Tellurium-based heterojunctions and electroluminescent devices

Abstract

The application discloses a tellurium-based heterojunction and an electroluminescent device, the tellurium-based heterojunction comprising a tellurium nanolayer and a hetero layer different from the tellurium nanolayer, the tellurium nanolayer and the hetero layer being at least partially laminated; wherein the hetero layer can inject electrons into the tellurium nanolayer under the action of a bias voltage, and the electrons injected into the tellurium nanolayer can recombine with holes in the tellurium nanolayer to generate mid-infrared radiation. The tellurium-based heterojunction and the electroluminescent device provided by the application can realize efficient recombination of electrons and holes in the tellurium nanolayer by combining the tellurium nanolayer with a specific hetero layer to form a new hetero structure, can generate polarization-adjustable mid-infrared radiation, and can solve the compatibility problem with a silicon substrate; meanwhile, the use of tellurium as a main material can simplify the preparation process, improve the environmental stability of the device, and thus widen the application range of mid-infrared LED technology.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a tellurium-based heterojunction and an electroluminescent device. Background Technology

[0002] Mid-infrared light-emitting diodes (Mid-IR LEDs) are widely used in fields such as spectral analysis, environmental monitoring, and medical diagnostics. Currently, mid-infrared LED technology is mainly based on the quantum cascade structure of group III-V or group II-VI materials. These materials, such as indium antimonide (InSb), indium antimonide arsenide (InAsSb), and lead salts, are prepared through epitaxial growth processes.

[0003] However, existing mid-infrared LED technology has many limitations. First, group III-V and group II-VI materials are incompatible with silicon substrates. As one of the most commonly used semiconductor materials, silicon's incompatibility with the aforementioned mid-infrared emitting materials limits the application of mid-infrared LEDs in silicon-based integrated circuits.

[0004] Secondly, the epitaxial processes required to fabricate these materials are highly complex. The fabrication of quantum cascade structures demands extremely high precision, which not only increases the technical difficulty of production but also significantly raises manufacturing costs. These increased costs pose a major obstacle to commercial applications, limiting the widespread adoption and application of mid-infrared LED technology.

[0005] In addition, group III-V and II-VI materials also have limitations in terms of environmental stability and durability. These materials may be sensitive to environmental conditions, which could affect the long-term stability and performance of devices. Therefore, it is necessary to provide a new solution to address the aforementioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a tellurium-based heterojunction and an electroluminescent device that is compatible with silicon substrates and has a simple fabrication method.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] In a first aspect, the present invention provides a tellurium-based heterojunction comprising a tellurium nanolayer and a heterostructure heterogeneous to the tellurium nanolayer, wherein the tellurium nanolayer and the heterostructure are at least partially stacked; wherein the heterostructure is capable of injecting electrons into the tellurium nanolayer under a bias voltage, and the injected electrons can recombine with holes in the tellurium nanolayer to generate mid-infrared radiation.

[0009] In one or more embodiments, the heterolayer includes a molybdenum disulfide nanolayer that is at least partially stacked with the tellurium nanolayer.

[0010] In one or more embodiments, the molybdenum disulfide nanolayer is capable of injecting electrons into the tellurium nanolayer under a forward bias voltage greater than 1.5V and a positive gate voltage of 55–75V.

[0011] In one or more embodiments, the thickness of the molybdenum disulfide nanolayer is 8–20 nm, and the thickness of the tellurium nanolayer is 50–100 nm.

[0012] In one or more embodiments, the heterolayer includes a thin graphene nanolayer and a thick graphene nanolayer that are at least partially stacked with the tellurium nanolayer, the thin graphene nanolayer and the thick graphene nanolayer being disposed on the upper surface and lower surface of the tellurium nanolayer, respectively.

[0013] In one or more embodiments, the thin graphene nanolayer and the thick graphene nanolayer are capable of injecting holes and electrons into the tellurium nanolayer, respectively, under a forward bias voltage greater than 1.5V.

[0014] In one or more embodiments, the thin graphene nanolayer is a single layer or a double layer, the thick graphene nanolayer has 5 to 10 layers, and the thickness of the tellurium nanolayer is 270-450 nm.

[0015] In a second aspect, the present invention provides an electroluminescent device comprising a substrate layer and a dielectric layer stacked thereon, wherein a tellurium nanolayer and a heterogeneous layer heterogeneous to the tellurium nanolayer are disposed on the dielectric layer, and the tellurium nanolayer is at least partially stacked on the upper surface of the heterogeneous layer.

[0016] The heterolayer can inject electrons into the tellurium nanolayer under a bias voltage. The injected electrons can recombine with holes in the tellurium nanolayer to generate mid-infrared radiation.

[0017] In one or more embodiments, the tellurium nanolayer is electrically connected to a positive electrode, and the heterolayer is electrically connected to a negative electrode.

[0018] In one or more embodiments, the substrate layer is a silicon substrate, and the dielectric layer is a 285 nm thick silicon dioxide layer.

[0019] Compared with existing technologies, the tellurium-based heterojunction and electroluminescent device provided by this invention utilizes a combination of tellurium nanolayers and specific heterolayers to form a novel heterostructure. This structural design enables efficient recombination of electrons and holes in the tellurium nanolayers, generating mid-infrared radiation with polarization characteristics, and also solves the compatibility problem with silicon substrates. At the same time, using tellurium as the main material simplifies the fabrication process and improves the environmental stability of the device, thereby broadening the application range of mid-infrared LED technology. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a tellurium-based heterojunction in one embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of a tellurium-based heterojunction in another embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of an electroluminescent device according to one embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the structure of the electroluminescent device prepared in Embodiment 1 of the present invention;

[0025] Figure 5 This is a schematic diagram of the energy band of the Te-MoS2 heterojunction in Embodiment 1 of the present invention when no external bias or gate voltage is applied;

[0026] Figure 6 This is a schematic diagram of the energy band structure of the Te-MoS2 heterojunction in Embodiment 1 of the present invention when an external positive bias voltage and a positive gate voltage are applied.

[0027] Figure 7 The images show the electroluminescence signal and polarized electroluminescence of the Te-MoS2 heterojunction in Embodiment 1 of the present invention when an external forward bias voltage and a positive gate voltage are applied.

[0028] Figure 8 This is a polarization electroluminescence pattern of the Te-MoS2 heterojunction in Embodiment 1 of the present invention;

[0029] Figure 9 This is a schematic diagram of the structure of the electroluminescent device obtained in Embodiment 2 of the present invention;

[0030] Figure 10 This is an electroluminescence signal diagram of the Gr-Te-Gr heterojunction in Embodiment 2 of the present invention when an external forward bias voltage is applied;

[0031] Figure 11 This is a polarization electroluminescence pattern of the Gr-Te-Gr heterojunction in Embodiment 2 of the present invention;

[0032] Figure 12This is an electroluminescence signal diagram of the Te-MoS2 heterojunction in Comparative Example 1 of the present invention when an external reverse bias voltage and a negative gate voltage are applied. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0034] It should be noted that, unless otherwise specified, all figures used in this specification and claims to represent feature dimensions, quantities, and physical properties should be understood to be modified by the term "about" in all cases. Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics using the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.2, 1.4, 1.55, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0035] Current technologies primarily rely on group III-V or group II-VI materials to construct quantum cascade structures. However, these technologies suffer from significant limitations in terms of compatibility with silicon substrates, fabrication complexity, and environmental stability. These limitations not only hinder the widespread application of mid-infrared LED technology but also restrict further performance improvements.

[0036] Based on an analysis of existing technologies, the inventors realized that the aforementioned problems could be effectively overcome by changing the traditional choices of materials and structures. Therefore, the technical approach of this invention lies in developing a novel tellurium-based heterostructure, aiming to solve the core problems in existing technologies.

[0037] The core idea of ​​this invention lies in combining tellurium nanolayers with specific heterostructures to form a novel heterostructure. This structural design not only facilitates efficient recombination of electrons and holes, generating mid-infrared radiation, but also solves the compatibility problem with silicon substrates. Furthermore, using tellurium as the main material simplifies the fabrication process, reduces costs, and improves environmental stability, thereby broadening the application scope of mid-infrared LED technology.

[0038] like Figure 1As shown, a tellurium-based heterojunction in one embodiment of the present invention includes a tellurium nanolayer 11 and a heterolayer 12 that is heterogeneous to the tellurium nanolayer 11. The tellurium nanolayer 11 and the heterolayer 12 are at least partially stacked. The heterolayer 12 can inject electrons into the tellurium nanolayer 11 under a bias voltage. The injected electrons can recombine with holes in the tellurium nanolayer 11 to generate mid-infrared radiation with linear polarization characteristics.

[0039] It should be noted that when a bias voltage (e.g., a forward bias voltage) is applied, the heterolayer 12, as an n-type semiconductor (or a material with similar properties), injects electrons into the tellurium nanolayer 11 (a p-type semiconductor or a material with similar properties). This is because under a forward bias voltage, the Te-MoS2 heterojunction undergoes band bending, causing electrons to cross a small potential barrier from the conduction band of the n-type material into the conduction band of the p-type material.

[0040] When electrons are injected from heterolayer 12 into the conduction band of tellurium nanolayer 11, they encounter holes in the valence band of tellurium nanolayer 11. Electron-hole recombination is an energy-releasing process, which is released in the form of light. Since tellurium is a quasi-direct bandgap semiconductor material with a bandgap of ~0.34 eV, its emission wavelength is close to that of black phosphorus, located within the 3-5 μm atmospheric window in the mid-infrared band. When electrons injected into the conduction band of tellurium nanolayer 11 encounter holes in the valence band, radiative recombination occurs; that is, the electron jumps from the conduction band to the valence band, releasing a photon with energy equal to the bandgap width, forming mid-infrared radiation. The generated mid-infrared radiation has linear polarization characteristics, and the degree of polarization can be changed with the magnitude of the applied voltage.

[0041] In one exemplary embodiment, the heterolayer 12 includes a molybdenum disulfide nanolayer at least partially stacked with the tellurium nanolayer 11. MoS2 is an n-type semiconductor material with a band gap of ~1.8 eV, enabling it to form a transcontinental (Type-I) band arrangement with Te, which is crucial for the operation of light-emitting diodes. MoS2 has high electron mobility, allowing electrons to move efficiently within the material under the influence of an electric field.

[0042] Furthermore, the surface of MoS2 lacks dangling bonds, allowing it to be readily bonded to other materials (such as tellurium nanolayers 11) without affecting its performance or stability due to chemical reactions caused by surface dangling bonds. MoS2 can be integrated onto silicon (Si) substrates via van der Waals forces. Van der Waals force transfer is a method for forming weak chemical bonds between two materials, enabling the formation of stable thin films of MoS2 on silicon substrates without lattice mismatch issues.

[0043] Specifically, the molybdenum disulfide nanolayer can inject electrons into the tellurium nanolayer 11 under a forward bias voltage greater than 1.5V and a positive gate voltage of 55-75V to achieve the electroluminescence threshold. The thickness of the molybdenum disulfide nanolayer is preferably 8-20 nm, and the thickness of the tellurium nanolayer 11 is preferably 50-100 nm.

[0044] It should be noted that in semiconductor devices, a forward bias can facilitate the injection of electrons from one material (such as an n-type semiconductor) into another material (such as a p-type semiconductor). In this embodiment, a forward bias of 1.5V or higher ensures that electrons in the molybdenum disulfide nanolayer can cross the potential barrier and be effectively injected into the tellurium nanolayer 11.

[0045] In a field-effect transistor (FET), the gate voltage is used to control the concentration of charge carriers (electrons or holes) in the conductive channel. In this embodiment, a forward gate voltage of 55–75 V can be used to adjust the energy level arrangement between different materials. At the same time, the forward gate voltage allows the molybdenum disulfide nanolayer to accumulate enough electrons so that they can be injected into the tellurium nanolayer 11 when a forward bias voltage is applied.

[0046] In one exemplary embodiment, such as Figure 2 As shown, the heterolayer includes a thin graphene (Gr) nanolayer 21 and a thick graphene (Gr) nanolayer 22, which are at least partially stacked with the tellurium nanolayer 23. The thin graphene nanolayer 21 and the thick graphene nanolayer 22 are respectively disposed on the upper and lower surfaces of the tellurium nanolayer 23. The thin graphene nanolayer 21 and the thick graphene nanolayer 22 can inject holes and electrons into the tellurium nanolayer 23 under a forward bias voltage greater than 1.5V. The thin graphene nanolayer 21 is preferably a single layer or a double layer, the thickness of the thick graphene nanolayer 22 is preferably 5 to 10 layers, and the thickness of the tellurium nanolayer 23 is preferably 270-450 nm.

[0047] like Figure 3 As shown, one embodiment of the present invention provides an electroluminescent device, which includes a substrate layer 31 and a dielectric layer 32 stacked together. A tellurium nanolayer 33 and a heterostructure layer 34, which is heterogeneous to the tellurium nanolayer 33, are disposed on the dielectric layer 32. The tellurium nanolayer 33 is at least partially stacked on the upper surface of the heterostructure layer 34. The heterostructure layer 34 can inject electrons into the tellurium nanolayer 33 under a bias voltage. The injected electrons can recombine with holes in the tellurium nanolayer 33 to generate mid-infrared radiation with polarization characteristics.

[0048] Specifically, the tellurium nanolayer 33 is electrically connected to a positive electrode 35, and the heterolayer 34 is electrically connected to a negative electrode 36. The substrate layer 31 is preferably a silicon substrate, and the dielectric layer 32 is preferably a 285 nm thick silicon dioxide layer.

[0049] The present invention will be further described below with reference to specific embodiments.

[0050] Example 1

[0051] Tellurium nanosheets were prepared by chemical vapor deposition (CVD): TeO2 powder was sealed in a vacuum tube, and hydrogen gas was introduced at a flow rate of 40 sccm when the temperature was raised to 560°C. The temperature was then raised to 705°C and held for 10 minutes to reduce the TeO2 powder to tellurium nanosheets. The temperature was then lowered to room temperature.

[0052] Fabrication of a Te-MoS2 heterojunction electroluminescent device: First, a thin layer of MoS2 was transferred onto a silicon substrate with a 285 nm thick silicon dioxide (SiO2) layer using mechanical exfoliation to form a molybdenum disulfide nanolayer. Then, tellurium nanosheets were precisely transferred onto the molybdenum disulfide nanolayer using an optical fiber probe to construct a heterojunction. Electrodes were then fabricated on both the molybdenum disulfide nanolayer and the tellurium nanosheets using micro / nano fabrication techniques including spin-coating photoresist, electron beam lithography, development, and deposition, forming the Te-MoS2 heterojunction electroluminescent device. A schematic diagram of the electroluminescent device is shown below. Figure 4 As shown.

[0053] In the heterojunction structure of Example 1, the band structure of p-type Te and n-type MoS2 is a type I transposition band arrangement. The 285 nm thick SiO2 layer between the bottom silicon substrate and MoS2 can be used as a gate dielectric to adjust the electron concentration in MoS2.

[0054] Without an external bias or gate voltage, there is no current in the Te-MoS2 heterojunction, and no electrons are injected into Te. Figure 5 As shown, no electroluminescence signal will be generated at this time.

[0055] Under forward bias V ds >1.5V, positive gate voltage V gs Under conditions of ~60V, electrons are injected from MoS2 into Te, and recombine with holes in Te to produce linearly polarized mid-infrared radiation, such as... Figure 6 As shown. The mid-infrared electroluminescence signal of the Te-MoS2 heterojunction is as follows. Figure 7 As shown, the polarization electroluminescence pattern is as follows: Figure 8 As shown.

[0056] Example 2

[0057] Tellurium nanosheets were prepared by chemical vapor deposition (CVD): TeO2 powder was sealed in a vacuum tube, and hydrogen gas was introduced at a flow rate of 40 sccm when the temperature was raised to 560°C. The temperature was then raised to 705°C and held for 10 minutes to reduce the TeO2 powder to tellurium nanosheets. The temperature was then lowered to room temperature.

[0058] Fabrication of a Gr-Te-Gr heterojunction electroluminescent device: First, a five-layer bottom Gr nanolayer was transferred onto a silicon substrate with a 285 nm thick silicon dioxide (SiO2) layer using a mechanical exfoliation method to form a thick graphene nanolayer. Then, tellurium nanosheets were precisely transferred onto the thick graphene nanolayer using a fiber optic probe to construct a heterojunction. Next, a single-layer Gr nanolayer was transferred onto the top of the tellurium nanosheet using a dry transfer method to form a thin graphene nanolayer, thus constructing a Gr-Te-Gr vertical heterojunction structure. Electrodes were then fabricated on both the thick and thin graphene nanolayers using micro / nano fabrication techniques such as spin-coating photoresist, electron beam lithography, development, and deposition, forming the Gr-Te-Gr heterojunction electroluminescent device. A schematic diagram of the electroluminescent device is shown below. Figure 9 As shown.

[0059] In the heterojunction structure of Example 2, the Gr nanolayers at the bottom and top of Te inject electrons and holes into Te, respectively, under a forward bias voltage V. ds With an applied voltage of 1.5V, electrons and holes recombine in Te to generate mid-infrared radiation. The mid-infrared electroluminescence signal of the Gr-Te-Gr heterojunction is as follows: Figure 10 As shown, the polarization electroluminescence pattern is as follows: Figure 11 As shown.

[0060] Comparative Example 2

[0061] When a reverse bias and a negative gate voltage are applied to the Te-MoS2 heterojunction electroluminescent device prepared in Example 1, holes in Te tunnel into MoS2; at this time, there is no electron-hole recombination in Te, and no electroluminescent signal is generated. Figure 12 As shown.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An electroluminescent device having a tellurium-based heterojunction, characterized in that, The tellurium-based heterojunction includes a tellurium nanolayer and a heterostructure that is heterogeneous to the tellurium nanolayer, wherein the tellurium nanolayer and the heterostructure are at least partially stacked. The heterolayer includes a molybdenum disulfide nanolayer that is at least partially stacked with the tellurium nanolayer; or, the heterolayer includes a thin graphene nanolayer and a thick graphene nanolayer that are at least partially stacked with the tellurium nanolayer, wherein the thin graphene nanolayer and the thick graphene nanolayer are respectively disposed on the upper surface and the lower surface of the tellurium nanolayer. The heterolayer can inject electrons into the tellurium nanolayer under a bias voltage. The injected electrons can recombine with holes in the tellurium nanolayer to generate mid-infrared radiation.

2. The electroluminescent device according to claim 1, characterized in that, The molybdenum disulfide nanolayer can inject electrons into the tellurium nanolayer under a forward bias voltage greater than 1.5V and a positive gate voltage of 55~75V.

3. The electroluminescent device according to claim 1, characterized in that, The thickness of the molybdenum disulfide nanolayer is 8~20 nm, and the thickness of the tellurium nanolayer is 50~100 nm.

4. The electroluminescent device according to claim 1, characterized in that, The thin graphene nanolayer and the thick graphene nanolayer can inject holes and electrons into the tellurium nanolayer, respectively, under a forward bias voltage greater than 1.5V.

5. The electroluminescent device according to claim 1, characterized in that, The thin graphene nanolayer is a single layer or a double layer, the thick graphene nanolayer has 5 to 10 layers, and the thickness of the tellurium nanolayer is 270-450 nm.

6. The electroluminescent device according to claim 1, characterized in that, It includes a substrate layer and a dielectric layer stacked together, wherein the dielectric layer is provided with the tellurium nanolayer and the heterostructure layer, and the tellurium nanolayer is at least partially stacked on the upper surface of the heterostructure layer.

7. The electroluminescent device according to claim 6, characterized in that, The tellurium nanolayer is electrically connected to a positive electrode, and the heterolayer is electrically connected to a negative electrode.

8. The electroluminescent device according to claim 6, characterized in that, The substrate is a silicon substrate, and the dielectric layer is a 285nm thick silicon dioxide layer.

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