be further controlled by controlling the sputtering time, thereby achieving precise control of the thickness.

[0053] In some embodiments, the sputtering in steps S20 to S40 is performed under an inert gas protective atmosphere of 0.4-0.6 Pa; preferably, the inert gas includes but is not limited to one of nitrogen, helium, and argon.

[0054] In some embodiments, the annealing temperature is 200-800°C, and the annealing time is 0.5-8 hours. The purpose of annealing is to improve the crystallinity of the sample, and the sample is crystallized better using the highest possible temperature, but avoid excessively high temperatures that cause the sample to change from a ferromagnetic state to a paramagnetic state.

[0055] In some embodiments, in step S10, partially masking the substrate specifically includes: fixing the substrate on a magnetron sputtering sample stage by means of a high temperature resistant tape and masking a necessary area; exposing a portion of about 0.5-2 mm for connecting the electrode layer.

[0056] It should be noted that the order of step S40 and step S50 can be changed, and the sputtering preparation of the electrode layer can be performed after the annealing treatment.

[0057] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only used to illustrate the present invention but not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Example 1

[0059] This embodiment uses a grid-shaped striped indium tin oxide glass substrate to prepare a thin film in a magnetron sputtering device, and then performs a CVD tube furnace annealing process. The specific steps are as follows:

[0060] (1) Provide a grid-shaped striped indium tin oxide glass substrate with a specification of 20 mm*20 mm and 9 stripes, and use acetone, isopropanol, and anhydrous ethanol to ultrasonically clean the substrate for 20 minutes with an ultrasonic power of 100 W; after the cleaning is completed, use high-purity nitrogen to blow dry the silicon wafer; after completing the above steps, a clean substrate is obtained, and this step is to remove the influence of impurities on the sample performance.

[0061] (2) Figure 2 As shown, the substrate is pasted on the magnetron sputtering sample stage, and the necessary part of the substrate is covered with a high temperature resistant tape-PEN (polyethylene naphthalate). This step is to expose part of the conductive indium tin oxide so that the sample can be used as a photodetector.

[0062] (3) Provide a cobalt ferrite target with a purity of 99.99% as the ferromagnetic semiconductor layer; provide a cobalt oxide target with a purity of 99.99% as the antiferromagnetic semiconductor layer; use a magnetron sputtering device to sputter the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer in sequence; the sputtering power of the antiferromagnetic semiconductor layer is 90W, the sputtering pressure is 0.55Pa, and argon is used as the protective gas, and the sputtering time is 10 minutes; the sputtering power of the ferromagnetic semiconductor layer is 60W, the sputtering pressure is 0.55Pa, and argon is used as the protective gas, and the sputtering time is 60 minutes. After completion, take out the sample and remove the high temperature resistant tape-PEN. The schematic diagram of the obtained sample is as shown in Figure 3 This step is to make a ferromagnetic semiconductor / antiferromagnetic semiconductor double-layer heterojunction, which is the core step in making samples.

[0063] (4) The sample was placed in a CVD tube furnace for annealing at a temperature of 600°C for 2 hours, using argon as the protective gas.

[0064] (5) Electrodes were prepared using a mask with grid stripes, using a Ti / Au structure, with sputtering parameters of 100 W power, 0.55 Pa pressure in an argon atmosphere, 8 cm target-substrate distance, 18 s sputtering time for Ti, and 88 s sputtering time for Au. The schematic diagram of the obtained sample is as follows: Figure 4 This step is to make a gold electrode, which cooperates with the ITO exposed in step (2) to provide the sample with conditions for being used as a photodetector.

[0065] According to the above steps, the light response curve of the sample obtained by the 4200 probe station test is as follows Figure 5 As shown: the light response time is less than 0.02 seconds, and the photocurrent is 6.5*10 -10The sample has good photoelectric response performance, and the photocurrent and response of the sample have not changed much after 100 tests. The sample was placed in a comprehensive physical property measurement system to test the performance of the material, and the hysteresis loop - magnetic field size vs sample magnetization intensity curve was obtained, such as Figure 6 As shown, it can be seen that the sample has a strong exchange bias field of 12693.75 Oersteds; and after 10 training effect tests, the exchange bias field only fluctuates between 90% and 110% of the original. It can be seen that the thin film device obtained by this embodiment has good photoelectric response performance and a strong and stable exchange bias field.

[0066] Comparative Example 1

[0067] A cobalt metal target is provided as the ferromagnetic layer. The other steps are the same as in Example 1. A thin film sample is prepared on a silicon substrate using a magnetron sputtering device. Although the obtained sample has a good exchange bias field, it has no photoelectric detection performance.

[0068] Comparative Example 2

[0069] The same as Example 1, but eliminating step (4) in Example 1; the obtained sample does not have a strong and stable exchange bias field, and when used as a photodetector, there is a possibility that the sample will be damaged by a short circuit.

[0070] Example 2

[0071] The cobalt ferrite ferromagnetic semiconductor material provided in step (3) is replaced with nickel ferrite, nickel cobaltate, manganese-doped indium oxide, cobalt-doped zinc oxide, cobalt-doped titanium oxide, or an isotropic ferromagnetic semiconductor material; the rest is the same as in Example 1, and the prepared samples can obtain similar effects.

[0072] Example 3

[0073] The cobalt oxide antiferromagnetic semiconductor material provided in step (3) is replaced with iron-manganese alloy, manganese-gold alloy, manganese-nickel alloy, manganese-copper alloy, isotropic antiferromagnetic metal or alloy material; the rest is the same as in Example 1, and the finished sample can obtain similar effects.

[0074] Example 4

[0075] The cobalt ferrite ferromagnetic semiconductor material provided in step (3) is replaced with iron, cobalt, nickel, iron-chromium-cobalt, aluminum-nickel-cobalt, platinum-cobalt, iron-nickel Permalloy, isotropic ferromagnetic metals, and alloy materials; the cobalt oxide antiferromagnetic semiconductor metal material is replaced with nickel oxide, cobalt oxide, and other antiferromagnetic semiconductor metal materials with good photoelectric response; the rest is the same as in Example 1, and the prepared samples can obtain similar effects.

[0076] Example 5

[0077] The grid-shaped striped indium tin oxide glass substrate provided in step (1) is replaced with a full indium tin oxide glass conductive substrate; the grid-shaped striped mask provided in step (5) is replaced with a ring-shaped mask, a dot-shaped mask or other similar shapes; the rest is the same as in Example 1, and the finished sample can obtain similar effects.

[0078] Example 6

[0079] The grid-shaped striped indium tin oxide glass substrate provided in step (1) is replaced with a full indium tin oxide glass conductive substrate; the grid-shaped striped mask provided in step (5) is replaced with a ring-shaped mask, a dot-shaped mask or other similar shapes; or the sputtering time in step (5) is slightly changed; the rest is the same as in Example 1, and the finished sample can obtain similar effects.

[0080] Example 7

[0081] The annealing time in step (4) is changed to 2-4 hours, and the temperature is changed to 200-600 degrees Celsius; the other conditions are the same as those in Example 1, and the finished sample can obtain a similar but weaker effect.

[0082] Example 8

[0083] The sputtering time and sputtering power in step (3) are slightly changed; the other conditions are the same as those in Example 1, and the samples produced can obtain similar effects.

[0084] In summary, the present invention provides a thin film device with an exchange bias field and photoelectric detection performance and a preparation method thereof. The thin film device with an exchange bias field and photoelectric detection performance includes a substrate layer, an antiferromagnetic semiconductor layer, a ferromagnetic semiconductor layer, and an electrode layer stacked in sequence from bottom to top; the materials of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer have a photoelectric effect. The thin film device of the present invention not only has good photoelectric detection performance, but also has a strong exchange bias field; the exchange bias phenomenon originates from the double-layer film structure of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer, the magnetic moment of the ferromagnetic semiconductor layer is directly coupled with the uncancelled magnetic moment at the interface of the magnetic moment of the antiferromagnetic semiconductor layer, so that the ferromagnetic semiconductor layer is pinned, thereby forming an exchange bias phenomenon; and the photoelectric effect is a phenomenon that when a photon hits the surface of a material, it transfers energy to the electrons of the material, causing electrons to be emitted from atoms or molecules, and when electron holes are formed, the generation of these carriers causes current to flow, thereby generating an electrical signal proportional to the intensity of the incident light; when the ferromagnetic semiconductor layer and the antiferromagnetic semiconductor layer are prepared from materials with a photoelectric effect, the film not only has an exchange bias field, but also has a certain photoelectric detection capability. Specifically, the role of the substrate layer is to carry the device, and the conductive layer and the electrode layer on the substrate layer are simultaneously used as wires at both ends of the vertical film, so that the double-layer film becomes a photodiode, which has the conditions for photoelectric detection.

[0085] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A thin film device having exchange bias field and photodetection performance, characterized in that: It comprises a substrate layer, an antiferromagnetic semiconductor layer, a ferromagnetic semiconductor layer and an electrode layer which are stacked in sequence from bottom to top; the materials of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer have a photoelectric effect.

2. The thin film device with exchange bias field and photodetection performance according to claim 1, characterized in that: The material of the antiferromagnetic semiconductor layer includes one or more of cobalt oxide, nickel oxide, and manganese oxide.

3. The thin film device with exchange bias field and photodetection performance according to claim 1, characterized in that: The ferromagnetic semiconductor layer is a ferromagnetic material with a spinel structure; the ferromagnetic material includes one or more of cobalt ferrite, nickel ferrite, and chromium dioxide.

4. The thin film device with exchange bias field and photodetection performance according to claim 1, characterized in that: The material of the electrode layer includes an alloy formed by one or more of gold, platinum, silver, tantalum, palladium, titanium, copper, chromium, and molybdenum; and / or the substrate layer is a glass substrate with grid-shaped stripes of indium tin oxide, a glass substrate with fully conductive indium tin oxide, an indium tin oxide flexible substrate, a silicon dioxide substrate with a gold electrode, and an aluminum oxide substrate with a prefabricated electrode; the electrode layer is connected to the conductive layer on the substrate layer.

5. The thin film device with exchange bias field and photodetection performance according to claim 1, characterized in that: The ferromagnetic semiconductor layer may be replaced by a ferromagnetic metal layer or a ferromagnetic conductor layer.

6. The thin film device with exchange bias field and photodetection performance according to claim 1, characterized in that: The thickness of the antiferromagnetic semiconductor layer is between 5-200 nm; and / or the thickness of the ferromagnetic semiconductor layer is between 5-200 nm.

7. The thin film device with exchange bias field and photodetection performance according to claim 1, characterized in that: The thickness of the electrode layer is 5-80 nm; the thickness of the substrate layer is 0.5-2 mm.

8. A method for preparing a thin film device having exchange bias field and photoelectric detection performance as claimed in any one of claims 1 to 7, characterized in that: Includes steps: Providing a substrate, a ferromagnetic semiconductor material target, an antiferromagnetic semiconductor material target, and an electrode material target, and partially covering the substrate; Sputtering the antiferromagnetic semiconductor material target onto the substrate to obtain an antiferromagnetic semiconductor layer; Sputtering the ferromagnetic semiconductor material target onto the antiferromagnetic semiconductor layer to obtain a ferromagnetic semiconductor layer; removing the masked portion on the substrate, and sputtering the electrode material target onto the ferromagnetic semiconductor layer and the substrate to obtain a thin film device precursor; The thin film device precursor is annealed to obtain a thin film device.

9. The method for preparing a thin film device having exchange bias field and photoelectric detection performance according to claim 8, characterized in that: The sputtering power of sputtering the antiferromagnetic semiconductor material target onto the substrate is 75-120W, and the sputtering time is 1-15 minutes; the sputtering power of sputtering the ferromagnetic semiconductor material target onto the antiferromagnetic semiconductor layer is 50-80W, and the sputtering time is 30-90 minutes; the sputtering power of sputtering the electrode material target onto the ferromagnetic semiconductor layer and the substrate is 90-110W, and the sputtering time is 30-120 seconds.

10. The method for preparing a thin film device having exchange bias field and photoelectric detection performance according to claim 8, characterized in that: The temperature of the annealing treatment is 200-800° C., and the time of the annealing treatment is 0.5-8 hours.

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