CN112047296B

CN112047296B - Method for realizing bidirectional atomic switch by thermal expansion of light-operated substrate

Info

Publication number: CN112047296B
Application number: CN202010983285.0A
Authority: CN
Inventors: 向东; 张素荣; 倪立发; 张伟强; 郭晨阳
Original assignee: Nankai University
Current assignee: Nankai University
Priority date: 2020-09-18
Filing date: 2020-09-18
Publication date: 2022-07-29
Anticipated expiration: 2040-09-18
Also published as: CN112047296A

Abstract

The optical control substrate thermal expansion realizes the atomic switch, which relates to the fields of molecular electronics, nano materials, chemistry and the like, and utilizes the external light to thermally expand the insulating glue on the substrate to drive the stretching and the compression of the electrodes at the two ends of the metal junction, thereby realizing the optical non-contact regulation and control of the electrical conductivity value of the metal junction, and realizing the bidirectional atomic switch by changing the light intensity and the illumination position and changing the change amplitude and the direction of the electrical conductivity value of the metal junction along with the change of the light intensity and the illumination position. The defect that the conventional atomic switch is difficult to integrate is overcome, the energy consumption in the implementation process is low, the noise is low, and the integrated application of a memory, a programmable switch and the like is facilitated.

Description

Method for realizing bidirectional atomic switch by thermal expansion of light-operated substrate

Technical Field

The invention is applied to the preparation of a bidirectional atomic-level switch, is particularly realized by utilizing laser, and relates to the fields of molecular electronics, nano materials, chemistry and the like.

Background

With the rapid development of the information age, the requirements for miniaturization and integration of electronic components are urgent, and the development of molecular electronics is rapid, wherein the switch components are concerned deeply. Compared with a molecular switch, the atomic switch (only an electrode and no molecules) is more stable, has higher repeatability, smaller size and lower energy consumption, and has more potential to be applied to memories, programmable switches and the like. Heretofore, there are various methods for implementing atomic switching, for example, using an electric field or an optical field to control the redox reaction of metal particles on the surfaces of electrodes at both ends, so as to promote the formation and fracture of a metal bridge at both ends of the electrodes, or using an external optical field to implement plasma heating, so as to implement atomic switching by thermal expansion of the electrodes at both ends.

The mechanical Controllable nano Junction (MCBJ) technology is mainly used for forming and researching the electrical characteristics of atoms and molecules, and the equipment has the advantages of good stability, simple device, easy operation and high repeatability.

The polyimide material has high insulating property, excellent mechanical property and high temperature resistance, and can be coated on a spring steel sheet as an insulating layer to form a substrate when a metal junction is prepared.

The invention utilizes the mechanical controllable nano-crack technology to prepare the atomic-level conductance value of the metal junction, and then utilizes the additional laser to control the thermal expansion of the substrate to realize the atomic switching of the metal junction, thereby realizing the static low-noise control of sub-Hermite-level precision, and realizing the bidirectional atomic-level switching by changing the laser irradiation position.

Disclosure of Invention

The invention provides a method for realizing bidirectional atomic switching by thermal expansion of a light-operated substrate, and the atomic-level switching regulation and control can be realized by laser without contacting a metal junction.

The experimental scheme adopted by the invention is as follows: a method for realizing atomic switch by using thermal expansion of a light-operated substrate comprises a He-Ne laser, a shutter, a polaroid, a converging lens, a substrate, a mechanical controllable splitting device, an XYZ three-dimensional translation stage and a semiconductor equipment analyzer. Wherein the substrate comprises the following components: and a gold wire with a nick in the middle is fixed on the spring steel sheet coated with a layer of polyimide insulating glue by two pieces of fixing black glue.

In the method for realizing the atomic switch by utilizing the thermal expansion of the light-operated substrate, the shutter is arranged at the light outlet of the He-Ne laser and then converts continuous light into periodic light; the two polaroids and the convergent lens are sequentially arranged in the direction of light path propagation, wherein the first polaroid and the second polaroid can integrally regulate the intensity of incident light, and the convergent lens converges and irradiates light on the substrate; the substrate is placed on the mechanical controllable nano-junction splitting device, the mechanical controllable nano-junction splitting device can stretch and compress the metal junction, and the metal junction is integrally placed below the convergent lens; the semiconductor device analyzer applies a bias voltage across the metal junction to measure its electrical signal.

According to the method for realizing the atomic switch by utilizing the thermal expansion of the light-operated substrate, the experimental principle is that laser irradiates on the substrate, the insulating glue generates thermal expansion and drives the two fixing black glues to move, and when the laser irradiates at different positions relative to the two fixing black glues of the metal junction, the moving directions and the sizes of the fixing black glues are different, so that the metal junction fixed on the insulating glue is stretched or compressed, and the bidirectional atomic switch effect is realized.

The invention has the technical advantages that: the method adopts the thermal expansion of the light-operated substrate to realize the atomic switch, can remotely control and control the on and off of the atomic junction in a non-contact way, and realizes the static low-noise regulation and control of the sub-angstrom level precision. In the experimental process, the use of the substrate material and the electrode material is diversified, the intensity of the external light and the bias voltage of two ends of the electrode are extremely small, and low energy consumption is realized. When the middle connection part of the atomic junction is cut or photoetched to be thin enough, the substrate does not need to be stretched by a mechanical controllable nano-junction cracking device, and the atomic-level switch regulation and control of the metal junction can be realized by utilizing laser, so that the later integration is facilitated. In addition, the method modulates the change amplitude and the change direction of the electric conductivity value of the atomic junction by changing the light intensity and the illumination position, so as to realize the bidirectional switch of the atomic junction.

Drawings

In order to make the object and technical solution of the present invention clearer, the present invention will be further described in detail with reference to the accompanying drawings:

fig. 1 is a schematic view of a photo-controlled atomic switch.

FIG. 2 is a schematic view of the area of a gold wire or parallel gold wires illuminated between two black glue pads on a substrate.

FIG. 3 shows that the conductivity of the metal junction decreases with light when the light is irradiated between two fixed black pastes on the substrate, on the gold wires or in the area parallel to the gold wires (FIG. 2), and "on" indicates that the light is on periodically.

FIG. 4 is a schematic view of the area of the gold wire or the parallel gold wires illuminated outside the two black glue regions on the substrate.

FIG. 5 shows that the conductivity of the metal junction increases with the light, and "on" indicates periodic light on, when the light is irradiated on the gold wires or in the area parallel to the gold wires (FIG. 4) outside the two fixed black pastes on the substrate.

In the figure: 1 is a laser, 2 is a shutter, 3 is a polaroid, 4 is a lens, 5 is incident light, 6 is a fixed end of a mechanical controllable nano-junction splitting device, 7 is fixed black glue, 8 is a metal junction, 9 is insulating glue, 10 is a spring steel sheet, 11 is a piezoelectric device of the mechanical controllable nano-junction splitting device, 12 is a circuit diagram of a semiconductor equipment analyzer, 13 is first black glue moving displacement, and 14 is second black glue moving distance.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

Example (b): coating a layer of insulating glue (polyimide, HD-4100, thickness of 50 mu m) (9) on a spring steel sheet (10), placing for 24h at room temperature, cutting a section of gold wire (length is about 150mm, diameter is 100 mu m, purity is 99.99%), circularly cutting the middle to form a suspended metal bridge (8), and fixing the cut metal junction on a substrate by using black glue (epoxy resin, STYCAST2850FT) (9) to form a substrate to be detected. The substrate is arranged on a mechanical controllable nano-split junction device and is fixed by two fixed ends (6), a bottom piezoelectric device (11) can move in the vertical direction, and fixed voltage 13mV (12) is applied to the two ends of a metal junction, so that the dynamic conductance values of the metal junction in the stretching and compressing processes can be measured. When the piezoelectric device is lifted off the substrate, the metal junction is slowly stretched until the conductance drops to about ten times G ₀ (G ₀ Is a monoatomic junction conductance value). A He-Ne laser (1) emits laser light having a wavelength of 633nm and an intensity of about 0.4mW, and is changed into periodic light by a shutter (2), two polarizing plates (3) adjust the intensity of the light, and a condensing lens (4) condenses and irradiates the incident light on a substrate.

When the converged incident light irradiates between the two fixed blackgels, in the area (figure 2) on or parallel to the gold wires, the displacement (13) of the first blackgel and the displacement (14) of the second blackgel are opposite in direction, so that the atomic junction is stretched, and the conductance value of the atomic junction is reduced along with the illumination (figure 3); when the converged incident light irradiates on the area outside the two fixed black glues (figure 4), the displacement (13) of the first black glue and the displacement (14) of the second black glue have the same direction and different sizes, and generate compression action on the atomic junctions, and the conductance value of the atomic junctions is reduced along with the irradiation of the light (figure 5).

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover equivalent methods within the spirit and scope of the appended claims.

Claims

1. A method for realizing bidirectional atomic switch by thermal expansion of a light-operated substrate is characterized by comprising the following steps: the method specifically comprises the following steps:

the method comprises the following steps: coating a layer of polyimide on a spring steel sheet, cutting a section of gold wire, performing circular cutting in the middle to form a suspended metal bridge, and fixing the cut gold atomic junction on a substrate by using black glue to form a substrate to be detected;

step two: placing the substrate on a mechanical controllable nano-split junction device, fixing the substrate by two fixed ends, applying fixed voltage to two ends of the gold atomic junction, and stretching the gold atomic junction until the electric conductivity value is reduced to ten times that of the monoatomic junction;

step three: the He-Ne laser emits laser, when incident light irradiates an area between two fixed black glues, the polyimide thermally expands under the light to drive the two fixed black glues of the gold atomic junction to move reversely to generate a stretching effect on the atomic junction, when the incident light irradiates an area outside the two fixed black glues, the two fixed black glues of the gold atomic junction are driven to move in the same direction, the displacement is different, a compression effect is generated on the atomic junction, and the bidirectional switch of the atomic junction is realized.

2. The method of claim 1 for thermally expanding a light management substrate to implement a bi-directional atomic switch, wherein: and the piezoelectric device of the mechanical controllable nano-junction splitting device moves up and down to obtain the atomic-level conductance value of the gold atomic junction.

3. The method of claim 1 for thermally expanding a light management substrate to implement a bi-directional atomic switch, wherein: the laser wavelength is 632.8nm, the light intensity is 0.4mW, the light intensity is controlled through two polaroids, and atomic switching can still be realized when the light intensity is reduced to 0.1 mW.

4. The method of claim 1 wherein the thermal expansion of the optically controlled substrate effects a bidirectional atomic switch, wherein: the intensity of incident laser is adjusted by utilizing the two polaroids, and the amplitude of change of the conductance value of the atomic junction is regulated and controlled.