CN105174202A - Mechanically controllable break junction (MCBJ) device capable of realizing picometer grade continuous change with screw pitch differences - Google Patents

Abstract

The invention discloses a mechanically controllable break junction (MCBJ) device capable of realizing picometer grade continuous accuracy change of a distance between electrodes with screw pitch differences and a method. The invention belongs to a novel MCBJ device which can be applied to the field of molecule electronics and the field of sensors. The distance between the two electrodes can be controlled at the picometer grade accuracy through actions of slight screw pitch differences among different screw pitches of a coaxial screw rod on a nanometer splitting device chip, so that construction of a single-molecule junction is realized; research of the characteristics of the single-molecule junction is realized; and valuable reference is provided for research of single-molecule devices.

Description

A mechanically controllable cracking device that realizes continuous change of picometer level by using pitch difference

technical field

The invention relates to a mechanical device for constructing a nanometer dot electrode pair monomolecular junction, and specifically relates to the fields of molecular electronics, micro-nano electronics and the like.

Background technique

Mechanically controllable split junction devices are widely used in the research and manufacture of molecular electronic devices such as molecular switches, molecular ballasts, and molecular field effect transistors due to their superior stability and precise controllability. In the existing technology, the piezoelectric effect can be used to control the deformation of the substrate at the nanoscale, but the precision is still insufficient, and there is a problem of insufficient driving force of low-temperature piezoelectric materials. In addition, there is a device that utilizes gear transmission to achieve mechanically controllable fission, but the device manufactured using this principle cannot meet the ideal requirements in terms of continuous change due to the inevitable backlash.

In order to solve the problems of low temperature, continuous, high precision, etc., the present invention proposes the use of stepping motor drive, combined with screw pitch difference to invent and manufacture a mechanically controllable cracking device that can achieve continuous change at low temperature and high precision .

Contents of the invention

The purpose of the present invention is to solve the problems of low temperature, continuous, high precision, etc. Continuously variable mechanically controllable cracking device.

The technical scheme adopted in the present invention is:

A mechanically controllable cracking device that utilizes pitch difference to achieve picometer-level continuous change, characterized in that it includes a top cover, a column, a linear guide rail, a push rod, an upper nut, a screw, an upper floating plate, a side frame plate, a lower nut, The lower floating plate, coupling, motor seat, motor, base and support rods; the top cover, the columns on both sides and the base are fixedly connected to form a square frame structure, which serves as the skeleton of the entire mechanical device and mainly supports the entire mechanical device There are two linear guide rails, which are respectively fixed on the inner side of the column, and the side frame plates are respectively movably installed on the linear guide rails, so as to ensure that the side frame plates can move up and down along the linear guide rails under the push of the screw rod; The lower floating plate is fixed on the lower ends of the two side frame plates, and the nut fixed in the middle of the lower floating plate is threadedly matched with the lower end of the screw rod to form a screw pair; the two ends of the upper floating plate are fixed on the sliders on the linear guide rails on both sides, The upper nut fixed in the middle is installed on the thread of the upper end of the screw and forms another screw pair; the lower end of the screw is connected with the motor installed in the motor base through a coupling, and the motor base is installed on the base. The upper end of the screw A push rod is installed; a support rod is respectively installed on the upper ends of the two side frame plates, and the nano splitting device chip is placed between the lower ends of the two support rods and the upper ends of the push rods.

When the stepping motor works, the coupling and the screw rotate together with the stepping motor, the thread at the upper end of the screw pushes the upper floating plate and the ejector rod to move, and the thread at the lower end of the screw pushes the lower floating plate and the side frame to move.

The upper floating plate and the ejector rod are fixed together and move together under the push of the thread at the upper end of the screw rod; the lower floating plate and the side frame plate are fixed together and move together under the push of the thread at the lower end of the screw rod; the upper floating plate and the lower floating plate There is no fixation between them, and they move at different speeds under the push of the upper and lower threads of the screw respectively.

When the screw rotates forward, the upper thread rotates with the screw for one revolution, pushing the upper floating plate and the ejector rod to move upwards by 0.95 mm, and the lower end thread rotates with the screw for one revolution, pushing the upper floating plate and the side shelf plate to move upwards by 1 mm; when the screw reverses, The thread at the upper end rotates with the screw for 1 revolution, pushing the upper floating plate and the ejector rod down 0.95mm, and the thread at the lower end rotates with the screw for 1 revolution, pushing the upper floating plate and the side frame to move down 1mm.

The nano-splitting device chip includes a suspended nano-gold bridge, the narrowest cross-sectional area of the gold bridge is 40nm×40nm, and the bending of the chip will eventually break the gold bridge to form two separate needle-shaped nano-electrodes; by bending or Stretching the chip can increase or reduce the distance between the two electrodes; the chip, the attenuation factor r=ΔZ/ΔX, ΔZ is the amount of change in the displacement of the center of the chip in the Z direction, ΔX is the amount of change in the distance between the two electrodes, and the attenuation factor r can reach 1×10 ^-6 , and the displacement accuracy of the chip center in the vertical Z direction can reach nanometer level. The present invention also provides a method for using the mechanically controllable splitting device to construct a nano-electrode pair single-molecule junction. The specific steps of the method are as follows:

Paste the chip of the nano-splitting device on the lower ends of the poles at both ends. The ejector pin just supports the middle position of the chip. The chip is clamped by the poles at both ends and the ejector pin at three points. Start the stepping motor to work, and the stepping motor drives the coupling The device and the screw rotate together. Under the push of the thread at the upper end of the screw, the upper floating plate and the ejector rod move together. Under the push of the thread at the lower end of the screw, the lower floating plate and the side shelf plate move together; when the ejector rod touches the bottom surface of the nano-splitting device chip , the chip of the nano-splitting device begins to be squeezed between the ejector rod and the poles at both ends, and the chip of the nano-splitting device produces a slight bending deformation under the action of the extrusion force, thereby causing the chip of the nano-splitting device to break; By controlling the forward rotation and reverse rotation of the stepping motor, when the screw rotates forward, the upper thread rotates with the screw for one revolution, pushing the upper floating plate and the ejector rod to move upward by 0.95mm, and the lower end thread rotates with the screw for one revolution, pushing the upper floating plate and the side frame The plate moves up 1mm; when the screw is reversed, the upper thread rotates with the screw for one revolution, pushing the upper floating plate and the ejector rod down 0.95mm, and the lower end thread rotates with the screw for one revolution, pushing the upper floating plate and the side shelf plate down 1mm, Utilizing the pitch difference between the two ends of the thread can realize picometer-level precise control of the break distance of the chip of the nano-splitting device to form a single-molecule junction.

Advantages and beneficial effects of the present invention:

(1) The present invention is driven by a stepping motor, and the driving force is less affected by temperature, which overcomes the problem of insufficient driving of low-temperature piezoelectric materials.

(2) The present invention utilizes pitch difference to realize picometer-level mechanically controllable cracking, and since the thread is continuous, it overcomes the problem that the nesting of gears cannot be continuously changed.

Description of drawings

Figure 1 is a diagram of a mechanically controllable fissure junction (MCBJ) device that can achieve continuous change at the picometer level.

Reference signs: 1, top cover, 2, column, 3, linear guide rail, 4, ejector rod, 5, upper nut, 6, screw rod, 7, upper floating plate, 8, side frame plate, 9, lower nut, 10, Lower floating plate, 11, shaft coupling, 12, motor seat, 13, motor, 14, base, 15, pole.

In order to understand the technical features, purpose and effects of the present invention more clearly, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

Detailed ways

Example 1

As shown in Figure 1, the mechanically controllable cracking device that uses the pitch difference to realize continuous changes at the picometer level, the device includes a top cover 1, a column 2, a linear guide rail 3, a push rod 4, an upper nut 5, a screw rod 6, and a floating plate 7. Side frame plate 8, lower nut 9, lower floating plate 10, coupling 11, motor seat 12, motor 13, base 14 and pole 15; the top cover, the columns on both sides and the base are fixedly connected to form a word Type frame structure, as the skeleton of the whole mechanical device, mainly plays the role of supporting the whole mechanical device; there are two linear guide rails, which are respectively fixed on the inner side of the column, and the side frame plates are respectively movably installed on the linear guide rails for Ensure that the side frame plate can move up and down along the linear guide rail under the push of the screw rod; the lower floating plate is fixed on the lower ends of the two side frame plates, and the lower nut fixed in the middle of the lower floating plate is threadedly matched with the lower end of the screw rod to form a screw pair; The two ends of the upper floating plate are fixed on the sliders on the linear guide rails on both sides, and the upper nut fixed in the middle is installed on the thread of the upper end of the screw to form another screw pair; the lower end of the screw is connected by a coupling The motor is connected in the motor seat, the motor seat is installed on the base, a push rod is installed on the upper end of the screw rod; a support rod is installed on the upper ends of the two side frame plates, and the lower end of the two support rods and the upper end of the push rod are installed The space is used to place the nano-splitting device chip.

The upper floating plate and the ejector rod are fixed together and move together under the push of the thread at the upper end of the screw rod; the lower floating plate and the side frame plate are fixed together and move together under the push of the thread at the lower end of the screw rod; the upper floating plate and the lower floating plate There is no fixation between them, and they move at different speeds under the push of the upper and lower threads of the screw respectively.

Purchase coupling (11) (MCKL10-2-4), linear guide (3) (SSE2BS8-130), stepper motor (13) (Faulhaber DC motor) according to Figure 1, assemble the device, and install the DC motor (13 ) to connect to the computer.

Adjust the device to the initial state, that is, the upper floating plate (7) and the lower floating plate (10) are at the lowest position, and the prepared nano-splitting device chip is clamped between the ejector rod (4) and the support rod (15). Control the DC motor (13) to make the motor rotate at a constant speed, and it can be observed that the relative position between the whole formed by the lower floating plate (10) and the side frame plate (8) and the upper floating plate (7) changes, and the chip of the nano-splitting device occurs. Bending deformation, the amount of deformation gradually increases with the rise of the upper and lower floating plates until the nano-electrodes on the chip break to form nano-electrode pairs. At this time, by controlling the forward rotation and reverse rotation of the stepping motor (13), high-precision The distance between the nano-electrode pairs can be adjusted continuously and continuously.

Relevant description of the present invention:

1. All the features, methods or steps in the process disclosed in the present invention can be combined in any way except for mutually exclusive features or steps.

2. Any feature disclosed in the present invention, unless specifically stated, can be replaced by other alternative features that are equivalent or have similar purposes. That is, unless expressly stated otherwise, each feature is only one example of a series of equivalent or similar features.

3. In the present invention, in order to ensure high-precision regulation at the picometer level, the material of the mechanical device is high-hardness stainless steel, and other high-hardness materials can also be used.

Claims (4)

1. one kind utilizes pitch difference to realize micromicron level continually varying Mechanical controllable to split knot device, it is characterized in that, comprise overhead guard, column, line slideway, push rod, top nut, screw rod, floating version, lateral shelf plate, lower nut, lower kickboard, shaft coupling, motor cabinet, motor, base and pole; The column of described overhead guard, both sides and base are fixedly connected into hollow frame structure, as the skeleton of whole mechanical device, mainly play a part to support whole mechanical device; Described line slideway has two, is separately fixed at the inner side of column, and described lateral shelf plate is movably arranged on line slideway respectively, for ensureing that lateral shelf plate can move up and down along line slideway under the promotion of screw rod; Described lower kickboard is fixed on the lower end of two lateral shelf plates, and lower nut fixing in the middle of lower kickboard and the lower end threaded engagement of screw rod form lead screw pair; The two ends of described upper kickboard are fixed on the slide block on the line slideway of both sides, and the top nut fixed by centre is arranged on the threaded upper ends place of screw rod and forms another lead screw pair; The lower end of described screw rod is connected with the motor be arranged in motor cabinet by shaft coupling, and motor cabinet is arranged on base, and the upper end of screw rod is provided with a push rod; The upper end of two lateral shelf plates is separately installed with a pole, for placing nanometer splitting device chip between the lower end of two poles and the upper end of push rod; When stepper motor works, shaft coupling rotates with stepper motor together with screw rod, and screw rod threaded upper ends promotes upper kickboard and push rod moves, and screw rod lower end screw thread promotes lower kickboard and lateral shelf plate moves.

2. according to claim 1ly utilize pitch difference to realize micromicron level continually varying Mechanical controllable to split knot device, it is characterized in that, described upper kickboard and push rod are fixed together, and move together under the promotion of screw rod threaded upper ends; Described lower kickboard and lateral shelf plate are fixed together, and move together under the promotion of screw rod lower end screw thread; Unfixing between described upper kickboard and lower kickboard, move with different speed under the promotion of screw rod threaded upper ends and lower end screw thread respectively.

3. according to claim 1ly utilize pitch difference to realize micromicron level continually varying Mechanical controllable to split knot device, it is characterized in that, when described screw rod rotates forward, threaded upper ends rotates 1 week with screw rod, in promotion, kickboard and push rod move up 0.95mm, lower end screw thread rotates 1 week with screw rod, and in promotion, kickboard and lateral shelf plate move up 1mm; During screw rod reversion, threaded upper ends rotates 1 week with screw rod, and in promotion, kickboard and push rod move down 0.95mm, and lower end screw thread rotates 1 week with screw rod, and in promotion, kickboard and lateral shelf plate move down 1mm;

Described nanometer splitting device chip comprises a unsettled nanometer Golden Bridge, and the narrowest middle part cross-sectional area of Golden Bridge is 40nm × 40nm, and the bending of chip finally can make Golden Bridge rupture, and forms two acicular nanometer electrodes separated; Can increase or reduce two interelectrode distances by bending or unfolding chip; Described chip, decay factor r=Δ Z/ Δ X, Δ Z are the variable quantities of chip center's displacement in z-direction, and Δ X is the variable quantity of two interelectrode distances, and decay factor r can reach 1 × 10 ^-6, and the displacement accuracy of chip center in vertical Z-direction can reach nanoscale.

4. use the Mechanical controllable described in claim 1 to split knot device and construct the method that nano-electrode ties unimolecule, it is characterized in that the method concrete steps are as follows:

Nanometer splitting device chip is attached to the lower end of two ends pole, the centre position of push rod just in time supporting chip, chip is clamped by two ends pole and push rod 3, start stepper motor work, stepper motor drives shaft coupling to rotate together with screw rod, and under the promotion of screw rod threaded upper ends, upper kickboard moves together with push rod, under the promotion of screw rod lower end screw thread, lower kickboard moves together with lateral shelf plate; When the bottom surface of ejector pin contact nanometer splitting device chip, nanometer splitting device chip starts to be subject to the extruding force between push rod and two ends pole, nanometer splitting device chip produces small Bending Deformation under the effect of extruding force, and then makes nanometer splitting device chip fracture; By rotating and reverse of control step motor, when screw rod rotates forward, threaded upper ends rotates 1 week with screw rod, and in promotion, kickboard and push rod move up 0.95mm, and lower end screw thread was with screw rod rotation 1 week, and in promotion, kickboard and lateral shelf plate move up 1mm; During screw rod reversion, threaded upper ends rotates 1 week with screw rod, in promotion, kickboard and push rod move down 0.95mm, lower end screw thread rotates 1 week with screw rod, in promotion, kickboard and lateral shelf plate move down 1mm, utilize the pitch difference of two ends screw thread to realize spacing that micromicron level accurately controls nanometer splitting device chip fracture, forms unimolecule knot.