阅读说明：本技术 基于二维碲烯/二维电子气异质结的二极管及其制备方法 (Diode based on two-dimensional telluriene/two-dimensional electron gas heterojunction and preparation method thereof ) 是由 姜昱丞 龚帅楠 高炬 于 2021-08-30 设计创作，主要内容包括：本发明涉及一种基于二维碲烯/二维电子气异质结的二极管及其制备方法,属于半导体技术领域。本发明将二维碲烯转移至钛酸锶衬底表面,再通过氩离子束轰击在钛酸锶衬底表面诱导出二维电子气,与二维碲烯接触形成范德华异质结。本发明所述的二维碲烯纳米线/二维电子气异质结、二维碲烯纳米片/二维电子气异质结的正向电流比反向电流分别高出10～(3)和10～(7)倍,两者均具有良好的二极管整流特性。本发明所述的二极管具有很高的稳定性,即便负向电压高达-100V,也无法将其击穿。这种异质结二极管结构简单、制备简单、性能优良,可广泛运用于电子芯片、智能器件等领域。(The invention relates to a diode based on a two-dimensional telluroene/two-dimensional electron gas heterojunction and a preparation method thereof, and belongs to the technical field of semiconductors. The method transfers two-dimensional tellurite to the surface of the strontium titanate substrate, and then induces two-dimensional electron gas on the surface of the strontium titanate substrate through argon ion beam bombardment, and the two-dimensional electron gas contacts with the two-dimensional tellurite to form Van der Waals heterojunction. The forward current of the two-dimensional tellurite alkene nanowire/two-dimensional electron gas heterojunction and the forward current of the two-dimensional tellurite alkene nanosheet/two-dimensional electron gas heterojunction are respectively 10 higher than the reverse current 3 And 10 7 And both have good diode rectification characteristics. The diode has high stability, and even if the negative voltage is as high as-100V, the diode cannot be broken down. The heterojunction diode has simple structure, simple preparation, excellent performance and good performanceThe method is widely applied to the fields of electronic chips, intelligent devices and the like.)

1. A diode based on two-dimensional telluriene/two-dimensional electron gas heterojunction, which is characterized in that: the two-dimensional heterojunction field effect transistor comprises a strontium titanate substrate, and a two-dimensional heterojunction and a metal electrode which are arranged on the strontium titanate substrate; the two-dimensional heterojunction is composed of two-dimensional tellurite and two-dimensional electron gas, the two-dimensional tellurite is arranged on the surface of the strontium titanate substrate, and the two-dimensional electron gas is obtained by bombarding the strontium titanate substrate by ion beams; the metal electrode partially covers the surface of the two-dimensional telluroene, the metal electrode is electrically conducted with the two-dimensional electron gas, and the metal electrode is not in contact with the two-dimensional electron gas.

2. The two-dimensional telluriene/two-dimensional electron gas heterojunction-based diode of claim 1, wherein: the two-dimensional telluriene is a two-dimensional telluriene nanowire and/or a two-dimensional telluriene nanosheet.

3. The two-dimensional telluriene/two-dimensional electron gas heterojunction-based diode of claim 2, wherein: when the two-dimensional tellurite is the two-dimensional tellurite nanowire, the working temperature range of the two-dimensional tellurite/two-dimensional electron gas heterojunction is 120-300K, and the forward current is 10 DEG higher than the reverse current respectively³And (4) doubling.

4. The two-dimensional telluriene/two-dimensional electron gas heterojunction-based diode of claim 2, wherein: when the two-dimensional telluriene is a two-dimensional telluriene nanosheet, the working temperature range of the two-dimensional telluriene/two-dimensional electron gas heterojunction is 10-300K, and the forward current is 10 higher than the reverse current respectively⁷And (4) doubling.

5. The two-dimensional telluriene/two-dimensional electron gas heterojunction-based diode of claim 1, wherein: the metal electrode is one or more of gold, silver, aluminum and copper.

6. The method for preparing a diode based on a two-dimensional tellurine/two-dimensional electron gas heterojunction as claimed in any of claims 1 to 5, comprising the steps of:

s1, transferring the two-dimensional tellurite to the surface of the strontium titanate substrate, and heating to obtain a sample A;

s2, partially covering the photoresist on the two-dimensional tellurine on the surface of the sample A and the strontium titanate substrate on the same side in the step S1, and exposing the rest part on the other side to obtain a sample B;

s3, depositing a metal material on the surface of the sample B in the step S2 by utilizing a magnetron sputtering technology under the argon pressure to form a metal electrode, and removing the photoresist to obtain a sample C;

s4, partially covering the photoresist on the two-dimensional tellurine on one side of the metal electrode and the strontium titanate substrate on the same side of the sample C in the step S3 to obtain a sample D;

and S5, bombarding the sample D obtained in the step S4 by using an argon ion beam under the argon pressure, and forming two-dimensional electron gas on the upper surface of the strontium titanate substrate and on one side far away from the metal electrode to obtain the diode based on the two-dimensional telluridene/two-dimensional electron gas heterojunction.

7. The method of claim 6, wherein the two-dimensional tellurine/two-dimensional electron gas heterojunction-based diode comprises: in the step S1, the heating is carried out for 1-2h at 50-80 ℃.

8. The method of claim 6, wherein the two-dimensional tellurine/two-dimensional electron gas heterojunction-based diode comprises: in step S3, the argon gas pressure is 2 × 10^-4-6×10^-4mbar; the temperature of the magnetron sputtering is 80-100 ℃.

9. The base of claim 6The preparation method of the diode in the two-dimensional tellurine/two-dimensional electron gas heterojunction is characterized by comprising the following steps of: in step S5, the argon gas pressure is 3 × 10^-6-8×10^-6mbar。

10. The method of claim 6, wherein the two-dimensional tellurine/two-dimensional electron gas heterojunction-based diode comprises: in step S5, the bombarding voltage is 200-400V; the bombardment time is 10-15 min.

Technical Field

The invention relates to the technical field of semiconductors, in particular to a diode based on a two-dimensional tellurine/two-dimensional electron gas heterojunction and a preparation method thereof.

Background

Among the semiconductor devices, the diode is the simplest device, but one of the most common basic electronic components in power electronic circuits, and plays a light role in the circuit. With the continuous progress of the switching devices, the switching speed is continuously increased, and the requirements on the performance of the diode are higher and higher, so that a new diode is needed to realize the improvement of the reverse voltage and the expansion of the working temperature range. Since the two-dimensional telluroene (2D-Te) is successfully prepared in 2017, the two-dimensional telluroene has great potential in the application of electronic devices such as photoelectric detectors, field effect transistors and the like due to the excellent characteristics of thickness-dependent band gap, environmental stability, piezoelectric effect, high carrier mobility, photoresponse and the like. Two-dimensional electron gas has attracted much attention in recent years because of its physical properties such as superconductivity, magnetic resistance, and ferromagnetism. Devices manufactured by similar structures in the prior art have poor rectification performance at normal temperature, the ratio of positive current to negative current is small, and the negative current has a leakage condition. Many devices with similar structures lose rectification characteristics at low temperature, and cannot work in special environments.

Disclosure of Invention

In order to solve the technical problems, the invention provides a diode based on a two-dimensional telluriene/two-dimensional electron gas heterojunction and a preparation method thereof. The invention aims to provide a high-performance diode based on a 2D-Te/2DEG van der Waals heterojunction, which is formed by constructing van der Waals heterojunctions of two-dimensional telluriene (2D-Te) and two-dimensional electron gas (2DEG) in different forms, and utilizing the excellent rectification characteristics and the different temperature dependence of resistance.

The invention provides a diode based on a two-dimensional tellurine/two-dimensional electron gas heterojunction, which comprises a strontium titanate substrate, and a two-dimensional heterojunction and a metal electrode which are arranged on the strontium titanate substrate; the two-dimensional heterojunction is composed of two-dimensional tellurite and two-dimensional electron gas, the two-dimensional tellurite is arranged on the surface of the strontium titanate substrate, and the two-dimensional electron gas is obtained by bombarding the strontium titanate substrate by ion beams; the metal electrode partially covers the surface of the two-dimensional telluroene, the metal electrode is electrically conducted with the two-dimensional electron gas, and the metal electrode is not in contact with the two-dimensional electron gas.

Further, the two-dimensional telluriene is a two-dimensional telluriene nanowire and/or a two-dimensional telluriene nanosheet.

Further, when the two-dimensional tellurite is a two-dimensional tellurite nanowire, the operating temperature range of the two-dimensional tellurite/two-dimensional electron gas heterojunction is 120-300K, and the forward current is 10 higher than the reverse current respectively³And (4) doubling.

Further, when the two-dimensional telluriene is a two-dimensional telluriene nanosheet, the working temperature range of the two-dimensional telluriene/two-dimensional electron gas heterojunction is 10-300K, and the forward current is 10 higher than the reverse current respectively⁷And (4) doubling.

Further, the metal electrode is one or more of gold, silver, aluminum, and copper.

Further, the thickness of the two-dimensional telluriene is 20-80 nm; the thickness of the two-dimensional telluriene nanowire is 20-40 nm; the thickness of the two-dimensional telluriene nanosheet is 20-80 nm.

Further, the thickness of the metal electrode is 80-120 nm.

Further, the thickness of the two-dimensional electron gas is 80-120 nm.

The second purpose of the invention is to provide a preparation method of a diode based on a two-dimensional tellurine/two-dimensional electron gas heterojunction, which comprises the following steps:

s1, transferring the two-dimensional tellurite to the surface of the strontium titanate substrate, and heating to obtain a sample A;

s2, partially covering the photoresist on the two-dimensional tellurine on the surface of the sample A and the strontium titanate substrate on the same side in the step S1, and exposing the rest part on the other side to obtain a sample B;

s3, depositing a metal material on the surface of the sample B in the step S2 by utilizing a magnetron sputtering technology under the argon pressure to form a metal electrode, and removing the photoresist to obtain a sample C;

s4, partially covering the photoresist on the two-dimensional tellurine on one side of the metal electrode and the strontium titanate substrate on the same side of the sample C in the step S3 to obtain a sample D;

and S5, bombarding the sample D obtained in the step S4 by using an argon ion beam under the argon pressure, and forming two-dimensional electron gas on the upper surface of the strontium titanate substrate and on one side far away from the metal electrode to obtain the diode based on the two-dimensional telluridene/two-dimensional electron gas heterojunction.

Further, in the step of S1, the heating is performed for 1-2h at 50-80 ℃.

Further, in the step of S3, the argon gas pressure is 2 × 10^-4-6×10^-4mbar. The argon gas has large molecular weight, so that better sputtering efficiency is ensured, the helium gas and the neon gas have small molecular weight and general sputtering efficiency, meanwhile, inert gases with too large molecular weight such as krypton gas and xenon gas need larger ionization energy, the cost is higher, the argon gas is relatively easier to prepare, and the price is lower.

Further, in the step S3, the temperature of the magnetron sputtering is 80 to 100 ℃. Magnetron sputtering includes DC sputtering and RF sputtering; the DC sputtering power is 140-160W, and the sputtering time is 3-5 min; the RF sputtering power is 150-170W, and the sputtering time is 1-4 min.

Further, in the step of S5, the argon gas pressure is 3 × 10^-6-8×10^-6mbar。

Further, in step S5, the bombarding voltage is 200-; the bombardment time is 10-15 min.

Further, the two-dimensional telluriene is prepared by the following steps:

adding sodium tellurite and polyvinylpyrrolidone (PVP) into water, stirring, adding ammonia water and hydrazine hydrate, mixing, and heating to obtain the two-dimensional telluroene.

Further, the volume ratio of the ammonia water to the hydrazine hydrate is 1.8-2.2: 1.

further, the mass-volume ratio of the sodium tellurite to the hydrazine hydrate is 50-60: 1g/L

Further, the heating is carried out for 15-25h at the temperature of 160-200 ℃.

The working principle of a diode based on a two-dimensional tellurine/two-dimensional electron gas heterojunction is as follows:

2D-Te is a p-type material and 2DEG is an n-type material. A p-n junction will be formed between them. When a positive voltage is applied to the p-n junction, the barrier height is reduced and the device conducts. When a negative voltage is applied, the barrier height increases greatly, impeding the transport of carriers, resulting in the isolation of the device at negative voltages.

The electrical transport properties of two-dimensional telluridines/two-dimensional electron gases are affected by edge effects. The edge effect is caused by the distortion of the crystal lattice at the edge due to the weakened forces of other atoms to which the atoms at the edge are subjected. When electrons are transported at the edges, the lattice disorder due to lattice distortion is high, causing the current to follow the conduction law of the non-metal. Thus, as the temperature decreases, the current at the edge decreases. In this case, the internal current will increase, still following metallic conduction, i.e. the internal current increases with decreasing temperature. For two-dimensional telluriene nanowires, edge effects dominate in the electrical transport because the edge effect area accounts for a large proportion of the total area. The measured current is the sum of the edge current and the internal current. As the temperature decreases, the decrease in the edge current is greater than the increase in the internal current, resulting in an overall decrease in the measured current. In contrast, the edge effect has less effect on the two-dimensional telluriene nanosheets than on the two-dimensional telluriene nanowires. Under a larger positive bias voltage, the two-dimensional telluriene nanosheet/two-dimensional electron gas (TNS/2DEG) shows typical metal conducting characteristics.

Compared with the prior art, the technical scheme of the invention has the following advantages:

(1) the diode of the invention has excellent rectification characteristic, and the forward current is 10 higher than the reverse current⁷Twice, its negative direction is nearly insulating. After the TNS/2DEG heterojunction is placed for two months, the rectification characteristic is not obviously attenuated, and the TNS/2DEG heterojunction cannot be broken down when the negative voltage reaches-100V.

(2) The diode can work in the full temperature range, the TNW/2DEG heterojunction can still maintain the rectification characteristic when being 120K, the 3V current of the TNS/2DEG heterojunction is higher than that of the TNS/2DEG heterojunction when being 10K, and the rectification performance is better.

(3) The diode based on the 2D-Te/2DEG heterojunction is almost the best of the Van der Waals heterojunction so far, and is a novel high-performance and all-temperature diode of a mixed Van der Waals heterojunction. The diode has simple structure, simple preparation and excellent performance, and can be widely applied to the fields of electronic chips, intelligent devices and the like.

Drawings

In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the present disclosure taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic structural diagram of a heterojunction provided by an embodiment of the invention; wherein 1 is strontium titanate substrate, 2 is two-dimensional telluroene, 3 is metal electrode, 4 is two-dimensional electron gas, 5 wire.

FIG. 2 is a graph of current-voltage curves at 300K for the diode provided in test example 1 of the present invention; wherein a is a current-voltage curve of the TNW/2DEG heterojunction at 300K, and b is a current-voltage curve of the TNS/2DEG heterojunction at 300K.

FIG. 3 is a graph of junction resistance versus temperature at various voltages as provided in test example 2 of the present invention; wherein a is a junction resistance-temperature curve diagram of the TNW/2DEG heterojunction under different voltages, and b is a junction resistance-temperature curve diagram of the TNS/2DEG heterojunction under different voltages.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

Examples

Referring to fig. 1, the 2D-Te/2DEG heterojunction of the embodiment of the invention is schematically shown in structure, and the diode includes a strontium titanate substrate 1, and a two-dimensional heterojunction and a metal electrode 3 disposed on the strontium titanate substrate 1; the two-dimensional heterojunction is composed of two-dimensional tellurine 2 and two-dimensional electron gas 4, the two-dimensional tellurine 2 is arranged on the surface of the strontium titanate substrate 1, and the two-dimensional electron gas 4 is obtained by bombarding the strontium titanate substrate 1 by ion beams; the metal electrode 3 partially covers the surface of the two-dimensional telluroene 2, the metal electrode 3 is electrically conducted with the two-dimensional electron gas 4 through a lead 5, and the metal electrode 3 is not in contact with the two-dimensional electron gas 4.

The diode based on the two-dimensional telluriene/two-dimensional electron gas heterojunction and the preparation method thereof are divided into two parts, namely growth of two-dimensional telluriene by a hydrothermal method and preparation of the diode.

A. Growth of two-dimensional telluroene by hydrothermal method

(1) 16ml of double distilled water was prepared, and 46mg of sodium tellurite (Na) was added thereto₂TeO₃) Uniformly stirring with a proper amount of polyvinylpyrrolidone (PVP);

(2) stirring for 20min by a magnetic stirrer;

(3) transferring to a tetrafluoro lining of the hydrothermal kettle, adding 1.66ml of ammonia water solution and 0.84ml of hydrazine hydrate, and sealing the hydrothermal kettle;

(4) placing in an oven, and keeping the temperature at 160 ℃ for 20 h;

(5) naturally cooling to room temperature after heat preservation is finished, centrifuging the obtained dark blue solution at 4000r/min for 15min, finding silvery white precipitate at the bottom of a centrifugal tube, and then continuously centrifuging and washing for 3 times by using distilled water to finally obtain a 2D-Te suspension.

B. Preparation of diodes

(1) Taking out 2D-Te from the suspension by taking Strontium Titanate (STO) as a substrate, and heating for 1h in a glove box at 70 ℃ to ensure that the 2D-Te is in closer contact with the surface of the STO;

(2) covering the 2D-Te substrate with the area of 2/3 on one side and the STO substrate on the same side with photoresist by adopting a photoetching technology, and exposing the rest part;

(3) at 3X 10^-4Depositing gold on the surface of the sample obtained in the step (2) by utilizing a magnetron sputtering technology under the mbar argon gas pressure; removing the photoresist to prepare a gold electrode;

(4) covering photoresist on the area of 2/3 side with gold electrode and the STO substrate on the same side by using photoetching technology;

(5) at 5X 10^-6Under mbar argon gas pressure, using 300V Ar⁺Bombarding the surface of the sample obtained in the step (4) for 12min by using an argon ion beam to form two-dimensional electron gas; and cleaning, and electrically conducting the metal electrode and the two-dimensional electron gas through a lead to obtain the diode based on the two-dimensional telluriene/two-dimensional electron gas heterojunction.

This example prepares a 2D-Te/2DEG heterojunction on an STO substrate. The single crystal STO substrate is a transparent insulating oxide, and conductive two-dimensional electron gas is formed on the surface of the substrate after ion beam bombardment, wherein the single crystal STO substrate is an N-type conductor; the 2D-Te is a P-type conductive two-dimensional layered semiconductor material. Since the size of the 2D-Te is only micron-sized, the embodiment increases the conductive area by evaporating the gold electrode at one end of the 2D-Te through the photoetching technology.

Test example 1

Referring to fig. 2, which is a current-voltage curve at 300K for the present embodiment, and fig. 2a is a current-voltage curve at 300K for the TNW/2DEG heterojunction, the forward current is 3 orders of magnitude higher than the reverse current at 3V. FIG. 2b is a current-voltage graph of the TNS/2DEG heterojunction at 300K, with a ratio of positive to negative current up to 7 orders of magnitude at 3V. The TNS/2DEG heterojunction was prepared one month after I-V measurements and had little or no degradation in performance. Even if negative voltage is applied up to-100V, the heterojunction still cannot be broken down, and the negative leakage current is less than 2 nA. The positive-negative current ratio is still as high as almost 5 orders of magnitude, which means excellent rectification and can therefore be applied to diodes.

Test example 2

Referring to fig. 3, which is a graph of junction resistance versus temperature at different voltages according to an embodiment of the present invention, fig. 3a is a graph of junction resistance versus temperature at different voltages for a tellurium TNW/2DEG heterojunction, which has a resistance that monotonically increases with decreasing temperature, and which tends to be insulating at about 120K with decreasing temperature at 3V. FIG. 3b is a graph of junction resistance versus temperature for a TNS/2DEG heterojunction at different voltages, which maintains excellent rectifying characteristics over the full temperature range of 10K-300K, with junction resistance decreasing with increasing temperature when the voltage is less than 2.2V and junction resistance increasing with increasing temperature when the voltage is greater than 2.2V, exhibiting different properties from TNW/2DEG heterojunction.

The high-performance diode based on the 2D-Te/2DEG Van der Waals heterojunction has excellent rectification characteristic and can normally work in a wide temperature range. The embodiment of the invention has the advantages of low manufacturing cost, good performance and strong stability, and has application prospect in the fields of electronic chips, intelligent devices and the like.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.