A method for realizing multi-parameter photoelectric detection based on CrSBr tunneling structure

Abstract

The application discloses a method for realizing multi-parameter photoelectric detection based on a CrSBr tunneling structure. The method utilizes the spin-electron coupling effect in a two-dimensional antiferromagnetic semiconductor CrSBr. By applying light with different photon energies and polarization degrees to the tunneling structure, a stable and high linear dichroism photoelectric current response can be obtained, and the photoelectric current response is effectively controlled by a magnetic field, so that multi-parameter photoelectric detection is realized. The application provides an important material platform and research foundation for researching a new generation of spin-electron-optoelectronic devices and sensitive multi-field sensors.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spintronics and optoelectronic detection devices, and in particular to a method for detecting various external physical parameters (including photon energy, light polarization and magnetic field) by using a two-dimensional magnetic semiconductor CrSBr tunnel junction and through light excitation and external magnetic field regulation. BACKGROUND

[0002] With the continuous progress of information technology, chip miniaturization has gradually entered the post-moore era. Exploring and utilizing new degrees of freedom and information transmission methods provides new opportunities for the innovation of the next generation of electronic devices. Since the discovery of graphene, low-dimensional van der Waals material systems have attracted widespread attention in both basic physical research and electronic device applications. Two-dimensional semiconductor materials have become one of the key materials for the preparation of various electronic and optoelectronic devices due to their tunable band gap and high carrier mobility.

[0003] However, current optoelectronic detection technologies based on traditional semiconductors have many limitations in multi-parameter regulation. In particular, the intrinsic band structure of these materials is not sensitive to the response of the applied magnetic field, resulting in the need for complex heterostructures or the introduction of defects for the magnetic field regulation of most optoelectronic devices. This increases the complexity of the system and reduces its operability in practical applications. In addition, existing technologies usually require a strong magnetic field to produce significant optoelectronic effect regulation, further limiting the stability and application range of these devices. Therefore, developing efficient, magnetic field adjustable, multi-degree of freedom coupled optoelectronic materials and optoelectronic devices has become an important and challenging task in the field of spintronics and optoelectronics. SUMMARY

[0004] To solve the problems existing in the prior art, the present application provides a method for realizing multi-parameter optoelectronic detection based on a CrSBr tunnel structure, which utilizes a two-dimensional antiferromagnetic semiconductor material CrSBr to realize the synergistic regulation of the optoelectronic performance of the magnetic field and the photon energy and polarization degree, providing an important platform for exploring the interaction between magnetic, optical and electrical characteristics.

[0005] In order to achieve the purpose of the present application, the present application provides a method for realizing multi-parameter optoelectronic detection based on a CrSBr material tunnel structure, comprising the following specific steps:

[0006] 1) A graphite material, a CrSBr material and a graphite material are sequentially placed on a pre-prepared electrode Si / SiO2 substrate by a dry transfer method to obtain a tunnel junction device;

[0007] 2) The tunnel junction device is cooled to 2K, a specific voltage is applied to the tunnel junction device, the incident photon energy and power are changed based on the variable wavelength supercontinuum laser, the photocurrent size and photoresponsivity with the incident photon energy at the voltage are obtained, and a photocurrent-photon energy spectrum is obtained;

[0008] 3) The polarization angle of the incident light is changed, the "8" figure distribution of the photocurrent with the incident light polarization angle in step 2) is measured, the maximum value is along the b axis of the CrSBr material lattice, the minimum value is along the a axis of the CrSBr material lattice, and the photoresponse spectrum of the photocurrent is obtained by dividing the photocurrent-photon energy spectrum of the incident light polarized in the two maximum value directions;

[0009] 4) The incident photon polarization is fixed at the angle along the b axis of the CrSBr material crystal, the applied magnetic field and the photon energy are changed, and a magnetic field-photon energy photocurrent response phase diagram is obtained.

[0010] Further, the thickness of the CrSBr material in step 1) is 20-100 nm, and the thickness of the graphite material is within 10 nm.

[0011] Further, in step 2), the specific voltage is 2.7V, the incident photon energy is 1.3-1.9eV, and the incident photon power is 0-20μW.

[0012] Further, in step 3), a polarizer and a 1 / 2 wave plate are added in the excitation light path to change the polarization angle of the incident light.

[0013] Further, in step 3), a 1 / 4 wave plate is used to change the optical rotation characteristics of the incident light, and the photocurrent difference under the excitation of left-handed and right-handed photons is obtained.

[0014] Further, in step 4), the applied magnetic field is from 0 to 3T, and the photon energy is from 1.30eV to 1.45eV. The magnetic field is along the spin jump a axis or b axis of the CrSBr material, or the magnetic field is along the spin tilt c axis of the CrSBr material.

[0015] Further, a pA-precision ammeter is used to measure the tunnel junction device.

[0016] Further, an electrostatic shield is arranged on the detection area of the tunnel junction device to avoid the current change caused by environmental noise.

[0017] The technical advantages of the present application mainly include the following points:

[0018] 1) The intrinsic van der Waals magnetic semiconductor CrSBr used in the present invention is an antiferromagnetic direct bandgap semiconductor with a high transition temperature (132K). Its unique spin-electron coupling effect makes it extremely sensitive to external magnetic fields. At the same time, CrSBr has strong optical absorption anisotropy. Compared with other semiconductor materials, the two-dimensional magnetic semiconductor CrSBr has an intrinsic magneto-optical coupling effect, which can realize multi-parameter photoelectric detection.

[0019] 2) The present invention utilizes the extremely stable and high polarization ratio anisotropy of the band structure of CrSBr to flexibly adjust the photocurrent response under various external fields (magnetic field, light field and voltage) to achieve multi-parameter photoelectric detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a schematic diagram of the tunnel junction device of the present invention.

[0021] Figure 2 Optical photograph of the tunnel junction device of the present invention.

[0022] Figure 3 The photocurrent-photon energy spectrum of the tunnel junction in the specific embodiment of the present invention shown in the figure is obtained when the incident light is polarized along the b-axis and a-axis of CrSBr at a bias voltage of 2.7V, and a linear dichroism ratio of nearly 60 is obtained under the excitation of 1.376eV incident photons.

[0023] Figure 4 The curve of the photocurrent-photon energy spectrum changing with the external magnetic field in the specific embodiment of the present invention is shown, and the photocurrent peak value and response degree that can be adjusted by the external magnetic field are obtained.

[0024] Figure 5 The figure shows the synchronous evolution of the tunnel junction photocurrent with the external magnetic field under the bias voltage of 2.7V and the excitation of 1.343eV incident photons in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0026] This embodiment takes a 47nm CrSBr tunneling device as an example:

[0027] 1) Prepare the device. Figure 1As shown, the two-dimensional layered graphite material (FLG) with a thickness of less than 10 nm and the CrSBr material with a thickness of 47 nm were obtained by mechanical exfoliation, and the graphite material (bottom FLG), the CrSBr material, and the graphite material (top FLG) were sequentially placed on the Si / SiO2 substrate with a pre-prepared electrode by electron beam exposure and electron beam evaporation by a dry transfer method, to finally prepare a tunnel junction device, wherein the overlapping position of the upper and lower graphite materials of the CrSBr material serves as a detection junction area for photoelectric performance. The optical photograph of the CrSBr tunnel junction device is as shown in Figure 2 .

[0028] 2) The tunnel junction device was cooled to 2K, a voltage of 2.7V was applied to the tunnel junction device, the incident photon energy and power were changed based on the variable wavelength supercontinuum laser, the photocurrent size and the photoresponsivity varying with the incident photon energy under the voltage were obtained, and the adjustable photocurrent was obtained.

[0029] 3) The polarization angle of the incident light was changed, as shown in Figure 3 , the photocurrent has an "8" shape distribution with the polarization angle of the incident light, the polarization of the excitation light is along the b-axis of the lattice, the photocurrent has a tunable response characteristic with the external light field, the first main absorption peak is at 1.376eV, and the photocurrent is enhanced due to the exciton absorption of the conduction band bottom and the valence band top, the second absorption peak appears at 1.745eV and above, and the photocurrent is enhanced due to the exciton absorption of the conduction band bottom and the second valence band top; that is, the polarization of the excitation light is along the b-axis of the lattice, corresponding to the maximum photocurrent; the polarization of the excitation light is along the a-axis of the lattice, corresponding to the minimum photocurrent, and the photocurrent linear dichroism spectrum is obtained by dividing the photocurrent-photon energy spectrum of the incident light polarized along the two extreme directions. The linear dichroism is derived from the ratio of the photocurrent along the a-axis and the b-axis, which can reach nearly 60 at 1.376eV energy, and can also reach nearly 20 at high energy.

[0030] 4) The polarization of the incident photon was fixed at the angle along the b-axis of the CrSBr material crystal, the applied magnetic field and the photon energy were changed, and the magnetic field-photon energy photocurrent response phase diagram was detected. As shown in Figure 4 , the photoresponsivity of the 1.376eV incident photon excitation is increased by about 6 times, and the photocurrent peak position has a significant red shift, corresponding to the highly tunable characteristic of the photocurrent with the magnetic field. Thus, under different incident photon energies, the photocurrent will have different magnetic field responses, such as slow increase (such as at 1.343eV incident photon), increase first, then decrease and increase again (such as at 1.350eV incident photon), etc. As shown in Figure 5 , taking the 1.343eV excitation photon as an example, the photocurrent change with the magnetic field is first measured, and it can be seen that the photocurrent response changes stably with the magnetic field, which can be used as a reference to detect the disturbance of the environmental magnetic field.

[0031] Finally, it is to be understood that the embodiments are presented by way of example only, and that the invention is not limited to the embodiments. It will be apparent to persons skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments described herein, but is to be accorded the full scope consistent with the claims, the drawings, and the techniques disclosed herein.

Claims

1. A method for multi-parameter photodetection based on CrSBr material tunneling structure, comprising the following steps: 1) A graphite material, a CrSBr material and a graphite material are sequentially placed on a Si / SiO2 substrate with a pre-prepared electrode by a dry transfer method to obtain a tunneling junction device; 2) The tunneling junction device is cooled to 2K, a specific voltage is applied to the tunneling junction device, the incident photon energy and power are changed based on a variable wavelength supercontinuum laser, the photocurrent size and the photoresponsivity under the voltage are obtained with the change of the incident photon energy, and a photocurrent-photon energy spectrum is obtained; 3) The polarization angle of the incident light is changed, the "8" figure distribution of the photocurrent with the incident light polarization angle in step 2) is measured, the maximum value is along the b-axis of the CrSBr material lattice, the minimum value is along the a-axis of the CrSBr material lattice, and the photocurrent linear dichroism spectrum is obtained by dividing the photocurrent-photon energy spectrum of the incident light polarized along the two minimum value directions; 4) The incident photon polarization is fixed at the angle along the b-axis of the CrSBr material crystal, the applied magnetic field and the photon energy are changed, and a magnetic field-photon energy photocurrent response phase diagram is obtained.

2. The method for multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, The thickness of the CrSBr material in step 1) is in the range of 20-100 nm, and the thickness of the graphite material is within 10 nm.

3. The method of multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, The specific voltage in step 2) is 2.7V, the incident photon energy is 1.3-1.9eV, and the incident photon power is 0-20μW.

4. The method for multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, In step 3), a polarizer and a 1 / 2 wave plate are added in the excitation light path to change the polarization angle of the incident light.

5. The method for multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, In step 3), a 1 / 4 wave plate is used to change the optical rotation characteristics of the incident light to obtain the photocurrent difference under the excitation of left-handed and right-handed photons.

6. The method for multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, In step 4), the applied magnetic field is from 0 to 3T, and the photon energy is from 1.30eV to 1.45eV.

7. The method of multi-parameter photodetection based on CrSBr material tunneling structure according to claim 6, wherein, The magnetic field is along the spin jump a-axis or b-axis of the CrSBr material, or the magnetic field is along the spin tilt c-axis of the CrSBr material.

8. The method for multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, A pA-precision ammeter is used to measure the tunneling junction device.

9. The method of multi-parameter photodetection based on CrSBr material tunneling structure according to claim 1, wherein, An electrostatic shield is arranged on the detection area of the tunneling junction device.

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