CN115980131B

CN115980131B - Flexible material-based planar mechanical controllable cracking method

Info

Publication number: CN115980131B
Application number: CN202211311292.1A
Authority: CN
Inventors: 赵雪妍; 向东; 谭敏; 张素荣; 张旭斌; 许晓娜
Original assignee: Nankai University
Current assignee: Nankai University
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2023-08-01
Anticipated expiration: 2042-10-25
Also published as: CN115980131A

Abstract

Based on the chip made of the flexible film material, the flexible substrate is stretched in the horizontal direction by utilizing the mechanical force in the vertical direction generated by the piezoelectric ceramic in a mode of combining the sliding rail and the piezoelectric ceramic, and the microstructure on the substrate is driven to stretch or shrink, so that the formation and fracture of a metal junction constructed in the horizontal direction are realized.

Description

Flexible material-based planar mechanical controllable cracking method

Technical Field

The invention is applied to a mechanical controllable cracking technical device, in particular to a device based on flexible materials, and relates to the fields of molecular electronics, flexible materials, optics and the like.

Background

The semiconductor silicon-based device has been widely used in various fields, and in 1965, the size of an electronic component is exponentially reduced with time, and when the conventional silicon-based semiconductor device cannot meet the requirement of continuously reducing the size, molecular electronics has been developed, and the functions of the electronic device are realized by utilizing the properties of atoms, molecules or clusters of molecules. More importantly, as the molecular device is often in the scale range smaller than 10nm, the transportation property is more obviously affected by various quantum effects, thus showing a plurality of working principles and device performances different from the traditional device and further promoting the development of molecular electronics. The functional photoelectronic device constructed by single molecule can meet the requirements of microminiaturization and even high integration of the device, can study the intrinsic physicochemical phenomenon of the material at the molecular level and the regulation and control rule thereof, and is a scientific foundation for the research and development of future molecular photoelectronic devices. The realization of the field effect transistor enables the development of molecular electronics to advance rapidly, and simultaneously, a single-molecule junction technology is also developed rapidly, so that means are more diversified, wherein the technology of mechanically controllable cracking (Mechanically Controllable Break Junction, MCBJ) and a scanning tunneling microscope cracking (Scanning Tunneling Microscope Break Junction, STM-BJ) method are widely applied.

STM utilizes the ductility of noble metals to prepare electrode-molecule-electrode junctions by stretching and shrinking in the vertical direction. The research on the photoelectric characteristics of the molecular device is limited, and although the molecular device can be modified on the basis of STM, for example, an optical path is built on an optical platform, and light is irradiated on a substrate electrode, the mode of the externally-applied optical field is complex, and the optical path is not suitable to move after being fixed, so that the follow-up operation is not facilitated. For the mechanically controllable nano-cleavage technology, the device consists of a flexible substrate and a gold wire with a notch, and when the substrate is bent upwards, the electrode is formed by precisely controlling the breakage of the metal wire through a piezoelectric element. Although the stability is higher, the light spots are difficult to focus when moving in the vertical direction under the influence of the splitting mode, and the research on the photoelectric property of molecules is limited. Based on this, it is very important to propose a simple, highly reproducible planar cleavage technique that can achieve single molecule measurements at room temperature.

TPU (Thermoplastic polyurethanes) thermoplastic polyurethane elastomer rubber has excellent high-tension, tough and ageing-resistant properties, and is widely applied to various aspects such as electronics, medical treatment, sports and the like at present, and has incomparable high-strength and ageing-resistant properties compared with other elastic materials. A TPU flexible material of a specific thickness can be used as a substrate instead of a spring steel sheet, on which a metal electrode is prepared.

According to the invention, the TPU flexible material is used as a substrate, and the TPU flexible film is stretched by using the tensile force generated by the piezoelectric ceramic to drive the metal wire to move, so that the planar metal atomic-level fracture process is realized. And when an optical field is externally applied, the problem of focal length change in the traditional splitting technology can be avoided, and a new technical means is provided for the research of single-molecule photoelectric effect.

Disclosure of Invention

The invention aims to provide a method for realizing controllable cracking in the horizontal direction by taking a flexible material as a substrate and utilizing piezoelectric ceramics to drive a flexible film to stretch based on the limitation brought by researching single-molecule photoelectric effect in the existing cracking technology.

The invention comprises a baseplate with holes, a TPU flexible chip, piezoelectric ceramics, a straight guide rail, a slide bar and a current equipment analyzer. The TPU flexible chip comprises the following components: and a gold thread with a suspension groove at the middle part is fixed on the TPU flexible film through a black glue.

The method comprises the following specific steps of: the flexible chip is arranged on the substrate with the holes, and is fixed in a three-section fixing mode, namely two ends fixed on the substrate and one end connected with the sliding rod. One end of the chip fixed on the substrate is tightly fixed on the substrate through the brass pressing sheet, and the other end of the chip is also fixed on the substrate through the brass pressing sheet, but is not completely fixed, so that a certain gap is reserved between the chip and the substrate, the purpose of the method is that the part with gold wires can be in tight contact with the substrate as much as possible, and the brass sheet which is not completely pressed and fixed provides possibility for stretching the flexible film, and the direction of horizontal stretching is fixed; connecting the rest flexible film with a slide bar of the straight guide rail, wherein the tail end of the slide bar is arranged on a push rod of the piezoelectric ceramic, the push rod at the top of the piezoelectric ceramic just can penetrate out of a hole of the base plate, and the piezoelectric ceramic can drive the slide bar to move when being displaced, so that the flexible substrate can be stretched, and finally, the stretching and the shrinking of the metal structure in the horizontal direction are realized; the metal wire on the chip is connected with an external current equipment analyzer through two leads, controls the movement of the piezoelectric ceramics and measures the electrical signals of the piezoelectric ceramics.

The invention has the technical advantages that: the flexible chip is manufactured in a very simple mode, the precise control of the electrode gap is realized through the combination of the guide rail and the piezoelectric ceramic, and the formation and the fracture of the metal junction are realized in the horizontal direction.

Drawings

For the purpose of making the objects and technical solutions of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a planar mechanically controllable cleaving device based on a flexible material.

Fig. 2 is a schematic diagram of a portion of a chip fabricated with a flexible material substrate.

Fig. 3 is an enlarged view of a key portion of a chip fabricated from a flexible material substrate.

Fig. 4 shows that the conductivity of the gold atomic junction decreases as the flexible substrate stretches as the piezoelectric moves upward until it breaks.

Fig. 5 shows that the conductivity of the silver atomic junction decreases as the flexible substrate stretches as the piezoelectric moves upward until it breaks.

Drawing of the figure in (a): the current device analyzer comprises a straight guide rail 1, a slide bar 2, a piezoelectric ceramic ejector rod 3, piezoelectric ceramic 4, a perforated substrate 5, a flexible substrate 6, a brass pressing sheet for pressing and fixing one end of a flexible film 7, a pressing sheet for fixing the tail end of the flexible film and the slide bar 8, a semi-fixed brass pressing sheet 9, a metal knot 10 and a circuit 11 of the current device analyzer.

Detailed Description

The following describes the embodiments of the present invention in detail with reference to the drawings.

Examples: cutting a TPU film (with the length of about 500mm and the width of 150 mm) with a proper size as a substrate, cutting a gold wire or a silver wire (with the length of about 100mm, the diameter of 100um and the purity of 99.99%) with a certain length, circular cutting the middle part of the metal wire by a surgical knife to form a suspended metal groove (9), and adhering the cut gold wire on a flexible film by using black glue (epoxy resin, STYCAST 2850 FT) to manufacture a chip to be tested. Placing the chip on a plane mechanical controllable cracking device, fixing the flexible chip (6) on the substrate (5) by two pressing sheets (7) and (9) respectively, and fixing the rest flexible film by the pressing sheet (8)Part is fixed with the slide bar, and when the bottom piezoelectric device (4) moves up and down in the vertical direction, the push rod (3) on the piezoelectric drives the slide bar (2) connected to the straight guide rail (1) to move in the vertical direction, so that the flexible film (6) is stretched to generate transverse displacement, and a fixed bias voltage of 100mV (11) is applied to two ends of the metal junction, so that the measurement of dynamic electrical signals in the stretching and compressing processes of the metal junction is realized. When the piezoelectric ceramic moves upwards, the transverse stretching of the flexible chip is driven, the metal junction is gradually stretched, and the integral multiple G can be gradually observed ₀ (G ₀ Single atom junction conductance value) until final cleavage.

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

Claims

1. A plane mechanical controllable cracking method based on flexible materials is characterized in that: the device takes a flexible material as a substrate to realize metal atom level fracture in the horizontal direction and comprises a substrate with holes, piezoelectric ceramics, a TPU flexible chip, a straight guide rail and a slide bar; the substrate is a rectangular substrate with holes, the TPU flexible chip is fixed on the substrate and integrally fixed on the bracket of the piezoelectric ceramic, so that the ejector rod fixed on the piezoelectric ceramic can just penetrate out of the holes of the substrate; the TPU flexible chip comprises a strip-shaped flexible film and a gold thread fixed above the strip-shaped flexible film, and the gold thread with a notch in the middle is fixed above the flexible film by using black glue; the TPU flexible chip is fixed in a sectionally fixed mode, namely two ends fixed on a substrate and one end connected with a slide bar, one end of the TPU flexible chip fixed on the substrate is tightly fixed on the substrate through a brass pressing piece, the other end of the TPU flexible chip is also fixed on the substrate through the brass pressing piece, but is not completely fixed, a certain gap is reserved between a flexible film and the brass pressing piece, the flexible film of the TPU flexible chip can move freely in the horizontal direction, the rest part is connected with the slide bar of a straight guide rail through the gap, the tail end of the slide bar is arranged on a piezoelectric ceramic ejector rod, when the piezoelectric ceramic moves up and down, the slide bar is driven to move along the vertical direction, the flexible film is further enabled to generate elastic deformation in the horizontal direction, the horizontal stretching of the flexible film can lead to the breakage of a gold wire fixed above the flexible film, and the shrinkage of the flexible film can lead to the reconnection of the gold wire.

2. The method for mechanically controlling a crack in a plane based on flexible materials according to claim 1, characterized in that: the piezoelectric ceramic is used as a support and is combined with a straight guide rail with a slide bar, so that the slide bar moves up and down along with the piezoelectric ceramic.

3. The method for mechanically controlling a crack in a plane based on flexible materials according to claim 1, characterized in that: the flexible film is displaced when being stretched, so that the metal electrode on the flexible film is driven to move and stretch the gold thread, and the atomic-level fracture process is realized.

4. The method for mechanically controlling a crack in a plane based on flexible materials according to claim 1, characterized in that: the flexible material is not limited to TPU materials, and other flexible films can achieve an atomic level fracture process.

5. The method for mechanically controlling a crack in a plane based on flexible materials according to claim 1, characterized in that: the electrode material can be observed to break at an atomic level using either gold or silver.