Plasma in-situ sample holder for electron microscopy
By integrating microelectrodes and MEMS heating chips into the TEM sample rod tip, the integration challenge of plasma excitation and temperature control was solved, enabling efficient simulation of plasma catalytic reactions within the TEM, reducing costs and improving observation accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF CHINESE ACAD OF SCI
- Filing Date
- 2026-02-03
- Publication Date
- 2026-05-29
AI Technical Summary
Existing in-situ TEM sample holders lack integrated plasma generation and control functions, making it difficult to achieve efficient plasma excitation at the front end of the TEM sample holder that is compatible with high-vacuum electron microscopes. This results in complex structures, high costs, and an inability to directly observe the interaction process between plasma and catalysts.
Microelectrodes and dielectric barrier layers are integrated inside the TEM sample rod to form a plasma reaction zone. Combined with a MEMS heating chip, plasma excitation and temperature control of the sample are achieved. Electrical safety and high vacuum isolation are ensured through micro-nano fabrication and vacuum design.
It enables the synchronous or sequential application of plasma excitation and temperature control to samples within a TEM, simulating the real catalytic reaction environment, reducing manufacturing costs and improving observation accuracy, and directly revealing the dynamic behavior in plasma catalysis.
Smart Images
Figure CN122117732A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of transmission / scanning electron microscope accessories and nanomaterial measurement, specifically to a plasma in-situ sample holder for transmission / scanning electron microscopes. Background Technology
[0002] Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) can overcome the optical diffraction limit, enabling direct observation of the atomic-scale structure of materials, and have become indispensable analytical tools in materials science, nanotechnology, and catalysis. As scientific research shifts from static characterization to understanding dynamic processes, traditional static observation can no longer meet the research needs for real-time structural evolution of materials under external fields (such as heat, force, electricity, and atmosphere). Therefore, in-situ transmission / scanning electron microscopy has emerged. This technique uses a specially designed sample holder to apply an external field (such as heat, force, electricity, or atmosphere) to the sample within the TEM chamber, while simultaneously performing real-time atomic-scale observation, thereby directly revealing the dynamic structural evolution and performance correlation mechanisms of materials under external fields. The in-situ sample holder is the core component of this technique.
[0003] Among various external fields, thermal stimulation is one of the most commonly used and important research methods. However, in many fields involving gas-solid phase reactions, especially in heterogeneous catalysis research, simple heating is insufficient to simulate the real reaction environment. Catalytic processes often involve a series of complex steps, such as the activation of reactant gases, surface adsorption, intermediate formation, and product desorption, among which the activation state of the reactant gases is crucial. Plasma technology, as a highly efficient gas activation method, can dissociate, ionize, or excite gas molecules to highly active states (such as active particles, free radicals, etc.) at relatively low temperatures, thereby significantly reducing the reaction activation energy, improving catalytic efficiency, or achieving catalytic reactions under mild conditions.
[0004] Although plasma catalysis research is of great significance, there is currently a lack of tools capable of directly observing the interaction between plasma and catalysts at the atomic scale. Traditional characterization methods are mostly limited to offline analysis of samples after plasma treatment, failing to capture the instantaneous evolution of catalyst surface structure, composition, valence state, and the dynamic behavior of active sites under plasma irradiation. Combining plasma excitation with in-situ electron microscopy holds promise for directly revealing key scientific issues in plasma catalysis.
[0005] However, existing commercially available or domestically developed in-situ TEM sample holders primarily focus on heating, stretching, and electrical measurements. In-situ sample holders integrating plasma generation and control functions are either nonexistent or extremely immature. The main technical challenge lies in integrating a highly efficient plasma excitation unit compatible with high-vacuum electron microscopy within the limited space at the front end of the TEM sample holder (typically with a diameter ≤3 mm), ensuring it does not interfere with the electron beam path and achieves uniform excitation and precise parameter control of the sample region. Furthermore, such complex functional integration often results in complex sample holder structures, high manufacturing costs, and high technical barriers, limiting its development and application. Summary of the Invention
[0006] To solve the above-mentioned technical problems, the present invention provides a plasma in-situ sample rod for electron microscopes, comprising a rod head, a rod body, and a handle, wherein the rod head is sealed to the front end of the rod body, and the handle is sealed to the rear end of the rod body; A plasma generating unit and a load-bearing component are integrated inside the rod head. The plasma generating unit includes two parallel microelectrodes, and a plasma reaction zone is formed between the two microelectrodes. The support assembly is located at the center of the plasma reaction zone and is used to support and heat the sample; the support assembly includes a heating chip, and an electron beam transparent window is provided at the center of the heating chip.
[0007] Preferably, the surface of the microelectrode is covered with a uniform dielectric barrier layer, and the dielectric barrier layer and the two microelectrodes form a micro dielectric barrier discharge cavity.
[0008] Preferably, the dielectric barrier layer is in the form of a thin film, and more preferably, the dielectric barrier layer is made of quartz glass thin film.
[0009] Preferably, both microelectrodes are connected to the plasma power source via independent fine wires.
[0010] Preferably, the heating chip is provided with a micro heating circuit and a temperature sensing circuit, which are integrated on the surface of the heating chip through micro-nano fabrication.
[0011] Preferably, the heating chip is connected to the chip circuit board via multiple electrode pins, and the heating chip is electrically connected to an external control interface via multiple thin wires.
[0012] Preferably, the rear end of the handle is provided with an independent external interface group, including a plasma power interface and a MEMS temperature control power and signal interface, which provide power to the microelectrode and the heating chip, respectively.
[0013] Preferably, a ceramic fixing plate is provided inside the rod head, which is fixed inside the rod head to fix and position the microelectrode.
[0014] Preferably, the ceramic fixing plate has two through holes corresponding to the two microelectrodes. The axes of the two through holes are parallel and extend along the axial direction of the ceramic fixing plate. The through holes are used to install the microelectrodes.
[0015] Preferably, a sealing ring is provided at the point where the microelectrode protrudes from the rod body.
[0016] The technical effects and advantages of this invention are as follows: 1. The plasma in-situ sample rod of the present invention, through the plasma generation unit and MEMS heating chip integrated in the sample rod head, can synchronously or sequentially apply plasma excitation and precise temperature control to the sample under test, directly simulating the complex environment in real plasma catalytic reaction. Moreover, the sample rod has a simple structural design and greatly reduces manufacturing costs.
[0017] 2. In this invention, the surface of the heating chip integrates a micro heating circuit and a temperature sensing circuit through micro-nano fabrication, which can rapidly and uniformly heat the sample in the transparent window area of the electron beam, and realize millisecond-level real-time temperature monitoring and feedback control.
[0018] 3. In this invention, the fine wires connecting the microelectrode and the heating chip are insulated from each other inside the rod body, which can eliminate signal crosstalk and ensure electrical safety. At the same time, a sealing ring is used to strictly seal the point where the fine wires pass through, ensuring effective isolation between the environment inside the sample rod and the ultra-high vacuum of the electron microscope. Attached Figure Description
[0019] Figure 1 This is an overall view of the plasma in-situ sample rod illustrated in the embodiment.
[0020] Figure 2 This is a schematic diagram of the front structure of the rod head in the plasma in-situ sample rod, as illustrated in the embodiment.
[0021] Figure 3 This is a schematic diagram of the side shaft structure of the rod head in the plasma in-situ sample rod, as illustrated in the embodiment.
[0022] Figure 4 This is a schematic diagram of a heated chip in a plasma in-situ sample holder, as illustrated in an embodiment.
[0023] Figure 5 This is a schematic diagram of the structure of the rod head in the plasma in-situ sample rod, as illustrated in the embodiment.
[0024] In the diagram: 1. Rod head; 2. Rod body; 3. Handle; 4. Microelectrode; 5. Dielectric barrier layer; 6. Plasma reaction zone; 7. Heating chip; 8. Electron beam transparent window; 9. Micro heating circuit; 10. Temperature sensing circuit; 11. Fine wire; 12. Electrode probe; 13. Chip circuit board; 14. Ceramic fixing plate; 15. Sealing ring; 16. Plasma power interface; 17. Signal interface; 18. First screw; 19. Pressure plate; 20. Second screw. Detailed Implementation
[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.
[0026] Please see Figure 1 In this embodiment, a plasma in-situ sample rod for an electron microscope is provided, including a rod head 1, a rod body 2 and a handle 3. The rod head 1 is sealed to the front end of the rod body 2, and the handle 3 is sealed to the rear end of the rod body 2. It adopts a segmented modular design to adapt to the narrow space of the electron microscope sample chamber and ensure vacuum sealing.
[0027] Specifically, the external dimensions of the rod head 1 are the same as those of the TEM in-situ liquid sample rod in the prior art. The plasma generating unit and the carrier component are integrated inside the rod head 1. The plasma generating unit includes two microelectrodes 4, which are arranged in parallel relative to each other, and a plasma reaction zone 6 is formed between the two microelectrodes 4.
[0028] Furthermore, a uniform dielectric barrier layer is covered on the surface of the microelectrode 4, and the dielectric barrier layer and the two microelectrodes 4 form a micro dielectric barrier discharge cavity.
[0029] Preferably, the dielectric barrier layer is in the form of a thin film and is made of quartz glass thin film 5.
[0030] In this embodiment, after the reactive gas is introduced into the sample attachment using an environmental transmission electron microscope, a low-temperature, uniform and stable plasma reaction zone 6 is generated in the narrow space between the two microelectrodes 4 when a high-frequency voltage is applied.
[0031] In this embodiment, the support component is located at the center of the plasma reaction zone between the two microelectrodes 4, and serves as a sample support and temperature control platform.
[0032] Specifically, the carrier component includes a heating chip 7, with an electron beam transparent window 8 located at the center of the heating chip 7, which is used to carry micro-nano samples and ensure unobstructed transmission of the electron beam.
[0033] Furthermore, the heating chip 7 is equipped with a micro heating circuit 9 and a temperature sensing circuit 10. The micro heating circuit 9 and the temperature sensing circuit 10 are integrated on the surface of the heating chip 7 through micro-nano fabrication, which can rapidly and uniformly heat the sample in the electron beam transparent window 8 area and realize millisecond-level real-time temperature monitoring and feedback control.
[0034] Preferably, the heating chip 7 is a MEMS micro-heating chip, which can improve monitoring accuracy.
[0035] The plasma in-situ sample rod of the present invention, through the integration of a plasma generation unit and a MEMS heating chip at the tip of the sample rod, can apply plasma excitation and precise temperature control to the sample under test synchronously or sequentially, directly simulating the complex environment of the synergistic effect of "active species" and "thermal effect" in real plasma catalytic reactions. It has significant scientific value and application potential for cutting-edge fields such as plasma catalysis, energy materials, and extreme condition materials science. Moreover, the sample rod has a simple structural design and greatly reduces manufacturing costs.
[0036] Furthermore, both microelectrodes 4 are connected to the plasma power supply via independent thin wires 11. The heating chip 7 is connected to the chip circuit board 13 via four electrode pins 12, and then electrically connected to the external control interface via multiple thin wires 11.
[0037] Multiple thin wires 11 pass through the hollow rod body 2 and extend axially to the rear end of the handle 3. The rear end of the handle 3 is provided with an independent external interface group, including a plasma power interface 16 and a MEMS temperature control power and signal interface 17, which provide power to the microelectrode 4 and the heating chip 7, respectively.
[0038] The plasma power interface 16 is used to connect an external DC power supply to provide the high-frequency voltage required to excite the plasma for the microelectrode 4.
[0039] MEMS temperature control power and signal interface 17 is used to connect to an external programmable temperature controller, power the micro heating circuit 9 and receive its temperature measurement signal to achieve closed-loop precise temperature control.
[0040] Furthermore, all external interface groups are sealed to create a vacuum environment inside the sample holder.
[0041] Furthermore, a ceramic fixing plate 14 is provided inside the rod head 1. The ceramic fixing plate 14 is fixed inside the rod head 2 and is used to fix and position the microelectrode 4. The ceramic fixing plate 14 has two through holes corresponding to the two microelectrodes 4. The axes of the two through holes are parallel and the through holes extend along the axial direction of the ceramic fixing plate 14. The through holes are used to install the microelectrode 4. The distance between the two microelectrodes 4 can be adjusted by adjusting the distance between the two through holes, and the two microelectrodes 4 remain parallel after installation.
[0042] Inside the rod head 1, an open cavity is formed on the side of the ceramic fixing plate 14 near the rod body 2. The opening of the cavity is provided with a threaded or snap-fit structure for connecting the rod body 2. The rod body 2 is also provided with a corresponding threaded or snap-fit connection structure. The rod head 1 and the rod body 2 are sealed together at one end. A sealing ring can also be provided at the connection to improve the sealing performance of the connection.
[0043] Furthermore, the shaft 2 and the handle 3 can also be connected by a threaded or snap-fit structure, with a sealing ring at the connection point to form a sealed connection.
[0044] The rod head 1 has a ceramic insulating tube installed in the cavity with an opening to fix the fine wire 11. A sealing ring 15 is installed where the microelectrode 4 passes through the rod body 1. The sealing ring 15 is used to seal the sample rod to ensure effective isolation between the environment inside the sample rod and the ultra-high vacuum of the electron microscope. Preferably, the sealing ring 15 is a rubber sealing O-ring.
[0045] The fine wire 11 extends along the interior of the hollow rod body 2 to the rear end of the handle 3. This design avoids signal crosstalk and ensures electrical safety. The fine wires 11 leading to the microelectrode 4 and heating chip 7 of the plasma high voltage are insulated from each other inside the rod body 2.
[0046] Furthermore, the heating chip 7 is fixed to the rod head 1 by the pressure plate 19 and the first screw 18, and the chip circuit board 13 is fixed to the rod head 1 by the second screw 20.
[0047] When using the sample rod of the present invention, the catalyst sample to be observed is first dispersed in ethanol and then dropped onto the surface of the electron beam transparent window 8. After being dried by an infrared lamp, it is loaded and fixed on the chip platform of the rod head 1. The heating chip 7 is fixed by the first screw 18 and the pressure plate 19, and then the chip circuit board 13 is fixed by the second screw 20, so that the heating chip 7 and the electrode contact pin 12 are connected.
[0048] Taking a transmission electron microscope as an example, the assembled sample rod is inserted into the sample stage of the transmission electron microscope and pushed to the working position. The target temperature or heating program is set by the temperature controller, which powers the micro heating circuit 9 and receives its temperature measurement signal, so as to realize the precise and stable heating or cooling of the sample and to perform in-situ observation at different temperatures.
[0049] A pre-set reaction gas (such as H2) is introduced into the sample accessory through the environmental transmission electron microscope gas path system. (O2, CO2, etc.), then the plasma DC discharge power supply is started, and the intensity and state of the plasma reaction zone are excited and controlled by adjusting the voltage.
[0050] It is understood that, in this embodiment, the thermal field and the plasma external field can be applied independently according to actual needs, or the two can be combined to realize a variety of complex coupled experimental modes such as "heating the plasma first", "plasma accompanied by heating", or "plasma treatment under temperature program", and the evolution process of sample structure, morphology and composition can be recorded in real time in the electron microscope.
[0051] This in-situ plasma sample holder, through precise micro-nano integration and vacuum design, achieves for the first time a highly efficient fusion of plasma excitation and precise control at the front end of a standard sample holder. It not only solves the challenge of creating a controllable plasma environment within a TEM, but also provides the ability to independently or collaboratively program and control the plasma and thermal fields, thereby enabling the direct revelation of the dynamic behavior of materials under simulated real catalytic reaction environments at the atomic scale.
[0052] It should be understood that the plasma in-situ sample holder of this application is not limited to transmission electron microscopy (TEM) and scanning electron microscopy (SEM), but can also be used with other electron microscopes.
[0053] This device has significant scientific value and application potential for advancing basic research in cutting-edge fields such as plasma catalysis, energy material synthesis and conversion, and surface and interface science.
[0054] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.
Claims
1. A plasma in-situ sample holder for an electron microscope, characterized in that, It includes a club head (1), a shaft (2) and a handle (3), wherein the club head (1) is sealed to the front end of the shaft (2) and the handle (3) is sealed to the rear end of the shaft (2); A plasma generating unit and a bearing assembly are integrated inside the rod head (1). The plasma generating unit includes two parallel microelectrodes (4), and a plasma reaction zone is formed between the two microelectrodes (4). The support component is located at the center of the plasma reaction zone and is used to support and heat the sample; the support component includes a heating chip (7) and an electron beam transparent window (8) is provided at the center of the heating chip (7).
2. The plasma in-situ sample holder for an electron microscope according to claim 1, characterized in that, The surface of the microelectrode (4) is covered with a uniform dielectric barrier layer, and the dielectric barrier layer and the two microelectrodes (4) together form a micro dielectric barrier discharge cavity.
3. The plasma in-situ sample holder for an electron microscope according to claim 2, characterized in that, The dielectric barrier layer is in the form of a thin film, preferably made of a quartz glass thin film (5).
4. The plasma in-situ sample holder for an electron microscope according to claim 3, characterized in that, Both of the microelectrodes (4) are connected to the plasma power source via separate thin wires (11).
5. The plasma in-situ sample holder for an electron microscope according to claim 1, characterized in that, The heating chip (7) is provided with a micro heating circuit (9) and a temperature sensing circuit (10), which are integrated on the surface of the heating chip (7) through micro-nano processing.
6. The plasma in-situ sample holder for an electron microscope according to claim 5, characterized in that, The heating chip (7) is connected to the chip circuit board (13) through multiple electrode pins (12), and the heating chip (7) is electrically connected to the external control interface through multiple thin wires (11).
7. The plasma in-situ sample holder for an electron microscope according to claim 1, characterized in that, The handle (3) has an independent external interface group at its rear end, including a plasma power interface (16) and a MEMS temperature control power and signal interface (17), which provide power to the microelectrode (4) and the heating chip (7), respectively.
8. The plasma in-situ sample holder for an electron microscope according to claim 1, characterized in that, The rod head (1) is provided with a ceramic fixing plate (14) inside. The ceramic fixing plate (14) is fixed inside the rod head (2) and is used to fix and position the microelectrode (4).
9. A plasma in-situ sample holder for an electron microscope according to claim 8, characterized in that, The ceramic fixing plate (14) has two through holes corresponding to the two microelectrodes (4). The axes of the two through holes are parallel and extend along the axial direction of the ceramic fixing plate (14). The through holes are used to install the microelectrodes (4).
10. A plasma in-situ sample holder for an electron microscope according to claim 1, characterized in that, The microelectrode (4) protrudes from the rod (1) and is provided with a sealing ring (15).