Tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material as well as preparation method and application thereof

Abstract

The invention discloses a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material as well as a preparation method and application thereof, and belongs to the technical field of semiconductor material synthesis, an Mg3 (Sb, Bi) 2-based semiconductor material is prepared by adopting a mechanical alloying and hot pressing sintering method, the material is good in crystallinity, compact in structure and high in repeatability, the chemical formula of the material is Mg3. 4Bi1.3-xSb0.7 Tex (x is greater than or equal to 0 and less than or equal to 0.03), and the tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material is a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material. By optimizing the sintering process and doping the element Te, the thermal cycling stability and the air stability of the Mg3 (Sb, Bi) 2-based semiconductor material are remarkably improved, the conductivity is reduced by less than 5% after 20 times of cycling tests, and the room-temperature and high-temperature conductivity is basically unchanged after the Mg3 (Sb, Bi) 2-based semiconductor material is exposed in air for 20 days, so that the temperature range and the service life of the Mg3 (Sb, Bi) 2-based semiconductor material in practical application are widened.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor material synthesis, and in particular relates to a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material, a preparation method and an application thereof. Background Art

[0002] Semiconductor materials, as a special type of material between conductors and insulators, exhibit unique electrical and physical properties at room temperature. Its core characteristic lies in the controllability of its conductivity, which can be adjusted to any range between insulators and conductors as needed. This unique property gives semiconductor device circuits extraordinary flexibility and functionality, making semiconductor materials an indispensable basic material for the modern electronics industry.

[0003] The electrical and physical properties of semiconductor materials are the key to their widespread application. Through the doping process, specific elements can be added to semiconductor materials to accurately change and control their electrical properties. This controllability provides unlimited possibilities for the design and manufacture of semiconductor devices and promotes the rapid development of information technology. Common semiconductor materials, such as magnesium antimonide (Mg3Sb 2 ), lead sulfide (PbS), lead selenide (PbSe) and zinc sulfide (ZnS), etc., have been widely used in optoelectronic devices, solar cells, infrared detection and thermoelectric conversion due to their excellent performance, low price and high abundance of elements. However, despite their many advantages, these materials still face many challenges in practical applications.

[0004] As a potential thermoelectric material, the electrical conductivity of Mg3(Sb,Bi)2-based semiconductor materials can be significantly improved through a variety of methods. However, the thermal stability and air stability of the material have become key factors restricting its widespread application. Under high temperature and long-term service conditions, the high vapor pressure and high chemical activity of the Mg element cause serious deterioration of the material performance or even failure. In addition, the destruction of weak ionic bonds under high temperature and high pressure and the precipitation of the second phase Bi during thermal cycling further aggravate the fluctuation of the material's electrical properties. These unfavorable factors have severely restricted the progress of Mg3(Sb,Bi)2-based semiconductor materials in device applications.

[0005] In order to overcome the shortcomings of Mg3(Sb,Bi)2-based semiconductor materials in thermal stability and air stability, researchers have conducted a lot of exploration and attempts. However, despite some progress, existing solutions often have many limitations. For example, although some methods can improve the thermal stability of materials to a certain extent, they often sacrifice some thermoelectric properties. This means that while pursuing stability, the overall performance of the material has to be weighed, which limits its application potential in specific fields. In addition, the preparation process of some protective layers is complex and costly, which not only increases the difficulty of production, but also increases the application cost of the material. These factors jointly restrict the further promotion of Mg3(Sb,Bi)2-based semiconductor materials in practical applications. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention aims to provide a tellurium-doped magnesium antimony bismuth-based compound semiconductor material, a preparation method and an application. Only by simply adjusting the preparation process, a Mg3(Sb,Bi)2 semiconductor material with excellent thermal cycle stability and air stability is obtained. There is no need for complex methods such as long-term annealing and complex process for preparing coatings. This method has the advantages of simplicity, speed and low cost, so as to meet the preparation requirements of long-life semiconductor devices.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material, comprising the following steps: Under a protective atmosphere, metal Mg, metal Bi, metal Sb, metal Te and a grinding aid with a purity greater than 99.9% are mixed and then subjected to high-energy ball milling to obtain a metal mixed powder with an average particle size less than 5 μm; The metal mixed powder is subjected to hot pressing sintering, and after sintering, the temperature is lowered to 300°C at a cooling rate of 1°C / min to 3°C / min and then naturally cooled to obtain Mg3(Sb,Bi)2 semiconductor material; The chemical formula of the semiconductor material is Mg 3.4 Bi 1.3-x Sb 0.7 Te x , where x = 0.01~0.03.

[0008] Further, in a protective atmosphere, metal Mg, metal Bi, metal Sb, and metal Te with a purity greater than 99.9% are mixed and crushed to obtain a metal mixed powder with an average particle size less than 5 μm: Under the protection of high-purity argon, metal Mg, metal Bi, metal Sb, metal Te and grinding aids were mixed and high-energy ball milled. The rotation speed of the high-energy ball mill was 1200r / min~1400r / min, the ball milling time was 8h, the ball-to-material ratio was 10:1, and a metal mixed powder with an average particle size of less than 5μm was obtained.

[0009] Furthermore, during ball milling, metal Bi and metal Sb are pre-milled first, and then mixed with metal Mg and metal Te to continue ball milling.

[0010] Furthermore, the grinding aid is 1 wt% of stearic acid.

[0011] Furthermore, the metal mixed powder is hot pressed and sintered to obtain the Mg3(Sb,Bi)2 semiconductor material: the sintering temperature of the hot pressing and sintering is 800°C, the sintering heating rate is 10°C / min, the holding time is 2min, and the pressure is 60Mpa. Furthermore, when the sintering temperature reaches 200°C, pressure is applied, and the pressure growth rate is 2 Mpa / min. When the temperature reaches 500°C, the pressure reaches 60 Mpa.

[0012] Furthermore, the n The chemical formula of Mg3(Sb,Bi)2-based semiconductor materials is Mg 3.4 Bi 1.3-x Sb 0.7 Te x , where x=0.01.

[0013] The present invention also provides a magnesium antimony bismuth-based compound semiconductor material prepared by the above preparation method, wherein the electrical conductivity of the magnesium antimony bismuth-based compound semiconductor material reaches 763 S / cm~1044 S / cm at 323 K.

[0014] The present invention also provides a thermoelectric energy conversion device, which is prepared by using the above-mentioned tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material.

[0015] The present invention also provides a temperature sensor, which is prepared by using the above-mentioned tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The invention discloses a method for preparing a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material, wherein the chemical formula is Mg 3.4 Bi 1.3-x Sb 0.7 Te x, where x = 0 to 0.03, after mixing metal powders with a purity greater than 99.9%, Mg3(Sb,Bi)2 semiconductor materials were prepared by a simple mechanical alloying: ball milling, heating, pressing and sintering method. Compared with Mg3(Sb,Bi)2 semiconductor materials prepared by other doping and preparation methods, the Mg3(Sb,Bi)2 semiconductor materials prepared by the present invention have high thermal cycle stability and air stability. n The Mg3(Sb,Bi)2 semiconductor material has significantly improved the sintering quality and the thermal cycle stability and air stability of the material by adjusting the sintering process and adopting a slow cooling strategy during the preparation process. Then, by doping with Te, the high-valence element doping further increases the material carrier concentration and mobility, making it stable. n type conduction, ultimately achieving high thermal cycle stability and air stability n Type Mg3(Sb,Bi)2 semiconductor material. The results of the embodiment show that the present invention provides n The prepared Mg3(Sb,Bi)2-based semiconductor material has excellent electrical conductivity and a density of 91% to 95%. In the 20 thermal cycle tests, the average conductivity of the cycle decreased by less than 5%. In the air stability test, the electrical conductivity of the prepared Mg3(Sb,Bi)2-based semiconductor material did not show significant attenuation, indicating that the material has excellent air stability.

[0017] The present invention also discloses the application of the above-mentioned Mg3(Sb,Bi)2 semiconductor material with high electrical conductivity in the fields of thermoelectric energy conversion devices, temperature sensors, etc. When the Mg3(Sb,Bi)2 semiconductor material prepared by the present invention is used in the above-mentioned fields, the high thermal cycle stability and air stability can further increase the service life, thereby reducing costs and improving the cost performance of thermoelectric devices, etc., and enhancing the application in the fields of thermoelectric energy conversion, temperature sensors, etc. The excellent thermoelectric properties and stability of the Mg3(Sb,Bi)2 semiconductor material enable it to convert these large amounts of industrial waste heat into electrical energy, improve energy utilization efficiency, thereby reducing energy consumption and environmental pollution, and contributing to the sustainable development of human society. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention embodiment 2 is obtained by mechanical alloying n Type Mg 3.4 Bi 1.29 Sb 0.7 Te 0.01 Thermal cycling stability diagram of semiconductor materials; Figure 2 The present invention embodiment 2 is obtained by mechanical alloying n Type Mg 3.4 Bi 1.29 Sb0.7 Te 0.01 Air stability diagram of semiconductor materials; Figure 3 The present invention is obtained by mechanical alloying of Examples 1 to 4. n Type Mg 3.4 Bi 1.3-x Sb 0.7 Te x , where x = 0 ~ 0.03 conductivity diagram of semiconductor materials. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings: The present invention provides a novel thermal cycle stability and air stability n The method for preparing a type Mg3(Sb,Bi)2 semiconductor material comprises the following steps: Step 1) According to the chemical formula of Mg 3.4 Bi 1.3-x Sb 0.7 Te x , wherein x=0-0.03, weigh 2 g magnesium powder, 6.4226-6.5238 g bismuth powder, 2.063 g antimony powder, 0.0308-0.0926 g tellurium powder and 0.1057-0.1061 g stearic acid in an argon environment, put them into a ball mill, and mill them for 8 h using a high-energy ball mill at a speed of 1400 rpm / min to obtain metal powder; Preferably, the ball milling method is to rotate for 30 minutes, pause for 15 minutes, and repeat this process until the effective ball milling time is 8 hours.

[0022] Preferably, before ball milling, Sb powder and Bi powder are pre-milled for half an hour and then mixed and evenly ball-milled with Mg powder and Te powder to prevent side reactions and stably generate Mg3(Sb,Bi)2.

[0023] Step 2) The mixed metal powder obtained in step 1) is loaded into a hot-pressed graphite mold and sealed with carbon paper. The sintering temperature is 800°C, the sintering pressure is 60 MPa, the holding time is 2 min, and the cooling rate is 1~3°C / min to 300°C. After the pressure is removed, it is naturally cooled to finally obtain a bulk Mg3(Sb,Bi)2 semiconductor material.

[0024] Preferably, the pressure is applied when the sintering temperature reaches 200°C, the pressure increase rate is 2 Mpa / min, and when the temperature reaches 500°C, the pressure reaches 60 Mpa.

[0025] The preparation process of the present invention is simple and low in cost, and effectively improves n The thermal cycling stability and air stability of the Mg3(Sb,Bi)2-based semiconductor material. Compared with other doping and preparation methods, the Mg3(Sb,Bi)2 semiconductor material with high thermal cycling stability and air stability prepared by this sintering process has excellent electrical conductivity and a density of 91%~95%. In 20 thermal cycle tests, the average conductivity of the cycle decreased by less than 5%. In the air stability test, the electrical conductivity performance of the prepared Mg3(Sb,Bi)2-based semiconductor material did not show obvious attenuation, which indicates that the material has excellent air stability.

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Example 1 A method for preparing an n-type Mg3(Sb,Bi)2 semiconductor material with high thermal cycle stability and air stability, wherein the chemical formula is Mg 3.4 Bi 1.3 Sb 0.7 , specifically including the following steps: Step 1) Under an argon environment, 2 g of magnesium powder, 6.5711 g of bismuth powder, 2.063 g of antimony powder and 0.1074 g of stearic acid were weighed and put into a ball mill, and ball milled for 8 h using a high-energy ball mill at a speed of 1400 rpm / min to obtain a metal powder; Step 2) The mixed metal powder obtained in step 1) is placed in a spark plasma sintering mold, the sintering temperature is 800 °C, the sintering pressure is 60 MPa, the holding time is 2 min, the cooling rate is 1 °C / min to 300 °C and then naturally cooled to finally obtain a bulk Mg3(Sb,Bi)2 semiconductor material.

[0028] like Figure 3 As shown, the Mg prepared in this embodiment 3.4 Bi 1.3 Sb 0.7 The electrical conductivity of the semiconductor material reaches 253 S / cm at 323 K.

[0029] Example 2 A method for preparing an n-type Mg3(Sb,Bi)2 semiconductor material with high thermal cycle stability and air stability, wherein the chemical formula is Mg 3.4 Bi 1.29 Sb 0.7 Te 0.01 , specifically including the following steps: Step 1) Under an argon environment, 2 g of magnesium powder, 6.5238 g of bismuth powder, 2.063 g of antimony powder, 0.0308 g of tellurium powder and 0.1061 g of stearic acid were weighed and put into a ball mill for ball milling. The high-energy ball milling method was used for 8 h at a speed of 1400 rpm / min to obtain metal powder; Step 2) The mixed metal powder obtained in step 1) is placed in a spark plasma sintering mold, the sintering temperature is 800 °C, the sintering pressure is 60 MPa, the holding time is 2 min, the cooling rate is 1 °C / min to 300 °C and then naturally cooled to finally obtain a bulk Mg3(Sb,Bi)2 semiconductor material.

[0030] like Figure 3 As shown, the Te-doped Mg prepared in this embodiment 3.4 Bi 1.29 Sb 0.7 Te 0.01 The electrical conductivity of the semiconductor material reaches 763 S / cm at 323 K.

[0031] Example 3 A method for preparing an n-type Mg3(Sb,Bi)2 semiconductor material with high thermal cycle stability and air stability, wherein the chemical formula is Mg 3.4 Bi 1.28 Sb 0.7 Te 0.02 , specifically including the following steps: Step 1) Under an argon environment, 2 g of magnesium powder, 6.4732 g of bismuth powder, 2.063 g of antimony powder, 0.0616 g of tellurium powder and 0.1059 g of stearic acid were weighed and put into a ball mill for ball milling. The high-energy ball milling method was used for 8 h at a speed of 1400 rpm / min to obtain metal powder; Step 2) The mixed metal powder obtained in step 1) is placed in a spark plasma sintering mold, the sintering temperature is 800 ° C, the sintering pressure is 60 MPa, the holding time is 2 min, the cooling rate is 2 ° C / min to 300 ° C and then naturally cooled to finally obtain a bulk Mg3(Sb,Bi)2 semiconductor material.

[0032] The Te-doped Mg prepared in this example is characterized. 3.4 Bi 1.28 Sb 0.7 Te 0.02 The electrical conductivity of the semiconductor material reaches 912 S / cm at 323 K.

[0033] Example 4 A method for preparing an n-type Mg3(Sb,Bi)2 semiconductor material with high thermal cycle stability and air stability, wherein the chemical formula is Mg 3.4 Bi 1.27 Sb 0.7 Te 0.03 , specifically including the following steps: Step 1) Under an argon environment, 2 g of magnesium powder, 6.4226 g of bismuth powder, 2.063 g of antimony powder, 0.0926 g of tellurium powder and 0.1057 g of stearic acid were weighed and put into a ball mill for ball milling. The high-energy ball milling method was used for 8 h at a speed of 1400 rpm / min to obtain metal powder; Step 2) The mixed metal powder obtained in step 1) is placed in a spark plasma sintering mold, the sintering temperature is 800 °C, the sintering pressure is 60 MPa, the holding time is 2 min, the cooling rate is 3 °C / min to 300 °C, and then naturally cooled to finally obtain a bulk Mg3(Sb,Bi)2 semiconductor material.

[0034] like Figure 3 As shown, the Te-doped Mg prepared in this embodiment 3.4 Bi1.27 Sb 0.7 Te 0.03 The electrical conductivity of the semiconductor material reaches 1044 S / cm at 323 K.

[0035] like Figure 1 As shown in FIG. 1 , in the embodiment, the average conductivity decrease of the cycle is less than 5% in the 20 times thermal cycle test. Figure 2 In the air stability test, the conductivity of the prepared Mg3(Sb,Bi)2-based semiconductor material showed no obvious attenuation after exposure to air for 20 days, which indicates that the material has excellent air stability.

[0036] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material, characterized in that: The following steps are involved: Under a protective atmosphere, metal Mg, metal Bi, metal Sb, metal Te and a grinding aid with a purity greater than 99.9% are mixed and then subjected to high-energy ball milling to obtain a metal mixed powder with an average particle size less than 5 μm; The metal mixed powder is subjected to hot pressing sintering, and after sintering, the temperature is lowered to 300°C at a cooling rate of 1°C / min to 3°C / min and then naturally cooled to obtain Mg3(Sb,Bi)2 semiconductor material; The chemical formula of the semiconductor material is Mg 3.4 Bi 1.3-x Sb 0.7 Te x , where x = 0.01~0.

03.

2. The method for preparing a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material according to claim 1, characterized in that: In a protective atmosphere, metal Mg, metal Bi, metal Sb and metal Te with a purity greater than 99.9% are mixed and then crushed to obtain a metal mixed powder with an average particle size less than 5 μm: Under the protection of high-purity argon, metal Mg, metal Bi, metal Sb, metal Te and grinding aids were mixed and high-energy ball milled. The rotation speed of the high-energy ball mill was 1200r / min~1400r / min, the ball milling time was 8h, the ball-to-material ratio was 10:1, and a metal mixed powder with an average particle size of less than 5μm was obtained.

3. The method for preparing a tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material according to claim 1, characterized in that: When ball milling is performed, metal Bi and metal Sb are pre-milled first, and then mixed with metal Mg and metal Te and continued to be ball milled.

4. The method for preparing a tellurium-doped magnesium antimony-bismuth-based compound semiconductor material according to claim 1, characterized in that: The grinding aid is 1 wt% of stearic acid.

5. The method for preparing a tellurium-doped magnesium antimony-bismuth-based compound semiconductor material according to claim 1, characterized in that: In the step of hot pressing and sintering the metal mixed powder to obtain the Mg3(Sb,Bi)2 semiconductor material: the sintering temperature of the hot pressing and sintering is 800°C, the sintering heating rate is 10°C / min, the holding time is 2min, and the pressure is 60Mpa.

6. The method for preparing a tellurium-doped magnesium antimony-bismuth-based compound semiconductor material according to claim 1, characterized in that: When the sintering temperature reaches 200°C, pressure begins to be applied, with a pressure increase rate of 2 Mpa / min. When the temperature reaches 500°C, the pressure reaches 60 Mpa.

7. The method for preparing a tellurium-doped magnesium antimony-bismuth-based compound semiconductor material according to claim 1, characterized in that: Said n The chemical formula of Mg3(Sb,Bi)2-based semiconductor materials is Mg 3.4 Bi 1.3-x Sb 0.7 Te x , where x=0.

01.

8. The magnesium antimony bismuth-based compound semiconductor material obtained by the preparation method according to claims 1 to 7, characterized in that: The electrical conductivity of the magnesium antimony bismuth-based compound semiconductor material reaches 763 S / cm~1044 S / cm at 323 K.

9. A thermoelectric energy conversion device, characterized in that: The method is prepared by using the tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material described in claim 8.

10. A temperature sensor, characterized in that: The method is prepared by using the tellurium-doped magnesium-antimony-bismuth-based compound semiconductor material described in claim 8.

Images