Semi-metal device based on C5 (BN) 5 nanotube

Abstract

The invention discloses a semimetal device based on C5 (BN) 5 nanotubes, and belongs to the field of nano electronic devices, single electron spinning and semiconductors. Comprising a positive electrode, a negative electrode and a C5 (BN) 5 nanotube. In the invention, after non-spin polarized electrons pass through the C5 (BN) 5 nanotube-based semi-metal device, upward spin electrons can pass through the device, downward spin electrons are prevented from passing through the device, and the C5 (BN) 5 nanotubes enable the semi-metal device to have a spin filtering effect, so that a spin polarization effect exceeding about 80% can be achieved; the C5 (BN) 5 nanotube and the metal electrode are connected in an end-contact point connection mode, so that the semimetal device is stable in contact at high and low temperatures, the size of the device can be effectively shortened, and the size of the device is reduced by nearly 10 times compared with that of a traditional longitudinal connection device. Under the condition that the size is reduced, the contact resistance is not increased.

Description

Technical Field

[0001] The present invention belongs to the field of nanoelectronic devices, single electron spin and semiconductors, and more specifically, relates to a semi-metal device based on C5(BN)5 nanotubes. Background Art

[0002] In recent years, carbon nanotube technology has made rapid progress in materials, devices and circuits at home and abroad - achieving breakthroughs in carbon nanotube synthesis technology at the nanoscale, high-density and high-purity CNT arrays, CNT transistors with a gate length of 5nm (3nm technology node), and CNT three-dimensional integrated circuits. In particular, in 2020, Peking University's Peng Lianmou team used CNTs for the first time to realize large-scale carbon-based integrated circuits with performance exceeding that of silicon-based circuits. These achievements have laid a solid foundation for the practical development of CNT device and circuit technology and its large-scale integration.

[0003] However, unlike the metallic properties of pure carbon nanotubes, boron-nitrogen doped carbon nanotubes exhibit different electrical properties. Studies have shown that with the change of the boron-nitrogen doping ratio, boron-nitrogen carbon nanotubes exhibit four different properties: insulator, semiconductor, semimetal, and conductor. In terms of the connection between nanodevices and electrodes, the degree of recombination at the coupling end will affect the transmission of current, and it is necessary to find a thermally stable contact metal that can couple well with carbon nanotubes. Carbon nanotubes have been proven to be able to achieve device connection operations under high work function metal end contact.

[0004] When traditional chips process and store data, binary digital expression is achieved through voltage. When high voltage is input, it is 0, and when low voltage is input, it is 1. Data processing takes a long time, is slow, and cannot be performed simultaneously. However, quantum-level spin electronic devices use electron spin to achieve binary numbers. Spin-up is 0, and spin-down is 1. According to the superposition principle of quantum mechanics, quantum parallel computing can also be performed. It has the excellent characteristics of low power consumption, strong retention, and high integration at the nanometer level. At present, there are two main methods for generating spin currents: ferromagnetic electrodes contacting semiconductors to inject spin-polarized currents, and polarized light excites semiconductors to generate spin-polarized currents. However, the spin polarization rates generated by both methods are low, greatly affected by temperature, and have weak controllability. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of the present invention is to provide a semi-metallic device based on C5(BN)5 nanotubes, aiming to solve the problem that the spin polarization rate generated by the existing devices is relatively low and is greatly affected by temperature.

[0006] To achieve the above object, the present invention provides a semi-metal device based on C5(BN)5 nanotubes, the semi-metal device comprising:

[0007] Positive electrode, negative electrode and C5(BN)5 nanotubes;

[0008] The positive electrode and the negative electrode are metal electrodes, and are symmetrically arranged on both sides of the C5(BN)5 nanotube;

[0009] The cross section of the C5(BN)5 nanotube is an armchair shape, the axial direction of the C5(BN)5 nanotube is composed of 5 zigzag carbon chains and 5 zigzag boron nitrogen chains, and the end points of the C5(BN)5 nanotube are respectively connected to the contact points of the positive electrode and the negative electrode to serve as the central scattering area;

[0010] When the semi-metal device is working, non-spin polarized electrons are injected into the C5(BN)5 nanotubes through the positive electrode and the negative electrode, and the C5(BN)5 nanotubes only allow electrons with spin upward to pass through, thereby generating polarized current.

[0011] Preferably, the length of the semi-metallic device does not exceed 10 nm.

[0012] Preferably, the diameter of the C5(BN)5 nanotube is 0.7nm-0.9nm.

[0013] Preferably, the C5(BN)5 nanotubes are spontaneously formed at room temperature by two zigzag carbon nanoribbons and zigzag boron nitrogen nanoribbons with a width of 5 zigzag chains.

[0014] Preferably, the material of the metal electrode is Co-Mo alloy.

[0015] Preferably, the semi-metallic device further comprises:

[0016] The insulating substrate is located at the lower surface of the positive electrode, the negative electrode and the C5(BN)5 nanotubes.

[0017] Preferably, the insulating substrate has a double-layer structure, the upper layer is a SiO2 layer with a thickness of 20 nm, and the lower layer is a Si layer with a thickness of 10 nm.

[0018] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art:

[0019] The present invention provides a semi-metal device based on C5(BN)5 nanotubes, comprising: a positive electrode, a negative electrode and a C5(BN)5 nanotube. After non-spin polarized electrons pass through the semi-metal device based on C5(BN)5 nanotubes, electrons with spin-up can pass through the device, while electrons with spin-down are blocked from passing through. The C5(BN)5 nanotubes enable the semi-metal device to have a spin filtering effect, which can achieve a spin polarization effect of more than about 80%. The C5(BN)5 nanotubes and the metal electrodes are connected by end-contact points, so that the semi-metal device has stable contact at high and low temperatures, and can effectively shorten the size of the device, which is nearly 10 times smaller than the size of the traditional longitudinally connected device. When the size is reduced, the contact resistance does not increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a semi-metallic device based on C5(BN)5 nanotubes provided by the present invention.

[0021] Figure 2 This is a left view of the C5(BN)5 nanotube provided by the present invention.

[0022] Figure 3 This is an IV curve diagram of a semi-metal device provided in an embodiment of the present invention.

[0023] Figure 4 An energy band diagram of a semi-metal device provided by an embodiment of the present invention.

[0024] Figure 5 This is a transmission spectrum of a semi-metallic device provided in an embodiment of the present invention.

[0025] Figure 6 A spin polarization curve diagram of a semi-metal device under different voltages provided by an embodiment of the present invention.

[0026] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0027] 1- insulating substrate, 2- positive electrode, 3- C5(BN)5 nanotube, 4- negative electrode, 5- carbon atom, 6- boron atom, 7- nitrogen atom. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] like Figure 1As shown, the present invention provides a semi-metal device based on C5(BN)5 nanotubes, and the semi-metal device includes: a positive electrode, a negative electrode and C5(BN)5 nanotubes.

[0030] The positive electrode 2 and the negative electrode 4 are metal electrodes, and are symmetrically arranged on the left and right sides of the C5(BN)5 nanotube 3 .

[0031] Preferably, the material of the metal electrode is Co-Mo alloy.

[0032] The cross section of the C5(BN)5 nanotube 3 is an armchair shape. The axial direction of the C5(BN)5 nanotube is composed of 5 zigzag carbon chains and 5 zigzag boron nitrogen chains. The end points of the C5(BN)5 nanotube are respectively connected to the contact points of the positive electrode and the negative electrode to serve as the central scattering region. The function of the C5(BN)5 nanotube in the central scattering region is to generate polarized current and only allow current of a single spin to pass through.

[0033] like Figure 2 As shown, the C5(BN)5 nanotube 3 is a boron-nitrogen-carbon hybrid single-walled nanotube, that is, 5 of the 10 axial zigzag carbon atom chains in the armchair-type (5,5) carbon nanotube are doped and replaced by boron-nitrogen atom chains, wherein 5 represents a carbon atom, 6 represents a boron atom, and 7 represents a nitrogen atom.

[0034] Preferably, the diameter of the C5(BN)5 nanotube is 0.7nm-0.9nm.

[0035] Preferably, the C5(BN)5 nanotubes are spontaneously formed at room temperature by two zigzag carbon nanoribbons and zigzag boron nitrogen nanoribbons with a width of 5 zigzag chains.

[0036] Preferably, the length of the semi-metallic device does not exceed 10 nm.

[0037] Preferably, the semi-metallic device further comprises: an insulating substrate 1 located on the lower surface of the positive electrode 2 , the negative electrode 4 and the C5 (BN) 5 nanotubes 3 .

[0038] Preferably, the insulating substrate 1 is a double-layer structure, the upper layer is a SiO2 layer with a thickness of 20 nm, and the lower layer is a Si layer with a thickness of 10 nm. This structure can avoid oxidation.

[0039] When the semi-metal device is working, non-spin polarized electrons are injected into the C5(BN)5 nanotubes through the positive electrode and the negative electrode, and the C5(BN)5 nanotubes only allow electrons with spin upward to pass through, thereby generating polarized current.

[0040] Example

[0041] In this embodiment, the material of the metal electrode is Co-Mo alloy. Mo in Co-Mo alloy can catalytically reduce the connection temperature with the doped carbon tube, while Co can make the connection of the device effective at low temperature. Therefore, at high and low temperatures, the contact of the semi-metal device based on the boron nitrogen-carbon armchair type C5 (BN) 5 nanotube is relatively stable. The diameter of the C5 (BN) 5 nanotube is about 0.8nm, the device length is about 1.4nm, and the carrier mobility is 7.9×10 4 cm 2 / (V·s), and the thermal conductivity is about 6600W / (m·K).

[0042] like Figure 3 As shown in the figure, in the IV curve of spin-up, the current increases linearly with the increase of applied voltage, the through resistance is relatively stable and small, and more carriers pass through per unit time. In the IV curve of spin-down, before the applied voltage is 0.05V, the current value increases slowly with the increase of voltage. When the applied voltage is 0.05-0.20V, the curve is stable and almost unchanged, and the current value is around 0-1.5μA. After the applied voltage is 0.2V, the current value increases slowly, and the through resistance is large.

[0043] like Figure 4 As shown, in the spin-down sub-band diagram, the Fermi level is in the band gap, showing the characteristics of a semiconductor; while in the spin-up sub-band diagram, there are conduction electrons at the Fermi level, showing metallic properties, indicating that the device is a semi-metallic device with a spin filtering effect.

[0044] like Figure 5 As shown, in the spin-down transmission spectrum line, the transmittance is zero at the Fermi level, and in the spin-up transmission spectrum line, a large transmission peak appears at the Fermi level.

[0045] The calculation formula of spin polarization is as follows:

[0046] SFE(I)=(I ↑ -I ↓ ) / (I ↑ +I ↓ )

[0047] Among them, I ↑ and I ↓ denote the spin-up and spin-down currents, respectively.

[0048] According to calculation, the spin polarization rate of the semi-metal device based on C5(BN)5 nanotubes in the above embodiment is about 80%.

[0049] like Figure 6As shown in the figure, the spin polarization rate of the semi-metallic device based on C5(BN)5 nanotubes increases continuously with the increase of the applied voltage. When the applied voltage is low, the spin polarization rate increases rapidly. When the voltage is about 0.1V, the spin polarization rate increases at a slightly lower rate, and the curve shows an overall upward trend.

[0050] From the above analysis, it can be seen that the semi-metallic device based on C5(BN)5 nanotubes has a small and stable spin-up resistance, and a large spin-down resistance with a small current. The device can generate a high spin-polarized current, and spin-up electrons pass through, while spin-down electrons are retained. The device spin polarization rate is about 80%, which is simpler than generating spin current by polarized light excitation semiconductors and generating spin-polarized current by ferromagnetic electrode spin-polarized electron injection. The spin filtering effect and high spin polarization rate of the device itself can realize the control of binary 0 and 1 storage units to improve the data processing speed and quantity of computers, reduce heat dissipation risks, and ensure data non-volatility.

[0051] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A C-based 5 (BN) 5 Nanotube semi-metallic devices, It is characterized in that The semi-metallic device comprises: Positive electrode, negative electrode and C 5 (BN) 5 Nanotubes; The positive electrode and the negative electrode are metal electrodes, which are symmetrically arranged on C 5 (BN) 5 Both sides of the nanotube; The C 5 (BN) 5 The cross section of the nanotube is armchair shaped, C 5 (BN) 5 The axial direction of the nanotube is composed of 5 zigzag carbon chains and 5 zigzag boron-nitrogen chains. 5 (BN) 5 The endpoints of the nanotubes are connected to the contact points of the positive electrode and the negative electrode, respectively, to serve as the central scattering region; When the semi-metal device is working, non-spin polarized electrons are injected into C through the positive electrode and the negative electrode. 5 (BN) 5 Nanotubes, C 5 (BN) 5 The nanotubes allow only electrons with spin pointing upward to pass through, thus generating a polarized current.

2. The semi-metallic device according to claim 1, It is characterized in that The length of the semi-metal device does not exceed 10 nm.

3. The semi-metallic device according to claim 2, It is characterized in that The C 5 (BN) 5 The diameter of the nanotubes is 0.7nm-0.9nm.

4. The semi-metallic device according to claim 1, It is characterized in that The C 5 (BN) 5 The nanotubes were spontaneously formed at room temperature from two zigzag carbon nanoribbons and zigzag boron-nitrogen nanoribbons with a width of five zigzag chains.

5. The semi-metallic device according to claim 1, It is characterized in that The material of the metal electrode is Co-Mo alloy.

6. The semi-metallic device according to any one of claims 1 to 5, It is characterized in that The semi-metallic device further comprises: Insulating substrate, located between the positive electrode, negative electrode and C 5 (BN) 5 Bottom surface of nanotubes.

7. The semi-metallic device according to claim 6, It is characterized in that The insulating substrate has a double-layer structure, with the upper layer being SiO with a thickness of 20 nm. 2 layer, and the lower layer is a Si layer with a thickness of 10 nm.

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