In-situ transmission electron microscope sample rod integrated with scanning tunneling microscope and detection method

Abstract

The application discloses an in-situ transmission electron microscope sample rod integrated with a scanning tunneling microscope and a detection method, and belongs to the technical field of electron microscopes. The sample rod comprises a sample rod body, an axial STM probe assembly integrated with the sample rod head, a front-end rotatable sample support and a linear-rotation conversion driving mechanism. The linear-rotation conversion driving mechanism converts axial linear motion into angular displacement, and drives the rotatable sample support to be in-situ flipped by 90 DEG between a horizontal TEM mode and a vertical STM mode. In the STM mode, the sample surface is parallel to the electron beam and opposite to the STM probe tip, and at the same time, an automatic electrical contact assembly is closed to realize reliable grounding of the sample. The application effectively solves the problems of geometric visual angle conflict, electron beam scattering interference and unstable grounding existing in the traditional combined technology, and realizes lossless, high signal-to-noise ratio in-situ switching of transmission imaging and tunneling current analysis in a vacuum environment.

Description

Technical Field

[0001] This invention relates to the field of high-end electron microscope instruments and equipment technology. Specifically, it relates to an in-situ transmission electron microscope sample holder and detection method for an integrated scanning tunneling microscope, which is used to achieve in-situ coupling of atomic-level transmission imaging and surface electronic state tunneling analysis in a TEM high-vacuum environment. Background Technology

[0002] Transmission electron microscopy (TEM) is the flagship tool in materials science for obtaining atomic-level bulk structure information. However, traditional TEM sample holders, limited by their geometric design, focus only on diffraction and imaging of transmission modes, lacking the ability to characterize material surface morphology and electronic density of states in situ. In contrast, scanning tunneling microscopy (STM), utilizing the quantum tunneling effect, is a powerful tool for probing localized electronic states on surfaces.

[0003] While existing technologies have attempted to integrate STM into TEM (such as US10520527B2 or Aduro-STM series), they generally suffer from core technical challenges: 1. Geometry and mode conflict: Existing designs mostly use fixed probes for lateral feeding, which prevents the sample from freely switching between "vertical electron beam (TEM mode)" and "parallel electron beam (STM mode)," resulting in the inability to simultaneously acquire bulk and surface information in the same micro-region.

[0004] 2. Severe signal interference: Under the bombardment of high-energy electron beams in TEM, secondary electron scattering and sample charging effects are easily generated, resulting in extremely low signal-to-noise ratio of STM tunneling current; at the same time, the strong magnetic field of the TEM pole piece seriously interferes with the positioning accuracy of piezoelectric ceramics.

[0005] 3. Unreliable grounding: Traditional designs have difficulty maintaining stable ohmic contact during dynamic operation, resulting in a floating potential of the sample and an inability to establish a stable tunneling bias.

[0006] Therefore, there is an urgent need for a new type of in-situ sample rod that can achieve non-destructive switching of modes in a vacuum, and has efficient electromagnetic shielding and automatic grounding functions.

[0007] To address these issues, this invention provides a novel sample holder that enables seamless switching between TEM transmission mode and STM scanning mode via a rotatable sample holder, while optimizing shielding, grounding, and stability to improve overall performance. Summary of the Invention

[0008] The core objective of this invention is to provide an in-situ TEM sample holder with integrated STM, which achieves seamless integration of transmission observation and STM detection within the confined space of the TEM pole piece through an innovative mechanical and electrical architecture.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides an in-situ transmission electron microscope sample holder for an integrated scanning tunneling microscope, comprising: The sample rod body includes a handle, a thicker rear rod, a thinner front rod, and a sample rod head connected in sequence. The STM probe assembly includes an STM probe and an upper drive shaft. The front end of the front thin rod has a mounting groove, in which the STM probe is placed. The tip of the STM probe points parallel to the axial direction of the sample rod body. The rear end of the STM probe is connected to the upper drive shaft, which is used to control the linear feed motion of the STM probe. A rotatable sample holder is set inside the sample rod head and hinged to the sample rod head at the rear end. In TEM mode, the sample surface on the rotatable sample holder is perpendicular to the TEM electron beam, and the position of the rotatable sample holder at this time is defined as the first position. In STM mode, the sample surface is parallel to the TEM electron beam and perpendicular to the tip of the STM probe, and the position of the rotatable sample holder at this time is defined as the second position. A linear-rotation conversion drive mechanism is connected to the back of the rotatable sample holder and is used to convert the linear displacement of the linear-rotation conversion drive mechanism along the sample rod axis into the angular displacement of the rotatable sample holder about the hinge, thereby causing the rotatable sample holder to flip in place between the first position and the second position. An automatic electrical contact assembly includes a first contact disposed on the rear end face of a rotatable sample holder and a second contact disposed on the fixed end face of a sample rod head; in STM scanning mode, the first contact and the second contact close to ground the sample to form a potential difference, thereby forming a tunneling current loop.

[0010] Preferably, the rotatable sample holder is a plate-like structure with a thickness that gradually increases from front to back, and holes are cut in it for transmitting electron beams; both the front and rear ends of the back of the rotatable sample holder are provided with wedge-shaped force-bearing structures, and both the front and rear wedge-shaped force-bearing structures are provided with fixing slots.

[0011] Preferably, the linear-rotation conversion drive mechanism includes a Y-shaped drive slider and a lower drive shaft; the lower drive shaft is connected to the rear end of the Y-shaped drive slider and is used to drive the Y-shaped drive slider forward or backward; the front end of the Y-shaped drive slider is provided with an upwardly protruding wedge-shaped force-applying structure, which can cooperate with the wedge-shaped force-receiving structure on the back of the rotatable sample holder, and drives the rotatable sample holder to flip upward when the Y-shaped drive slider retracts; the wedge-shaped force-applying structure is provided with a locking pin, which is used to lock with the fixing slot on the back of the rotatable sample holder to lock the rotatable sample holder.

[0012] Preferably, the automatic electrical contact assembly further includes a conductive reset spring, disposed at the second contact or as the second contact itself; in STM mode, the conductive reset spring is compressed to provide elastic contact force to ensure low-resistance grounding; when switching from STM mode to TEM mode, the conductive reset spring releases elastic potential energy to assist in the reset and flipping of the rotatable sample holder.

[0013] The present invention also provides a method for detecting an in-situ transmission electron microscope sample rod based on the aforementioned integrated scanning tunneling microscope, the method being used to detect the bulk information or surface information of the sample; When it is necessary to detect the bulk information of a sample, the following steps are included: S1. The lower drive shaft pushes the Y-type drive slider forward. When the locking pin on the Y-type drive slider is unlocked from the fixed slot at the rear end of the rotatable sample holder, the rotatable sample holder gradually flips downward to the first position under the power of the conductive reset spring. The Y-type drive slider moves forward until the locking pin locks with the fixed slot at the front end of the rotatable sample holder, forcibly locking the rotatable sample holder mechanically to the first position. At this time, the sample plane is perpendicular to the electron beam. S2. The upper drive shaft drives the STM probe to retract into the composite shielding structure. S3. Start the electron source of the in-situ transmission electron microscope to emit an electron beam, perform imaging or diffraction analysis and detection of the sample, and obtain the sample bulk information. When it is necessary to detect information on the surface of a sample, the following steps are included: 1) The lower drive shaft pushes the Y-type drive slider backward to release the lock on the fixed slot at the front end of the rotatable sample holder. During the backward movement of the Y-type drive slider, the retraction of the wedge-shaped force structure drives the rotatable sample holder to gradually rotate upward 90° to the second position. At this time, the first contact and the second contact are tightly closed, directly connecting the sample to the system ground, effectively discharging the accumulated charge and eliminating the charging effect. 2) The upper drive shaft drives the STM probe to extend out of the composite shielding structure. At this time, the rotatable sample holder and the composite shielding structure form an electron beam blocking cavity, which reduces background noise. 3) Activate the current feedback loop of the scanning tunneling microscope to establish a stable tunneling current, then start the grating scan, the STM probe collects the tunneling current signal and transmits it to the sample rod to obtain sample surface information.

[0014] Compared with the prior art, the present invention has the following significant advantages: 1. In-situ dual-mode non-destructive switching: For the first time, the sample is automatically flipped in a vacuum at 90°, which completely solves the contradiction of geometric perspective in the traditional STM-TEM combination, allowing users to obtain crystal structure and surface electronic state information at the same position without changing the sample holder.

[0015] 2. Ultimate signal-to-noise ratio optimization: Through a three-dimensional anti-interference system of "composite shielded cavity + in-situ preamplifier + automatic precision grounding", the noise floor of tunneling current is reduced to the limit, ensuring the authenticity of the data.

[0016] 3. High-reliability mechanical logic: The conductive reset spring serves as both the reset power source and the grounding contact, simplifying the mechanical structure. The wedge-shaped self-locking and closed-loop control ensure micron-level mechanical repeatability accuracy.

[0017] 4. Wide compatibility: The design is compatible with standard φ3mm TEM carrier mesh and mainstream TEM pole shoe interfaces, which has extremely high scientific research applicability and industrialization value. Attached Figure Description

[0018] Figure 1 A schematic diagram of the overall structure of the transmission electron microscope sample holder with integrated STM probe provided in the embodiments of this application.

[0019] Figure 2 This is a magnified schematic diagram showing the sample probe head in TEM mode, as provided in an embodiment of this application.

[0020] Figure 3 This is a partially enlarged schematic diagram showing the cooperation between the linear-rotation conversion drive mechanism and the sample holder provided in the embodiments of this application.

[0021] Figure 4 A schematic diagram of the Y-shaped drive device at the lower part of the sample rod provided in an embodiment of this application.

[0022] Figure 5 This is a schematic diagram of the overall structure of the front-end thin rod STM probe assembly provided in an embodiment of this application.

[0023] Figure 6 This is a schematic diagram of the sample rod handle and rear end connection structure provided in an embodiment of this application.

[0024] Figure 7 This is an exploded view of the STM probe assembly and composite shielding structure provided in the embodiments of this application.

[0025] Figure 8 This is a partially enlarged schematic diagram of the electrical contact point provided in an embodiment of this application.

[0026] Figure 9 This is a schematic diagram of the rotatable sample holder structure provided in an embodiment of this application.

[0027] In the picture: 1-Sample rod head; 11-Rotable sample holder; 12-Flexible rotating hinge; 13-First contact; 14-Fixing slot; 15-Y-type drive slider; 16-Locking pin; 17-Second contact; 18-Conductive reset spring.

[0028] 2-Front-end thin rod: 21-Electrostatic shielding shell, 22-Magnetic shielding coating, 23-STM probe, 24-In-situ preamplifier.

[0029] 3-Rear end thick rod: 31-Upper drive shaft, 32-Lower drive shaft, 33-Vacuum seal ring.

[0030] 4-Hand grip. Detailed Implementation

[0031] The present invention will be further described and illustrated below with reference to specific embodiments and accompanying drawings. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0032] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0033] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] This invention provides an in-situ transmission electron microscope sample holder for an integrated scanning tunneling microscope, such as... Figure 1 As shown, by setting up a 90° flip-type sample holder system and an axially telescopic STM probe assembly, in-situ non-destructive switching between TEM and STM modes can be achieved, thereby simultaneously acquiring bulk and surface information in the same micro-region.

[0035] The sample rod consists of a sample rod head 1, a thin front rod 2, a thick rear rod 3, and a handle 4 connected in sequence.

[0036] The sample holder contains an STM probe assembly, a rotatable sample holder 11, a linear-rotation conversion drive mechanism, and an automatic electrical contact assembly.

[0037] The STM probe assembly includes an STM probe 23, an upper drive shaft 31, and a composite shielding structure, such as Figure 5The front end of the sample rod 2 has a mounting groove, in which the STM probe 23 is placed, with the tip of the STM probe 23 pointing parallel to the axial direction of the sample rod. The rear end of the STM probe 23 is connected to an upper drive shaft 31, which is used to control the linear feed motion of the STM probe 23.

[0038] The composite shielding structure is used to block interference from the main electron beam and secondary scattered electrons of the transmission electron microscope on the tip of the STM probe 23, such as... Figure 5 and Figure 7 As shown, the structure includes a magnetic shielding coating 22 and an electrostatic shielding shell 21 that are coaxially wrapped around the STM probe 23. When in TEM mode, the STM probe 23 retracts into the composite shielding structure under the control of the upper drive shaft 31. This "retracting" design not only prevents the STM probe 23 from blocking the electron beam, but also prevents the high-energy electron beam from directly bombarding the probe tip, causing contamination or passivation. When in STM mode, the STM probe 23 extends out of the composite shielding structure under the control of the upper drive shaft 31. The composite shielding structure and the rotatable sample holder 11 form a relatively closed electron beam shielding cavity, which greatly reduces the interference of stray electrons and lens magnetic field.

[0039] An in-situ preamplifier 24 is located immediately behind the STM probe 23. It is used to amplify the weak tunneling current signal in the picoampere (pA) to nanoampere (nA) range directly in a vacuum environment, and then transmit it to the outside through the sample rod body via a shielded wire.

[0040] like Figure 2 As shown, the sample rod head 1 has a through hole, and a rotatable sample holder 11 is built into the through hole. The structure of the rotatable sample holder 11 is as follows. Figure 9As shown, the overall structure is a plate-like structure with gradually increasing thickness from front to back, with holes for transmitting electron beams. The front and rear ends of the rotatable sample holder 11 are provided with wedge-shaped force-bearing structures, and both the front and rear wedge-shaped force-bearing structures have fixing slots (only the fixing slot at the front end is marked "Fixing Slot 14" for illustrative purposes). The rotatable sample holder 11 is positioned in front of the STM probe 23, and its rear end is movably connected to the sample rod head 1 via a flexible rotating hinge 12 (or a rotating shaft mechanism), and can rotate 90° around the flexible rotating hinge 12 (or rotating shaft mechanism). This flexible rotating hinge 12 (or rotating shaft mechanism) is perpendicular to the sample rod axis. When the sample holder is in TEM mode, the sample surface on the rotatable sample holder 11 is perpendicular to the TEM electron beam, and the position of the rotatable sample holder 11 at this time is defined as the first position; when the sample holder is in STM mode, the sample surface on the rotatable sample holder 11 is parallel to the TEM electron beam and perpendicular to the tip of the STM probe 23, and the position of the rotatable sample holder 11 at this time is defined as the second position; the rotatable sample holder 11 is flipped 90° between the first position and the second position through a linear-rotation conversion drive mechanism.

[0041] The linear-rotation conversion drive mechanism is connected to the back of the rotatable sample holder 11, such as... Figure 3 , Figure 4 and Figure 7 As shown, it includes a Y-shaped drive slider 15 and a lower drive shaft 32. A spatial rectangular coordinate system is established with the center point of the flexible rotary hinge 12 as point O, where the Z-axis is along the axial direction of the sample rod, the X-axis is along the direction of the flexible rotary hinge 12, that is, the XOZ plane is parallel to the rotatable sample holder 11, and the Y-axis is perpendicular to the XOZ plane. The linear-rotation conversion drive mechanism is used to convert the displacement of the Y-shaped drive slider 15 along the Z-axis into the angular displacement that drives the rotatable sample holder 11 to rotate around the X-axis. The lower drive shaft 32 is connected to the Y-type drive slider 15 and is used to push the Y-type drive slider 15 from the retracted position to the extreme position along the Z-axis. The front end of the Y-type drive slider 15 is provided with an upwardly protruding wedge-shaped force-applying structure. The inner wall of the through hole of the sample rod head 1 is provided with a guide rail parallel to the axial direction. The wedge-shaped force-applying structure can cooperate with the guide rail and the wedge-shaped force-receiving structure on the back of the rotatable sample holder 11. The wedge-shaped force-applying structure is provided with a locking pin 16. The extreme position of the Y-type drive slider 15 is the position of the Y-type drive slider 15 when the locking pin 16 is locked with the fixing slot 14. The retracted position of the Y-type drive slider 15 is the position of the Y-type drive slider 15 when the locking pin 16 is locked with the fixing slot at the rear end of the back of the rotatable sample holder 11. This design uses mechanical interlocking to ensure a repeatability accuracy better than ±0.1°.

[0042] The automatic electrical contact assembly includes a first contact 13, a second contact 17, and a conductive return spring 18, such as... Figure 2, Figure 8 and Figure 9 The first contact 13 is disposed on the rear end face of the rotatable sample holder 11, the second contact 17 is disposed on the fixed end face of the rotatable sample holder 11 and the sample rod head 1, and the conductive reset spring 18 is disposed at the second contact 17 or is the second contact 17 itself.

[0043] When the Y-shaped drive slider 15 is at its limit position, the locking pin 16 is inserted into the fixed slot 14, thereby locking the rotatable sample holder 11 in the first position. At this time, the first contact 13 and the second contact 17 are not closed, and the conductive reset spring 18 is in a relaxed state. When the Y-shaped drive slider 15 moves backward along the Z-axis, the wedge-shaped force-applying structure and the wedge-shaped force-receiving structure at the front end of the rotatable sample holder 11 release and cooperate. During the backward movement, the wedge-shaped force-applying structure pushes the rotatable sample holder 11 to gradually flip to the second position. At this time, the first contact 13 and the second contact 17 are tightly closed, grounding the sample to form a potential difference, thereby forming a tunneling current loop, effectively eliminating the electron beam-induced charging effect. At the same time, the conductive reset spring 18 is in a compressed state. When the Y-shaped drive slider 15 moves forward along the Z-axis again, the rotatable sample holder 11 gradually flips back to the first position under the power of the conductive reset spring 18.

[0044] like Figure 6 As shown, the front end of the handle 4 is provided with a guide positioning sheath 43 for precise positioning during the insertion and removal of the sample rod; the handle 4 is equipped with a stepper motor and a multi-position clutch. The stepper motor is connected to the upper drive shaft 31 and the lower drive shaft 32 and provides driving force to the upper drive shaft 31 and the lower drive shaft 32. The multi-position clutch realizes the power on / off and gear switching between the upper drive shaft 31 and the lower drive shaft 32; the front thin rod 2 and the rear thick rod 3 are connected by a vacuum sealing ring 33 to provide vacuum crossing boundary.

[0045] The STM probe assembly also includes a probe driving system, which includes a coarse adjustment module and a scanning module. The coarse adjustment module uses a stepper motor drive mechanism to drive the STM probe 23 to perform a large-range feed along the Z-axis, achieving a micrometer-level initial approximation between the STM probe 23 and the sample, and maintaining position self-locking in the power-off state. The scanning module drives the STM probe 23 to perform sub-nanometer-level fine displacement in the three orthogonal directions of X, Y, and Z through a piezoelectric ceramic tube to control the tunneling distance and perform grating scanning.

[0046] The present invention also provides an in-situ detection method for an in-situ transmission electron microscope sample rod based on the aforementioned integrated scanning tunneling microscope, the method being used to detect the bulk information or surface information of the sample; When it is necessary to detect the bulk information of a sample, the following steps are included: S1. Select the TEM position using the multi-position clutch inside the handle 4. Drive the stepper motor to push the Y-type drive slider 15 forward along the Z-axis. When the locking pin 16 of the wedge-shaped force-applying structure on the Y-type drive slider 15 is unlocked from the fixing slot of the wedge-shaped force-receiving structure at the rear end of the rotatable sample holder 11, the rotatable sample holder 11 gradually flips downward to the first position under the power of the conductive reset spring 18. When the Y-type drive slider 15 moves forward to the limit position, the locking pin 16 of the wedge-shaped force-applying structure on the Y-type drive slider 15 locks with the fixing slot 14 of the wedge-shaped force-receiving structure at the front end of the rotatable sample holder 11, forcibly locking the rotatable sample holder 11 mechanically to the first position. At this time, the sample plane is perpendicular to the electron beam.

[0047] S2. Power is switched to the upper drive shaft 31 via a multi-gear clutch, and the upper drive shaft drives the STM probe 23 to retract into the composite shielding structure.

[0048] S3. Start the electron source of the in-situ transmission electron microscope to emit an electron beam, perform imaging or diffraction analysis of the sample, and obtain the sample bulk information.

[0049] When it is necessary to detect information on the surface of a sample, the following steps are included: 1) Select the STM gear by using the multi-position clutch in the handle 4. The stepper motor drives the drive shaft 32 to push the Y-type drive slider 15 back along the Z-axis, releasing the lock on the fixed slot 14. During the retraction of the Y-type drive slider 15, the wedge-shaped force-applying structure pushes the rotatable sample holder 11 to gradually rotate upward 90° around the X-axis to the second position. At this time, the first contact 13 and the second contact 17 are tightly closed (or the first contact 13 directly presses the conductive spring 18), directly connecting the sample to the system ground, effectively discharging the accumulated charge and eliminating the charging effect.

[0050] 2) Power is switched to the upper drive shaft 31 via a multi-speed clutch. The upper drive shaft drives the STM probe 23 to extend from the composite shielding structure, which works with the piezoelectric ceramic tube to perform coarse-tuning approximation and fine scanning of the sample. At this time, the upright rotatable sample holder 11 and the composite shielding structure form a physical electron beam blocking cavity, minimizing background noise.

[0051] 3) The current feedback loop of the scanning tunneling microscope is activated to establish a stable tunneling current, and then the grating scanning is started. The STM probe 23 collects the weak tunneling current in the picoampere (pA) to nanoampere (nA) range and directly transmits it to the in-situ preamplifier 24 adjacent to the STM probe 23 for signal amplification. Then, the sample rod is transmitted through the shielded wire to obtain the sample surface information.

[0052] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An in-situ transmission electron microscope sample holder for an integrated scanning tunneling microscope, characterized in that, include: The sample rod body includes a handle, a thicker rear rod, a thinner front rod, and a sample rod head connected in sequence. The STM probe assembly includes an STM probe and an upper drive shaft. The front end of the front thin rod has a mounting groove, in which the STM probe is placed. The tip of the STM probe points parallel to the axial direction of the sample rod body. The rear end of the STM probe is connected to the upper drive shaft, which is used to control the linear feed motion of the STM probe. A rotatable sample holder is set inside the sample rod head and hinged to the sample rod head at the rear end. In TEM mode, the sample surface on the rotatable sample holder is perpendicular to the TEM electron beam, and the position of the rotatable sample holder at this time is defined as the first position. In STM mode, the sample surface is parallel to the TEM electron beam and perpendicular to the tip of the STM probe, and the position of the rotatable sample holder at this time is defined as the second position. A linear-rotation conversion drive mechanism is connected to the back of the rotatable sample holder and is used to convert the linear displacement of the linear-rotation conversion drive mechanism along the sample rod axis into the angular displacement of the rotatable sample holder about the hinge, thereby causing the rotatable sample holder to flip in place between the first position and the second position. An automatic electrical contact assembly includes a first contact disposed on the rear end face of a rotatable sample holder and a second contact disposed on the fixed end face of a sample rod head; in STM scanning mode, the first contact and the second contact close to ground the sample to form a potential difference, thereby forming a tunneling current loop.

2. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 1, characterized in that, The STM probe assembly also includes a composite shielding structure, comprising a magnetic shielding coating and an electrostatic shielding shell that are coaxially wrapped around the outside of the STM probe from the inside out; in TEM mode, the STM probe retracts into the composite shielding structure under the control of the upper drive shaft to prevent the STM probe from blocking the electron beam. In STM mode, the STM probe extends out of the composite shielding structure under the control of the upper drive shaft. The composite shielding structure and the rotatable sample holder located in the second position form a relatively closed electron beam shielding cavity, which is used to block the interference of the main electron beam of the transmission electron microscope and secondary scattered electrons on the tip of the STM probe.

3. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 1, characterized in that, The rotatable sample holder is a plate-shaped structure with a thickness that gradually increases from front to back, and it has holes for transmitting electron beams; the front and rear ends of the back of the rotatable sample holder are provided with wedge-shaped force-bearing structures, and the wedge-shaped force-bearing structures at the front and rear ends are provided with fixing slots.

4. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 1, characterized in that, The rotatable sample holder and the sample rod head are hinged together by a flexible rotary hinge or a rotating shaft mechanism.

5. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 3, characterized in that, The linear-rotation conversion drive mechanism includes a Y-shaped drive slider and a lower drive shaft; the lower drive shaft is connected to the rear end of the Y-shaped drive slider and is used to drive the Y-shaped drive slider forward or backward; the front end of the Y-shaped drive slider is provided with an upwardly protruding wedge-shaped force-applying structure, which can cooperate with the wedge-shaped force-receiving structure on the back of the rotatable sample holder, and drives the rotatable sample holder to flip upward when the Y-shaped drive slider retracts. The wedge-shaped force-applying structure is equipped with a locking pin, which is used to lock the rotatable sample holder in place with the fixing slot on the back of the rotatable sample holder.

6. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 5, characterized in that, The sample rod head is provided with a through hole, and a rotatable sample holder is built into the through hole; a guide rail parallel to the axial direction of the sample rod is provided on the lower part of the inner wall of the through hole, and the wedge-shaped force application structure at the front end of the Y-shaped drive slider is locked on the guide rail to move forward or backward.

7. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 5, characterized in that, The automatic electrical contact assembly also includes a conductive reset spring, disposed at the second contact or as the second contact itself; in STM mode, the conductive reset spring is compressed to provide elastic contact force to ensure low-resistance grounding. When switching from STM mode to TEM mode, the conductive reset spring releases elastic potential energy to assist in the reset and flipping of the rotatable sample holder.

8. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 1, characterized in that, It also includes an in-situ preamplifier, which is located inside the front end rod and adjacent to the rear end of the STM probe, for directly amplifying nanoampere-level tunneling current signals in a vacuum environment.

9. The in-situ transmission electron microscope sample holder of the integrated scanning tunneling microscope according to claim 1, characterized in that, The handle is equipped with a stepper motor and a multi-gear clutch. The stepper motor is connected to the upper drive shaft and the linear-rotation conversion drive mechanism, and provides driving force to the upper drive shaft and the linear-rotation conversion drive mechanism. The multi-gear clutch realizes the power on / off and gear switching between the upper drive shaft and the linear-rotation conversion drive mechanism.

10. A method for detecting an in-situ transmission electron microscope sample rod based on the integrated scanning tunneling microscope of claim 7, characterized in that, The method is used to detect the bulk or surface information of a sample; When it is necessary to detect the bulk information of a sample, the following steps are included: S1. The lower drive shaft pushes the Y-type drive slider forward. When the locking pin on the Y-type drive slider is unlocked from the fixed slot at the rear end of the rotatable sample holder, the rotatable sample holder gradually flips downward to the first position under the power of the conductive reset spring. The Y-type drive slider moves forward until the locking pin locks with the fixed slot at the front end of the rotatable sample holder, forcibly locking the rotatable sample holder mechanically to the first position. At this time, the sample plane is perpendicular to the electron beam. S2. The upper drive shaft drives the STM probe to retract into the composite shielding structure. S3. Start the electron source of the in-situ transmission electron microscope to emit an electron beam, perform imaging or diffraction analysis and detection of the sample, and obtain the sample bulk information. When it is necessary to detect information on the surface of a sample, the following steps are included: 1) The lower drive shaft pushes the Y-type drive slider backward to release the lock on the fixed slot at the front end of the rotatable sample holder. During the backward movement of the Y-type drive slider, the retraction of the wedge-shaped force structure drives the rotatable sample holder to gradually rotate upward 90° to the second position. At this time, the first contact and the second contact are tightly closed, directly connecting the sample to the system ground, effectively discharging the accumulated charge and eliminating the charging effect. 2) The upper drive shaft drives the STM probe to extend out of the composite shielding structure. At this time, the rotatable sample holder and the composite shielding structure form an electron beam blocking cavity, which reduces background noise. 3) Activate the current feedback loop of the scanning tunneling microscope to establish a stable tunneling current, then start the grating scan, the STM probe collects the tunneling current signal and transmits it to the sample rod to obtain sample surface information.

Images