A Negative Differential Resistance Diode Based on Cold Metal

Abstract

The present invention relates to a negative differential resistance diode, and in particular to a negative differential resistance diode based on cold metal, comprising a substrate and electrodes arranged on the substrate, wherein a van der Waals heterojunction made of cold metal is arranged between the electrodes. Therefore, the present invention has the following advantages: 1. The present invention is different from the existing NDR device based on semiconductor materials, but adopts a heterojunction based on "cold" metal materials. Due to its metallicity and unique energy band structure, it successfully realizes a very large peak current, which is several orders of magnitude higher than that of the existing tunnel diode. 2. The "cold" metal heterojunction NDR device of the present invention can simultaneously generate a very large current peak-to-valley ratio and peak current. On the one hand, a larger current peak-to-valley ratio and peak current can improve the noise tolerance of the device. On the other hand, a higher peak current increases the output power of the NDR device, thereby improving the stability of the negative resistance oscillator.

Description

Technical Field

[0001] The invention relates to a negative differential resistance diode, in particular to a negative differential resistance diode based on cold metal. Background Art

[0002] Existing NDR devices, such as tunnel diodes and resonant tunnel diodes, are all turned on by electron tunneling, so the peak current generated is very small. It is difficult to maintain the stability of the oscillation circuit when applied to it. In addition, the small peak current and current peak-to-valley ratio also limit the noise tolerance of the NDR device. When the noise is large, the negative resistance effect of the NDR device is difficult to maintain. Summary of the invention

[0003] The present invention mainly solves the technical problems existing in the prior art and provides a "cold" metal heterojunction NDR device constructed by using a "cold" metal material with a band gap near the Fermi level. The metallic property of the "cold" metal heterojunction not only enables it to generate a very large peak current, but also its unique energy band structure ensures that it can achieve a large current peak-to-valley ratio.

[0004] The present invention adopts a "cold" metal heterojunction NDR device to address the defects of low peak current and output power of tunnel diodes. The metallic property of the "cold" metal heterojunction ensures that it can generate a very large peak current. In a negative resistance oscillator, a larger peak current enables the "cold" metal diode to provide a larger output power, thereby ensuring that the oscillation circuit starts and continues to oscillate. In addition, when there is noise in the circuit, a larger peak current also has a higher noise tolerance, thereby maintaining the negative resistance characteristics of the device.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions:

[0006] A cold metal-based negative differential resistance diode, characterized in that it comprises a substrate and electrodes arranged on the substrate, wherein a van der Waals heterojunction made of a cold metal material is arranged between the electrodes.

[0007] In the above-mentioned cold metal-based negative differential resistance diode, the van der Waals heterojunction includes an A layer and a B layer above the A layer, wherein the A layer is in a U-shape and the B layer is in a Z-shape.

[0008] In the above-mentioned cold metal-based negative differential resistance diode, the A layer is a single material, using NbS 2 or TaS 2 Any one of .

[0009] In the above-mentioned cold metal-based negative differential resistance diode, the B layer is a single material, using NbSe 2 , or TaSe 2Any one of .

[0010] In the above-mentioned cold metal-based negative differential resistance diode, the electrode is a copper electrode.

[0011] In the above-mentioned cold metal-based negative differential resistance diode, the substrate is SiO 2 Material substrate.

[0012] Therefore, the present invention has the following advantages: 1. The present invention is different from the existing NDR device based on semiconductor materials. Instead, it adopts a heterojunction based on "cold" metal materials. Due to its metallicity and unique band structure, it successfully achieves a very large peak current, which is several orders of magnitude higher than the existing tunnel diode. 2. The "cold" metal heterojunction NDR device of the present invention can simultaneously generate a very large current peak-to-valley ratio and peak current. On the one hand, a larger current peak-to-valley ratio and peak current can improve the noise tolerance of the device. On the other hand, a higher peak current increases the output power of the NDR device, thereby improving the stability of the negative resistance oscillator. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attached Figure 1 It is a schematic diagram of the present invention.

[0014] Attached Figure 2a This is a typical current-voltage curve of a negative differential resistance device.

[0015] Attached Figure 2b is the bias voltage V b =V 0 Band alignment diagram of A / B heterojunction when .

[0016] Attached Figure 2c is the bias voltage V b =V 1 Band alignment diagram of A / B heterojunction when .

[0017] Attached Figure 2d is the bias voltage V b =V 2 Band alignment diagram of A / B heterojunction when .

[0018] Attached Figure 2e is the bias voltage V b =V 3 Band alignment diagram of A / B heterojunction when .

[0019] (a) Schematic diagram of IV characteristics of A / B heterojunction NDR device. (b) Different bias voltages (V b ) energy band diagram, where V b The corresponding V 0 To V 3, as shown in (a). p and E n are the Fermi levels of A and B, respectively. The A and B boxes in (be) correspond to the band gaps of materials A and B, the size of the black arrow indicates the current size under the bias voltage, and the dotted line and the corresponding E p and E n Represents the Fermi level of materials A and B respectively. The gray area under the dotted line indicates that the energy levels below the Fermi level are completely filled with electrons. The solid spheres represent electrons and the hollow spheres represent holes. The number of carriers represents the change in carrier concentration under different bias voltages. The carriers in the blue and white backgrounds represent electron transport and hole transport, respectively. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0021] Example:

[0022] The "cold" metal used in the present invention is different from ordinary metal materials with continuous state density. It has a conduction band gap (E CG ) or below the Fermi level valence band gap (E VG ). Therefore, a type III band-aligned NDR device can be realized by constructing a “cold” metal heterojunction A / B by using “cold” metal materials A and B. A is made of NbS 2 or TaS 2 Any one of the above, B is NbSe 2 , or TaSe 2 Any of the following; construct a "cold" metal heterojunction diode by chemical vapor deposition or mechanical lift-off.

[0023] like Figure 1 As shown in the figure, 1 is the power supply, 2 is the A layer, 3 is the B layer, and 4 is the electrode. Taking the A / B heterojunction NDR device as an example, the curves of the device under different bias voltages (V b ) under the IV curve and energy band diagram. In Figure 2, the IV curve in (a) shows the typical N-shaped characteristics of NDR devices. In the case of no bias voltage in (b), the current value is zero. When reaching the peak point V 1 Before, the E on the n side (“cold” metal B) VG Lower than E on the p-side (“cold” metal A) CG In (c), as V b The increase of E on the p side p Gradually approaching E on the n side VG With E n and E p The transmission path between them reaches its widest point, and the device current reaches its peak point V 1When V b Continue to increase and reach the valley point V 2 When E on the p side in (d) CG Move down and connect with E on the n side VG overlap, thus cutting off the electron transmission path, so the device current decreases. b Further increase to (e) V 3 When E on the p side CG and E p The hole transmission path between the two electrodes is opened, causing the IV curve to rise again. The A / B heterojunction in the present invention successfully achieves a very large peak current due to its metallicity and unique energy band structure, and the current value is several orders of magnitude higher than that of the existing tunnel diode.

[0024] The present invention is different from the existing heavily doped tunnel diode or III-type band-aligned semiconductor heterojunction NDR device. The present invention uses a "cold" metal with a band gap near the Fermi level to construct a "cold" metal heterojunction NDR device. Due to the metallic properties of the "cold" metal heterojunction, it can not only generate a very large peak current, but also its unique band structure ensures that it can achieve a large current peak-to-valley ratio.

[0025] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A cold metal based negative differential resistance diode, characterized in that: It includes a substrate and electrodes arranged on the substrate, wherein the PN junction between the electrodes is a van der Waals heterojunction made of cold metal material; The van der Waals heterojunction includes a layer A and a layer B above the layer A; The A layer is any one of NbS2 or TaS2; The B layer is any one of NbSe2 or TaSe2.

2. A cold metal based negative differential resistance diode according to claim 1, characterized in that: The A layer is in a U shape, and the B layer is in a Z shape.

3. A cold metal based negative differential resistance diode according to claim 1, characterized in that: The electrode is a copper electrode.

4. A cold metal based negative differential resistance diode according to claim 1, characterized in that: The substrate is a SiO2 substrate.

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