Low-temperature strain sample and photoelectric characteristic measuring device and measuring preparation method

Abstract

The invention relates to the technical field of photoelectric device measurement, in particular to a low-temperature strain sample photoelectric characteristic measuring device which comprises a low-temperature container unit, a sample unit and a measuring unit. The sample unit is mounted across the cryogenic vessel. And the measuring unit is arranged in the low-temperature container unit. In measurement, the sample unit and the measurement unit are in the same low-temperature environment. The sample unit is used for loading a sample and changing the mechanical characteristics of the sample in a low-temperature environment; when the sample has different mechanical characteristics, the measuring unit measures the optical and electrical characteristics of the sample at the same time. The invention further comprises a measuring method, a low-temperature strain sample matched with the device and a preparation method. According to the device, the temperature can be maintained at the liquid nitrogen temperature for more than 3 hours, in-situ photoelectric characteristic measurement under various strain modulations can be carried out during the period, and in-plane tensile strain is applied at low temperature while in-situ photoelectric characteristic characterization can be carried out on a sample.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric device measurement, in particular to a low-temperature strain sample and a photoelectric characteristic measurement device and a measurement preparation method. Background Art

[0002] Due to the current highly integrated electronic circuits, the demand for developing smaller semiconductor devices continues to grow. In recent years, functional devices based on low-dimensional materials have been demonstrated one after another. Their extremely small physical dimensions meet the needs of future highly integrated electronic circuits. Therefore, strain engineering of low-dimensional materials has become a research focus. Strain engineering, through the introduction of mechanical strain, can regulate the optoelectronic properties of low-dimensional materials and realize high-performance devices based on low-dimensional materials. The combination of strain engineering-based methods with low-dimensional optoelectronic devices has led to rapid development of research on flexible optoelectronic devices based on low-dimensional materials. And with this effective control method, low-dimensional materials have enabled people to explore novel physical effects that are different from those of bulk materials.

[0003] Currently, traditional strain engineering is limited to applying mechanical strain to samples at room temperature and measuring their optoelectronic properties in situ. However, many novel physical effects based on low-dimensional materials are shielded by temperature effects, making it difficult to clearly observe the effects of strain on these novel physical effects. Furthermore, in situ characterization of the optoelectronic properties of samples while applying strain at low temperatures is also a pressing need in this field. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-temperature strain sample and a photoelectric characteristic measurement device and a measurement preparation method, which mainly solve the problems existing in the above-mentioned prior art.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is to provide a low-temperature strain sample photoelectric characteristic measurement device, which is characterized by comprising a low-temperature container unit, a sample unit and a measurement unit;

[0006] The sample unit is installed across the low-temperature container; the measurement unit is installed in the low-temperature container unit; during measurement, the sample unit and the measurement unit are both in the same low-temperature environment; the sample unit is loaded with a sample and changes the mechanical characteristics of the sample in the low-temperature environment; when the sample is in a state of different mechanical characteristics, the measurement unit simultaneously measures the optical and electrical characteristics of the sample.

[0007] Furthermore, the low-temperature container unit includes a low-temperature Dewar container and a cold stage;

[0008] An infusion pipe joint and an evacuation valve are provided on the low-temperature Dewar container; the infusion pipe joint is connected to the interlayer of the low-temperature Dewar container and is used to introduce low-temperature liquid into the interlayer; the evacuation valve is connected to the interlayer of the low-temperature Dewar container and is used to evacuate the interlayer into a vacuum; the cold stage is made of heat-conducting metal and is installed in the low-temperature Dewar container; the sample unit is fitted on the cold stage.

[0009] Furthermore, the sample unit comprises a sample holder, a movable chuck and an adjuster;

[0010] The sample holder and the moving chuck are installed in the low-temperature container unit; the adjuster is connected to the moving chuck and installed across the low-temperature container unit;

[0011] The sample holder is made of heat-conducting metal and is fixed to the low-temperature container unit; two parallel guide rails are provided on the sample holder; the movable chuck is installed on the parallel guide rails and slides along the direction of the parallel guide rails under the drive of the regulator; a fixed slot is provided on each of the sample holder and the movable chuck; the two fixed slots cooperate with each other to clamp the sample.

[0012] Furthermore, the measurement unit includes an optical measurement channel and an electrical measurement channel; the optical measurement channel is a light-transmitting window opened on the low-temperature container unit and located above the sample unit; the electrical measurement channel is located inside the low-temperature container unit and connected to the sample unit.

[0013] Furthermore, the light-transmitting window is made of transparent quartz glass.

[0014] Furthermore, the electrical measurement channel includes a measurement line connector and a data line transition plate; the measurement line connector is installed through the low-temperature container unit; the data line transition plate is installed in the low-temperature container unit and is connected to the measurement line connector and the sample unit respectively.

[0015] The present invention also discloses a measurement method using the above-mentioned low-temperature strain sample photoelectric characteristic measurement device, which is characterized by comprising the steps of:

[0016] Step S101, installing the sample on the sample unit;

[0017] Step S102, establishing a low-temperature environment in the low-temperature container unit; evacuating the interlayer of the low-temperature container unit into a vacuum through an evacuation valve, and then inputting a low-temperature liquid into the low-temperature container unit through an infusion pipe joint;

[0018] Step S103, connecting the measuring line connector, and connecting the sample to the instrument via the data line transition board;

[0019] Step S104, turning on the light source and irradiating the sample through the light-transmitting window;

[0020] Step S105, measuring the electrical characteristics of the sample using the instrument;

[0021] Step S106, applying pressure to the sample using a regulator to change the mechanical characteristics of the sample;

[0022] Step S107: If the measurement is not completed, jump to step S105; otherwise, go to step S108;

[0023] Step S108: disconnect the instrument, turn off the light source, remove the sample, and the measurement is completed.

[0024] The present invention also discloses a low-temperature strain sample, which is used in conjunction with the above-mentioned low-temperature strain sample photoelectric characteristic measurement device, and is characterized in that it comprises a thermal conductive copper foil, a flexible substrate and a photoelectric material sheet;

[0025] The optoelectronic material sheet is stacked on the flexible substrate. The thermally conductive copper foil is wrapped around both ends of the flexible substrate. During measurement, the thermally conductive copper foil contacts the low-temperature strain-testing device for measuring optoelectronic properties of a sample. Under the pressure of the device, the flexible substrate deforms, causing the optoelectronic material sheet to deform synchronously.

[0026] Furthermore, the flexible substrate is made of silicon dioxide or mica.

[0027] The present invention also discloses a method for preparing the above-mentioned low-temperature strain sample, which is characterized by comprising the steps of:

[0028] Step S201, using an adhesive tape to peel off the photoelectric material, and obtaining the photoelectric material sheet on the surface of the adhesive tape;

[0029] Step S202, attaching the adhesive tape to the polymer, thereby transferring the photoelectric material sheet to the polymer; if the thickness of the photoelectric material sheet stacked on the polymer is not enough, skip to step S201, otherwise go to step S203;

[0030] Step S203, using a transfer device to transfer the optoelectronic material sheet stacked on the high molecular polymer to the flexible substrate;

[0031] Step S204 : Covering the two ends of the flexible substrate with the thermally conductive copper foil respectively.

[0032] In view of the above technical features, the present invention provides a low-temperature strain sample and photoelectric property measurement device and measurement preparation method, which can be used to study the photoelectric properties of materials under strain at low temperatures. This device uses optical means to perform in-situ spectral measurements through the measurement window, and connects the sample to a data line transition plate to perform in-situ electrical measurements. Compared with existing technologies, this invention has the following advantages:

[0033] 1. The present invention can maintain the temperature at liquid nitrogen temperature for more than 3 hours, during which time in-situ photoelectric property measurements under various strain modulations can be performed.

[0034] 2. The present invention achieves the in-situ characterization of the photoelectric properties of the sample while applying in-plane tensile strain at low temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of a preferred embodiment of the low-temperature strain sample and photoelectric characteristic measurement device of the present invention;

[0036] Figure 2 This is a partial enlarged view of a sample holder in a preferred embodiment of the low-temperature strain sample and photoelectric characteristic measurement device of the present invention;

[0037] Figure 3 This is a measurement schematic diagram of a preferred embodiment of the low-temperature strain sample and photoelectric characteristic measurement device of the present invention;

[0038] Figure 4 This is a method flow chart of a preferred embodiment of the measurement method of the present invention using a low-temperature strain sample and a photoelectric characteristic measurement device (spectral and electrical characteristics are obtained together);

[0039] Figure 5 This is the measurement result of a preferred embodiment of the measurement method of the present invention using a low-temperature strain sample and a photoelectric characteristic measurement device;

[0040] Figure 6 This is another measurement result of a preferred embodiment of the measurement method of the present invention using a low-temperature strain sample and a photoelectric characteristic measurement device;

[0041] Figure 7 Schematic diagram of the structure of a preferred embodiment of the low-temperature strain sample of the present invention;

[0042] Figure 8 This is a flow chart of a preferred embodiment of the method for preparing a low-temperature strain sample of the present invention.

[0043] In the figure: 1- low-temperature Dewar container, 2- evacuation valve, 3- infusion pipe connector, 4- measuring line connector, 5- cold stage, 6- measuring window, 7- sample holder, 8- regulator, 9- data line transition plate, 10- movable chuck, 11- fixed card slot, 12- thermal conductive copper foil, 13- flexible substrate, 14- photoelectric thin film material, 15- external light source. DETAILED DESCRIPTION

[0044] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0045] See also Figure 1 、 Figure 2 and Figure 3 The present invention discloses a photoelectric characteristic measurement device for measuring the photoelectric characteristics of a low-temperature strain sample. As shown in the figure, a preferred embodiment thereof includes a low-temperature container unit, a sample unit, and a measurement unit.

[0046] The cryogenic container unit consists of a cryogenic Dewar vessel 1 and a cold stage 5. The cryogenic Dewar vessel 1 is a highly sealed stainless steel container with an interlayer. It has three interfaces: an evacuation valve 2, a liquid infusion pipe connector 3, and a measurement line connector 4. The evacuation valve 2 connects the interlayer of the cryogenic Dewar vessel 1 to the outside world. When closed, the evacuation valve 2 maintains a high vacuum within the interlayer of the cryogenic Dewar vessel 1. Before measurement, the evacuation valve 2 is used to evacuate the interlayer, effectively reducing heat transfer between the interior of the cryogenic Dewar vessel 1 and the outside world. The liquid infusion pipe connector 3 also connects the outside world to the interlayer of the cryogenic Dewar vessel 1. During measurement, cryogenic liquid, such as liquid nitrogen, is injected into the evacuated interlayer of the cryogenic Dewar vessel 1 through the liquid infusion pipe connector 3, thereby reducing the temperature inside the cryogenic Dewar vessel 1. The cold stage 5, made of copper, is installed within the cryogenic Dewar vessel 1. The sample unit, which holds the sample to be measured, is mounted snugly on the cold stage 5.

[0047] The sample unit consists of a sample holder 7, an adjuster 8 and a movable chuck 10. The sample holder 7 and the movable chuck 10 are installed in a low-temperature Dewar container 1 and are in a low-temperature environment. The adjuster 8 is installed across the low-temperature Dewar container 1, with one end connected to the movable chuck 10 and the other end outside the low-temperature Dewar container 1. It is used to adjust the force applied to the sample outside the low-temperature Dewar container 1 during the measurement process. The sample holder 7, like the cold stage 5, is made of heat-conducting metal. In this embodiment, the sample holder 7 is made of copper. The sample holder 7 is installed in contact with the cold stage 5 so that the heat of the sample can be quickly transferred away, ensuring that the sample remains at a low temperature during the measurement process. The movable chuck 10 is installed on the sample holder 7. Specifically, two parallel guide rails are provided on the sample holder 7, and the movable chuck 10 is installed on the parallel guide rails. One end of the movable chuck 10 is connected to the adjuster 8.

[0048] When the other end of the regulator 8 is externally rotated, the regulator 8 pushes one end of the movable chuck 10 by torsional precession, pushing the movable chuck 10 to slide along the parallel guide rail, thereby changing the distance between the movable chuck 10 and the sample holder 7. A fixed slot 11 is provided on each of the sample holder 7 and the movable chuck 10. The two fixed slots 11 are opposite each other and cooperate with each other to clamp the sample during measurement. When the distance between the sample holder 7 and the movable chuck 10 changes, different in-plane tensile stresses can be applied to the sample, thereby changing the mechanical characteristics of the sample and facilitating the detection of photoelectric properties under different mechanical characteristics.

[0049] The measurement unit is used to measure the photoelectric properties of the sample. Therefore, it comprises two measurement channels: an optical measurement channel and an electrical measurement channel. The optical measurement channel is a light-transmitting window opened in the cryogenic Dewar vessel 1. Made of transparent quartz glass, it allows light of multiple wavelengths to pass through the sample, facilitating in-situ spectral characterization of the sample. The light-transmitting window is located above the sample holder 7 and the movable chuck 10. During measurement, an external light source 15 illuminates the sample through the light-transmitting window. The electrical measurement channel, located within the cryogenic Dewar vessel 1, comprises a measurement line connector 4 and a data line transition plate 9. The measurement line connector 4 is installed across the cryogenic Dewar vessel 1, while the data line transition plate 9 is fixed to the sample holder 7 and directly connects to both sides of the sample mounted on the sample holder 7 to collect the sample's electrical characteristics. The data line transition plate 9 also contains lead wires that connect to the measurement line connector 4. The built-in data line transition plate 9 facilitates soldering of the sample's electrical circuits. Therefore, during measurement, an external device only needs to make an electrical connection to the measurement line connector 4 to obtain the sample's electrical signal across the cryogenic Dewar vessel 1 and evaluate its electrical properties. At the same time, the sample and the data line transition plate 9 are both located in the same low-temperature environment, which facilitates eliminating the temperature interference of the measurement unit on the sample.

[0050] See also Figure 4The present invention also discloses a method for measuring the photoelectric characteristics of a low-temperature strain sample using the above-mentioned device. A preferred embodiment thereof comprises the steps of:

[0051] Step S11, installing the sample.

[0052] Place the sample on the sample holder. Align the ends of the sample with the movable chuck and the fixed slots of the sample holder. Then, use the adjuster to adjust the distance between the movable chuck and the sample holder so that the sample is clamped between the movable chuck and the sample holder by the fixed slots.

[0053] Step S12: establishing a low-temperature environment.

[0054] The interlayer is evacuated to a vacuum through the evacuation valve of the low-temperature Dewar container. Specifically, a mechanical pump is used to evacuate the vacuum to a negative pressure of 5×10 -2 Torr, and then use a molecular pump to evacuate to a negative pressure of 5×10 -5 Torr, close the evacuation valve and then turn off the molecular pump.

[0055] Then, liquid nitrogen is input into the barrier of the low-temperature Dewar container through the liquid infusion pipe joint until the liquid nitrogen overflows from the liquid infusion pipe joint, thereby establishing a low-temperature environment inside the low-temperature Dewar container.

[0056] Step S13: connecting the electrical measurement channel.

[0057] Use the measurement line connector on the low-temperature Dewar container to connect the external measuring instrument to the sample through the data line transition board.

[0058] Step S14: connecting the optical measurement channel.

[0059] Turn on the laser light source so that the light shines onto the sample through the light-transmitting window set on the low-temperature Dewar container, thereby stimulating the photoelectric effect during measurement.

[0060] Step S15: reading electrical characteristics.

[0061] External instruments are used to measure and record the electrical properties of the sample under current mechanical characteristics and lighting conditions, and micro-area microspectroscopy technology is used for in-situ spectral characterization.

[0062] Step S16, changing the mechanical properties of the sample.

[0063] The adjuster is used to shorten the distance between the moving chuck and the sample holder, thereby squeezing the sample and causing it to bend under pressure to generate tensile strain, thereby changing the mechanical characteristics of the sample.

[0064] In step S17, if the measurement is not completed, the process goes to step S15 to measure the electrical and spectral characteristics under different mechanical characteristics. If the measurement is completed, the process goes to step S18.

[0065] Step S18: obtaining the measurement result.

[0066] Disconnect the instrument, turn off the light source, open the low-temperature Dewar container and remove the sample, and the measurement of the sample is completed. Figure 5 and Figure 6 shown.

[0067] See also Figure 7 In order to cooperate with the low-temperature strain sample photoelectric property measurement device, the material to be measured needs to be made into a sample. Therefore, the present invention also discloses a low-temperature strain sample for the above-mentioned low-temperature strain sample photoelectric property measurement device. A preferred embodiment thereof includes a thermally conductive copper foil 12, a flexible substrate 13 and a photoelectric material sheet 14. The photoelectric material sheet 14 is a sheet structure of low-temperature heterojunction material, which is stacked on the flexible substrate 13. The thermally conductive copper foil 12 is coated on both ends of the flexible substrate 13. The flexible substrate 13 is made of silicon dioxide or mica (the flexible substrate is mica, and a layer of 100nm silicon dioxide is deposited on the mica). Its size corresponds to the size of the sample holder 7, and in particular, the thickness of the flexible substrate 13 corresponds to the thickness of the fixed card slot 11 on the sample holder 7 and the movable chuck 10, so that the low-temperature strain sample can be firmly clamped. During measurement, the thermally conductive copper foil 12 contacts the copper sample holder 7 and the movable chuck 10, thereby quickly conducting the heat away from the low-temperature strain sample. When the adjuster 8 is activated to reduce the distance between the sample holder 7 and the movable chuck 10 , the flexible substrate 13 is deformed, causing the photovoltaic material sheet 14 covering it to deform synchronously, thereby changing the mechanical properties of the low-temperature heterojunction material.

[0068] See also Figure 8 The present invention also discloses a method for preparing the above-mentioned low-temperature strain sample. A preferred embodiment thereof comprises the steps of:

[0069] Step S21: obtaining a photoelectric material sheet.

[0070] Use blue film tape to peel off photovoltaic materials, such as WS2 (MoSe2) bulk materials, to obtain photovoltaic material flakes on the surface of the tape.

[0071] Step S22 , transferring the photoelectric material sheet onto the high molecular polymer (PMDS).

[0072] The blue film tape with the sample evenly distributed is pasted on the PMDS. The single layer sample is searched on the PMDS. If no single layer sample is found, the process jumps to step S21, otherwise, the process goes to step S23.

[0073] Step S23: transferring the optoelectronic material sheet onto the flexible substrate.

[0074] Use a transfer device to transfer stacked photovoltaic material sheets to a flexible substrate. Align the smooth, fractured long edges of the samples during transfer. Ensure the twist angle error between the two is within 5 degrees.

[0075] Step S24: covering with thermally conductive copper foil.

[0076] Thermally conductive copper foils are respectively coated on both ends of the flexible substrate to form a low-temperature strain sample to be measured.

[0077] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for measuring photoelectric properties of low temperature strain samples, characterized in that: It includes a low temperature container unit, a sample unit and a measuring unit; The sample unit is installed across the low-temperature container; the measuring unit is installed in the low-temperature container unit; during measurement, the sample unit and the measuring unit are both in the same low-temperature environment; the sample unit is loaded with a sample and changes the mechanical characteristics of the sample in the low-temperature environment; when the sample is in a state of different mechanical characteristics, the measuring unit simultaneously measures the optical and electrical characteristics of the sample.

2. The low temperature strain sample photoelectric property measurement device according to claim 1, characterized in that: The low temperature container unit comprises a low temperature Dewar container and a cold stage; An infusion pipe joint and an evacuation valve are provided on the cryogenic Dewar container; the infusion pipe joint is connected to the interlayer of the cryogenic Dewar container and is used to introduce cryogenic liquid into the interlayer; the evacuation valve is connected to the interlayer of the cryogenic Dewar container and is used to evacuate the interlayer; The cold stage is made of heat-conducting metal and is installed in the low-temperature Dewar container; the sample unit is fitted and installed on the cold stage.

3. The low temperature strain sample photoelectric property measurement device according to claim 1, characterized in that: The sample unit comprises a sample holder, a movable chuck and an adjuster; The sample holder and the moving chuck are installed in the low temperature container unit; the regulator is connected to the moving chuck and installed across the low temperature container unit; The sample holder is made of heat-conducting metal and is fixed on the low-temperature container unit; two parallel guide rails are arranged on the sample holder; the movable chuck is installed on the parallel guide rails and slides along the direction of the parallel guide rails under the drive of the regulator; a fixed card slot is arranged on the sample holder and the movable chuck respectively; the two fixed card slots cooperate with each other to clamp the sample.

4. The low temperature strain sample photoelectric property measurement device according to claim 1, characterized in that: The measuring unit comprises an optical measuring channel and an electrical measuring channel; the optical measuring channel is a light-transmitting window opened on the low-temperature container unit and located above the sample unit; the electrical measuring channel is located in the low-temperature container unit and connected to the sample unit.

5. The low temperature strain sample photoelectric property measurement device according to claim 4, characterized in that: The light-transmitting window is made of transparent quartz glass.

6. The low temperature strain sample photoelectric property measurement device according to claim 4, characterized in that: The electrical measurement channel comprises a measurement line connector and a data line transition plate; the measurement line connector is installed through the low temperature container unit; the data line transition plate is installed in the low temperature container unit and is respectively connected to the measurement line connector and the sample unit.

7. A measurement method using the low temperature strain sample photoelectric property measurement device as claimed in claim 1, characterized in that: Contains steps: Step S101, installing the sample on the sample unit; Step S102, establishing a low-temperature environment in the low-temperature container unit; evacuating the interlayer of the low-temperature container unit into a vacuum through an evacuation valve, and then inputting a low-temperature liquid into the low-temperature container unit through an infusion pipe joint; Step S103, connecting the measuring line connector, and connecting the sample to the instrument through the data line transition board; Step S104, turning on the light source and irradiating the light onto the sample through the light-transmitting window; Step S105, measuring the electrical characteristics of the sample from the instrument; Step S106, applying pressure to the sample using a regulator to change the mechanical characteristics of the sample; Step S107, if the measurement is not completed, jump to step S105, otherwise go to step S108; Step S108, disconnect the instrument, turn off the light source, remove the sample, and the measurement is completed.

8. A low temperature strain sample, used in conjunction with the low temperature strain sample photoelectric property measurement device as claimed in claim 1, characterized in that: Contains thermally conductive copper foil, flexible substrate and optoelectronic material sheets; The optoelectronic material sheet is stacked on the flexible substrate; The two ends of the flexible substrate are coated with the thermal conductive copper foil; During measurement, the thermally conductive copper foil contacts the low temperature strain sample photoelectric characteristic measuring device. Under the pressure of the low temperature strain sample photoelectric characteristic measuring device, the flexible substrate deforms, driving the photoelectric material sheet to deform synchronously.

9. The low temperature strain sample according to claim 8, characterized in that: The flexible substrate is made of silicon dioxide or mica.

10. A method for preparing a low temperature strain sample as claimed in claim 8, characterized in that: Contains steps, Step S201, using an adhesive tape to peel off the photoelectric material, and obtaining the photoelectric material sheet on the surface of the adhesive tape; Step S202, sticking the adhesive tape onto the polymer, thereby transferring the photoelectric material sheet onto the polymer; if the thickness of the photoelectric material sheet stacked on the polymer is not enough, jump to step S201, otherwise go to step S203; Step S203, using a transfer device to transfer the optoelectronic material sheet stacked on the high molecular polymer to the flexible substrate; Step S204 , respectively covering the two ends of the flexible substrate with the thermally conductive copper foil.

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