Magnetic semiconductor material and method for producing the same

Abstract

The application relates to the field of spin electronics materials, in particular to a magnetic semiconductor material and a preparation method thereof. 1‑y C y X3, wherein y=0-0.1, A is one of Ca, Sr and Ba, B is one of Ti, Zr and Hf, X is S or Se, and C is one of Mn, Fe and Co; since the chalcogenide perovskite has a similar chemical formula and structure to the oxide perovskite, when the oxygen ions in the oxide perovskite are replaced by chalcogen (S, Se) ions, the structure of the chalcogenide perovskite will be distorted, thereby causing significant changes in the electronic structure, and accordingly the band gap width and photoelectric properties will also change. The 3d transition metal C (Mn, Fe, Co) with a local magnetic moment is used to replace the B-site cations, and the material can exhibit long-range magnetic order. Therefore, the chalcogenide magnetic semiconductor material designed and prepared by the application greatly enriches the selectivity of the magnetic semiconductor material, thereby providing the possibility for designing new high-curie-point spin electronics materials and devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spintronics materials, in particular to a kind of magnetic semiconductor material and preparation method thereof. BACKGROUND

[0002] Semiconductor spintronics uses the degree of freedom of electron spin for logic operation and information storage, providing new possibilities for beyond-CMOS electronic devices. One important class of materials in spintronics is magnetic semiconductors, which possess both magnetic and semiconducting properties, and can simultaneously control the charge and spin properties of electrons, realizing logic and storage functions, and providing attractive application prospects for electronic devices.

[0003] Magnetic semiconductor materials have shown broad application prospects. For example, magnetic semiconductor materials can be used as electrodes to realize the injection of spin-polarized carriers into non-magnetic semiconductors to solve the problem of resistance mismatch between magnetic metal electrodes and semiconductors; they can also be used in the manufacture of spin-polarized light-emitting diodes. For certain ferromagnetic layer / non-magnetic layer multilayer heterostructures, such as GaMnAs / AlGaAs / GaMnAs, by adjusting external parameters such as temperature and electric field, the carrier concentration in the semiconductor layer and the magnetic coupling between the magnetic layers can be controlled, and this property can be applied to the manufacture of new superlattice devices such as magnetic control and light control. However, the magnetic moment and Curie temperature of conventional magnetic semiconductors are low, limiting their practical applications. Therefore, improving the Curie temperature of magnetic semiconductors and exploring new magnetic semiconductor materials have become a hot topic in the field of semiconductor spintronics.

[0004] Chalcogenide perovskites (ABX3, where A=Ca 2+ , Sr 2+ , Ba 2+ ; B=Ti 4+ , Zr 4+ , Hf 4+ ; X=S 2- , Se 2- ) are a new class of semiconductor functional materials with unique electronic structure and photoelectric properties. Recent theoretical and experimental results have shown that this class of materials is a direct band gap semiconductor with high optical absorption coefficient, and its band gap is much smaller than that of the corresponding oxide perovskite, so it has strong absorption in the visible and infrared regions. The rare combination of strong light absorption and good carrier transport properties makes chalcogenide perovskites have great potential as photoelectric materials. If magnetic order is introduced into chalcogenide perovskites, their Curie temperature and magnetic moment can be controlled, and it is possible to select magnetic semiconductors with high transition temperature. For example, by replacing the B-site cations in chalcogenide perovskite materials with 3d transition metal ions with local magnetic moments, the material can exhibit long-range magnetic order.

[0005] In summary, it is still a technical problem to design and obtain a controllable magnetic semiconductor material with high Curie point and stable performance. SUMMARY

[0006] The application aims to design and obtain a novel magnetic semiconductor material. The application obtains a chalcogenide perovskite semiconductor by a solid phase reaction method and a chemical atmosphere sintering method, introduces ferromagnetism in the chalcogenide perovskite semiconductor by substituting B-site cations with 3d transition metal having a local magnetic moment, and realizes the regulation of the magnetism of the material by changing the doping amount of the doping metal.

[0007] To solve the above technical problems, the technical scheme adopted by the application is as follows: a magnetic semiconductor material with a chemical formula of AB 1-y C y X3, wherein y=0-0.1, A is one of Ca, Sr and Ba, B is one of Ti, Zr and Hf, X is S or Se, and C is one of Mn, Fe and Co.

[0008] In addition, the application further provides a preparation method of the magnetic semiconductor material, comprising the following steps:

[0009] 1) ingredients are prepared according to stoichiometric ratios, raw materials are oxides or carbonates of corresponding metals (such as BaCO3, ZrO2 and MnO2, etc.), and the raw materials are mixed and then placed in a ball mill for ball milling and sufficient mixing;

[0010] 2) the mixture of step 1) is calcined in a muffle furnace, and a solid phase reaction method is adopted to obtain chalcogenide perovskite oxide powder;

[0011] 3) the perovskite oxide powder of step 2) is subjected to high-temperature sulfuration in a tube furnace, CS2 is used as a sulfur source and argon is used as a carrier gas during the sulfuration process, CS2 is started to be passed when the temperature is higher than 800℃, and the sulfuration is ended when the temperature is lower than 800℃, and the magnetic semiconductor material is obtained after sulfuration.

[0012] Further, the purity of the raw materials used in step 1) is greater than or equal to 99.9%, the amount of the raw materials is determined according to the stoichiometric relationship (such as the molar ratio Ba: (Zr+Mn) = 1:1), and the type of the ball mill used is F-P400.

[0013] Further, the type of the muffle furnace used in step 2) is KSL-1500X-S, the calcination temperature is 1200℃, and the calcination time is 6h.

[0014] Further, the perovskite oxide powder in step 3) is placed in a quartz boat, and the type of the tube furnace used is GSK16-1.

[0015] Further, the purity of the CS2 in step 3) is greater than or equal to 99.9%, and the purity of the argon is greater than or equal to 99.9%.

[0016] Further, in the sulfuration process of step 3), a sodium hydroxide solution is used as a tail gas treatment solution.

[0017] Further, the concentration of the sodium hydroxide solution is 1 mol / L.

[0018] In addition, the application also provides an application of the above-mentioned magnetic semiconductor material or the magnetic semiconductor material prepared by the above-mentioned preparation method in high Curie point spin electronics materials and devices.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] Since the chalcogenide perovskite has a similar chemical formula and structure to the oxide perovskite, when the oxygen ions in the oxide perovskite are replaced by chalcogen (S, Se) ions, the structure of the oxide perovskite will be distorted, which will cause a significant change in the electronic structure, and accordingly, the band gap width and the photoelectric properties will also change. And the B-site cations are replaced by 3d transition metal C (Mn, Fe, Co) with a local magnetic moment, and the material can exhibit long-range magnetic order. Therefore, the chalcogenide magnetic semiconductor material designed and prepared by the application greatly enriches the selectivity of magnetic semiconductor materials, thereby providing the possibility for designing new high Curie point spin electronics materials and devices. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is BaZr 1-y Mn y X-ray diffraction patterns of S3 (y=0, 0.01, 0.02, 0.03 and 0.05) powders.

[0022] Figure 2 is BaZr 1-y Fe y X-ray diffraction patterns of S3 (y=0, 0.02 and 0.05) powders.

[0023] Figure 3 is BaZr 1-y Co y X-ray diffraction patterns of S3 (y=0, 0.02 and 0.05) powders.

[0024] Figure 4 is BaZr 1-y Mn y SEM and EDX test patterns of S3 (y=0-0.1) powders.

[0025] Figure 5 BaZr 1-y Mn y S3(y=0, 0.01, 0.02, 0.03 and 0.05), BaZr 1-y Fe y S3(y=0, 0.02 and 0.05) and BaZr 1-y Co y UV-vis test spectrum of BaZr

[0026] Figure 6 BaZr 1-y Mn y S3(y=0, 0.01, 0.02, 0.03 and 0.05), BaZr 1-y Fe y S3(y=0, 0.02 and 0.05) and BaZr 1-y Co y Magnetic test spectrum of BaZr DETAILED DESCRIPTION

[0027] The application will be further described below in combination with specific embodiments.

[0028] A method for preparing a magnetic semiconductor material, comprising the following steps:

[0029] Step S1, taking ACO3, BO2, C y O x As the reaction raw material, a solid phase reaction method is used to calcine to obtain the corresponding oxide powder AB 1-y C y O3(y=0-0.1), wherein A= Ca, Sr, Ba; B=Ti, Zr, Hf; C=Mn, Fe, Co.

[0030] The specific steps of the solid phase reaction method are as follows:

[0031] Step S11, the reaction raw material is weighed according to the stoichiometric ratio, and the total weight is 10g, which is added to the ball mill tank, 10ml of alcohol is added, and then it is placed in the ball mill for ball milling to fully mix, the ball milling speed is 450r / min, and the ball milling time is 3-4h;

[0032] Step S12, after the ball milling, the powder is taken out, dried completely, and then placed in a crucible, compacted, and put into a muffle furnace for calcination. The calcination temperature is 1200℃, the calcination time is 6h, and the heating rate is 4-5℃ / min, thereby obtaining the corresponding oxide powder of the chalcogen perovskite phase.

[0033] Step S2, the product obtained in step S1 is subjected to sulfurization treatment. The specific steps of the sulfurization treatment are as follows:

[0034] Step S21, the product obtained in step S1 is taken out, ground in a mortar, weighed 4g in a quartz boat, and placed into the chemical vapor deposition furnace. The second gas valve is opened, argon is introduced until the oxygen in the furnace is exhausted, the chemical vapor deposition furnace is started to heat, and the heating rate is 4-5℃ / min. When the temperature rises to 800℃, the second gas valve is closed and the first gas valve is opened. Argon is introduced into the cold trap containing CS2 solution as the sulfur source, and the gas flow is set to 14-16ml / min.

[0035] Step S22, when the temperature rises to 1000-1100℃, keep for 6h;

[0036] Step S23, when the temperature in the furnace drops to 800℃, the first gas valve is closed and the second gas valve is opened. Argon is introduced into the chemical vapor deposition furnace until the temperature in the furnace drops to room temperature, thereby obtaining the chalcogen magnetic semiconductor material.

[0037] wherein, when CS2 solution is used as the sulfur source, the corresponding oxide powder of the chalcogen perovskite phase is AB 1-y C y O3(y=0-0.1) reacts as follows: AB 1-y C y O3 + CS2 = AB 1-y C y S3 + CO2.

[0038] Example 1

[0039] 1. BaCO3, ZrO2, and MnO2 powders are weighed according to the stoichiometric relationship, a total of 10g, for preparing BaZr 1-y Mn y O3(BaZr 1-y Fe y O3 / BaZr 1-y Co y O3), are added to a ball milling tank, 10ml of alcohol is added, and then placed in a ball mill for 3h at a rotation speed of 450r / min.

[0040] 2. After the powder is dried, it is placed in a crucible, compacted, and placed in a muffle furnace for calcination. The calcination temperature is 1200°C, the calcination time is 6h, and the temperature rising time is 4h;

[0041] 3. The product after the solid phase reaction is taken out, ground thoroughly, 4g of the powder is weighed into a quartz boat and placed into the chemical vapor deposition furnace. The second gas valve is opened and argon is introduced until the furnace is empty of oxygen;

[0042] 4. The chemical vapor deposition furnace is heated at a temperature rising rate of 5°C / min. When the temperature in the furnace rises to 800°C, the second gas valve is closed and the first gas valve is opened. The gas flow is set to 16ml / min. When the temperature in the furnace rises to 1050°C, it is held for 6h;

[0043] 5. After the holding time ends, when the temperature in the furnace falls to 800°C, the first gas valve is closed and the second gas valve is opened. Argon is introduced into the chemical vapor deposition furnace until the temperature in the furnace falls to room temperature to obtain BaZr 1-y Mn y S3 powder.

[0044] Example 2

[0045] The procedure is the same as in Example 1, except that MnO2 is replaced by Fe3O4. BaZr 1-y Fe y S3 powder is prepared.

[0046] Example 3

[0047] The procedure is the same as in Example 1, except that MnO2 is replaced by Co2O3. BaZr 1-y Co y S3 powder is prepared.

[0048] Figures 1-3 X-ray diffraction patterns of BaZr 1-y Mn y S3, BaZr 1-y Fe y S3, BaZr 1-y Co y S3) powder prepared in Examples 1-3.

[0049] Figure 4 SEM and EDX test patterns of BaZr 1-y Mn y S3 (y=0-0.1) powder prepared in Example 1. Figure 4 It can be seen that Mn is indeed doped into BaZrS3, and the sample has good crystallinity.

[0050] Figure 5BaZrS3 1-y Mn y S3(y=0, 0.01, 0.02, 0.03 and 0.05), BaZr 1-y Fe y S3(y=0, 0.02 and 0.05) and BaZr 1-y Co y S3(y=0, 0.02 and 0.05) powders. From the UV-vis test spectrum of Figure 5 It can be seen that the band gap of BaZrS3 semiconductor material can be controlled by doping different components, and the three magnetic metal materials are first used to control the transition metal chalcogen perovskite semiconductor material by doping, which greatly expands the range of optional materials for controlling the band gap of transition metal chalcogen perovskite semiconductor materials.

[0051] Figure 6 BaZrS3 1-y Mn y S3(y=0, 0.01, 0.02, 0.03 and 0.05), BaZr 1-y Fe y S3(y=0, 0.02 and 0.05) and BaZr 1-y Co y S3(y=0, 0.02 and 0.05) powders. From the UV-vis test spectrum of Figure 6 It can be seen that the introduction of magnetic elements greatly changes the magnetic properties of non-magnetic semiconductor materials, and different magnetic elements produce different magnetic properties, and the introduction of iron elements makes the chalcogen perovskite semiconductor material have obvious magnetic hysteresis loop at room temperature, which shows room temperature ferromagnetism. The introduction of different magnetic elements expands the research range of magnetic semiconductor materials.

[0052] From the above examples, a new type of magnetic semiconductor material is designed, and the prepared chalcogen perovskite semiconductor shows high quality perovskite phase and good crystallinity. The material has good light absorption property and is a direct band gap semiconductor. By partially doping B site with 3d transition group metal with local magnetic property, the material shows ferromagnetism. By changing the doping metal and doping amount, the semiconductor property and ferromagnetism can be controlled. Therefore, the chalcogen magnetic semiconductor material obtained by the application can be applied in high Curie point spin electronics materials and devices.

Claims

1. A magnetic semiconductor material with the chemical formula AB 1-y C y X3, where y = 0 - 0.1 and y > 0, A is one of Ca, Sr and Ba, B is one of Ti, Zr and Hf, X is S or Se, and C is one of Mn, Fe and Co.

2. A method for preparing the magnetic semiconductor material as described in claim 1, characterized in that, Includes the following steps: 1) Prepare the ingredients according to the stoichiometric ratio. The raw materials are oxides or carbonates of the corresponding metals. After mixing the raw materials, place them in a ball mill for ball milling to ensure thorough mixing. 2) The mixture from step 1) is calcined in a muffle furnace to obtain the corresponding oxide powder of chalcogenide perovskite by solid-state reaction method; 3) The oxide powder from step 2) is subjected to high-temperature sulfidation in a tube furnace. CS2 is used as the sulfur source and argon is used as the carrier gas during the sulfidation process. CS2 is introduced when the temperature is above 800℃; CS2 is introduced when the temperature is below 800℃ after sulfidation. The magnetic semiconductor material is obtained after sulfidation.

3. The method according to claim 2, characterized in that, Step 1) The purity of the raw materials used is greater than or equal to 99.9%; the model of the ball mill used is F-P400, the ball milling speed is 450 r / min, and the ball milling time is 3-4 h.

4. The method according to claim 2, characterized in that, In step 2), the muffle furnace model is KSL-1500X-S; the calcination temperature is 1200℃ and the calcination time is 6h.

5. The method according to claim 2, characterized in that, In step 3), the oxide powder is placed in a quartz boat, and the tube furnace is model GSK16-1.

6. The method according to claim 2, characterized in that, Step 3) The purity of CS2 is greater than or equal to 99.9%, and the purity of argon is greater than or equal to 99.9%.

7. The method according to claim 2, characterized in that, In step 3), sodium hydroxide solution is used as the exhaust gas treatment solution during the sulfidation process.

8. The method according to claim 7, characterized in that, The concentration of the sodium hydroxide solution is 1 mol / L.

9. The application of a magnetic semiconductor material as described in claim 1 or a magnetic semiconductor material prepared by the method of any one of claims 2-8 in high Curie point spintronic materials or devices.

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