Near-infrared plasmon laser device with adjustable laser wavelength and preparation method thereof

Abstract

The invention belongs to the field of photoelectric laser materials, and particularly relates to a laser wavelength adjustable near-infrared plasmon laser device and a preparation method thereof.The laser wavelength adjustable near-infrared plasmon laser device comprises a substrate, a metal layer, an insulating layer and an InSexTe (1-x) two-dimensional material layer which are sequentially constructed from bottom to top; wherein an annular groove is etched on the upper surface of the metal layer. According to the invention, the annular groove with the plano-concave structure is innovatively arranged in the metal layer in a sunken manner, and further combined with the InSexTe1-x two-dimensional material layer, so that the combined control of the structure and the material can be realized, the laser emission effect of the material can be remarkably improved, the material is enabled to meet the near-infrared laser emission requirement, the excitation effect of the material under near infrared is improved, and the near-infrared laser emission efficiency is improved. And meanwhile, the laser emission wavelength of the device is adjustable by using a component-adjustable two-dimensional material. The invention designs a device structure which does not depend on material morphology, and a method which is simple in preparation and has universality.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of micro-nano laser devices, and particularly relates to a near-infrared plasmonic laser device. Background Art

[0002] Since the first laser was invented by Maiman in 1960, the progress of laser technology has greatly promoted the research and development of modern science and technology of mankind. With the development of integrated circuits along Moore's law, the size of electronic components has been continuously reduced. In order to match the size of laser devices with that of electronic components, the miniaturization of laser device size has become inevitable. At present, certain progress has been made in micro-nano laser devices based on two-dimensional materials. However, these laser devices based on optical modes are restricted by the optical diffraction limit, and the physical size and mode volume of the laser cannot be further reduced. 1-5 Plasmonics is an effective method to break through the optical diffraction limit at present. The size and mode volume of a surface plasmonic mode laser device constructed by coupling a semiconductor gain medium with a metal can be smaller than the optical diffraction limit. 6-8 In theory, the device size of a laser device operating based on the plasmonic mode can be reduced to dozens or even more than a dozen nanometers, showing prominent application prospects in the field of small-size lasers.

[0003] Although the device size can be reduced to the nanometer level by constructing a plasmonic laser at present, most plasmonic lasers use a gain semiconductor as the optical cavity and are overly dependent on the semiconductor morphology. 9-11 This restricts the material preparation means and device preparation methods. At the same time, the operating wavelengths of current plasmonic lasers are distributed in the ultraviolet and visible spectral ranges. For near-infrared plasmonic lasers, due to the strong absorption and significant ohmic losses of common metals such as gold and silver in the near-infrared band, it is difficult to achieve due to the increased thermal loss. Therefore, it is necessary to design a near-infrared plasmonic laser device that has no dependence on the material morphology, is simple to prepare, and has universality.

[0004] References

[0005] 1. Wu, S. et al. Monolayer semiconductor nanocavity lasers with ultralow thresholds. Nature 520, 69 - 72, (2015).

[0006] 2. Liu, Y. et al. Room temperature nanocavity laser with interlayer excitons in 2D heterostructures. Science Advances 5, eaa v4506, (2019).

[0007] 3. Ye, Y., et al. Monolayer excitonic laser. Nature Photonics 9, 733 - 737, (2015).

[0008] 4. Sung, J., et al. Room - temperature continuous - wave indirect - bandgap transition lasing in an ultra - thin WS2 disk. Nature Photonics 16, 792 - 797, (2022).

[0009] 5. Li, Y., et al. Room - temperature continuous - wave lasing from monolayer molybdenum ditelluride integrated with a silicon nanobeam cavity. Nature Nanotechnology 12, 987 - 992, (2017).

[0010] 6. Noginov, M. A., et al. Demonstration of a spaser - based nanolaser. Nature 460, 1110 - 1112, (2009).

[0011] 7. Oulton, R. F., et al. Plasmon lasers at deep subwavelength scale. Nature 461, 629 - 632, (2009).

[0012] 8. Ma, R. M., et al. Room - temperature sub - diffraction - limited plasmon laser by total internal reflection. Nature Materials 10, 110 - 113, (2011).

[0013] 9. Wu, Z., et al. All - Inorganic CsPbBr3 Nanowire Based Plasmonic Lasers. Advanced Optical Materials 6, (2018).

[0014] 10. Wang, S. et al. Unusual scaling laws for plasmonic nanolasers beyond the diffraction limit. Nature Communications 8, 1889, (2017).

[0015] 11. Li, C. et al. Surface-Plasmon-Assisted Metal Halide Perovskite Small Lasers. Advanced Optical Materials 7, (2019). Summary of the Invention

[0016] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a near-infrared plasmonic laser device with tunable laser wavelength, aiming to provide a near-infrared plasmonic laser device with a simple structure, excellent performance, and breaking through the optical diffraction limit.

[0017] The second purpose of the present invention is to provide the preparation and application of the above-mentioned near-infrared plasmonic laser device with tunable laser wavelength.

[0018] For two-dimensional material plasmonic laser devices, it is difficult to achieve near-infrared lasers, and the laser wavelength is difficult to tune. Moreover, the structure of near-infrared plasmonic lasers is relatively complex, and their excitation thresholds are relatively higher compared to visible light. In view of this problem, through in-depth research, the present invention provides the following solutions:

[0019] A near-infrared plasmonic laser device with tunable laser wavelength, comprising a substrate, a metal layer, an insulating layer, and an InSe x Te 1-x two-dimensional material layer, sequentially constructed from bottom to top;

[0020] Wherein, an annular groove (also referred to as a feedback cavity in the present invention) is etched on the upper surface of the metal layer;

[0021] InSe x Te 1-x In the two-dimensional material of InSe

[0022] The present invention innovatively sets an annular groove with a plano-concave structure in the metal layer, and further cooperates with the x Te 1-x two-dimensional material layer of InSe

[0023] In the present invention, the annular groove has a smooth side wall.

[0024] Preferably, the included angle between the side wall and the plane of the metal layer is 90 ± 5°.

[0025] Preferably, the planar shape of the annular groove is circular, square, regular polygon or equilateral triangle.

[0026] In the present invention, the groove width of the annular groove is 0.8 μm to 2 μm; the groove depth is 0.8 to 1 times the height of the gold layer.

[0027] In the present invention, the substrate is a SiO2 / Si substrate, where the thickness of Si is 0.5 to 1 mm and the thickness of SiO2 is 150 to 400 nm.

[0028] In the present invention, the metal layer can be an Au layer (gold layer). In addition, the thickness of the metal layer is 100 to 250 nm.

[0029] In the present invention, the insulating layer is one or more of Al2O3, HfO2 and hBN, and its thickness is 5 to 20 nm.

[0030] In the present invention, the insulating layer covers the surface of the metal layer.

[0031] In the present invention, the InSe x Te 1-x The thickness of the two-dimensional material layer is 80 to 150 nm.

[0032] Preferably, the x InSe 1-x Te

[0033] The vertical projection of the two-dimensional material layer is within the plane of the insulating layer.

[0034] Step (1): Prepare a metal layer on the substrate;

[0035] Step (2): Perform focused ion beam etching on the metal layer in step (1) to form the annular groove in the metal layer;

[0036] Step (3): Cover the insulating layer material above the metal layer in step (2);

[0037] Step (4): Transfer InSe x Te 1-x two-dimensional material above the insulating layer material obtained in step (3), and finally perform annealing treatment.

[0038] In the present invention, in step (1), the method for preparing the metal layer may be solution growth, evaporation coating or sputtering.

[0039] In the present invention, in step (2), the acceleration voltage of the focused ion beam etching is 25 - 35 kV, and the current is 70 - 90 pA.

[0040] In the present invention, in step (3), the coverage of the insulating layer can be achieved by CVD, ALD or dry transfer technology.

[0041] In the present invention, in step (4), the temperature in the annealing stage is 100 - 180 °C, and the annealing stage is carried out under vacuum; the annealing time is 1 - 10 h.

[0042] The present invention also provides an application of the above-mentioned near-infrared plasmonic laser device with adjustable laser wavelength, which is used to prepare a plasmonic laser in the near-infrared band.

[0043] Principle and Advantage

[0044] In the prior art solution, regular-shaped two-dimensional materials such as nanowires or nanosheets prepared by chemical vapor deposition are selected as the optical gain material and the optical cavity, while the metal layer only serves as the carrier for plasmon generation. The hybrid mode oscillates and enhances within the two-dimensional material to form a laser. This solution requires the two-dimensional material to have a symmetric regular shape, narrowing the scope of application of the solution. The present invention provides a general method independent of the shape of the two-dimensional material for preparing a metal-insulating layer-InSe x Te 1-x two-dimensional material structure plasmonic laser. The method of the present invention innovatively sets an indented annular groove in the metal layer, further cooperating with InSe x Te 1-x two-dimensional material combination, enabling the plasmon generated on the metal surface to obtain effective mode feedback and finally generating a laser. The technical solution of the present invention separates the optical gain material from the mode feedback structure. The mode feedback is realized by the annular groove, and InSe x Te 1-x two-dimensional material provides optical gain, and can construct a plasmonic laser device based on any-shaped InSe x Te 1-x two-dimensional material, which is simple and universal. In addition, the invention solution has high flexibility and can design annular grooves with different shapes according to specific requirements to prepare plasmonic laser devices. Brief Description of the Drawings

[0045] Figure 1 It is a top view structure diagram of the near-infrared plasmonic laser device with adjustable laser wavelength of the present invention.

[0046] Figure 2Schematic diagram of the first step in the preparation method of a near-infrared plasmonic laser device with tunable laser wavelength according to the present invention.

[0047] Figure 3 Schematic diagram of the second step in the preparation method of a near-infrared plasmonic laser device with tunable laser wavelength according to the present invention.

[0048] Figure 4 Schematic diagram of the third step in the preparation method of a near-infrared plasmonic laser device with tunable laser wavelength according to the present invention.

[0049] Figure 5 Schematic diagram of the fourth step in the preparation method of a near-infrared plasmonic laser device with tunable laser wavelength according to the present invention.

[0050] Figure 6 Simulation diagram of the electric field distribution and mode distribution of a near-infrared plasmonic laser device with tunable laser wavelength according to the present invention.

[0051] Figure 7 Raman spectrum and laser emission spectrum diagram of a near-infrared plasmonic laser device with tunable laser wavelength according to the present invention.

[0052] Among them, 100 - substrate; 101 - metal layer; 102 - insulating layer; 103 - InSe x Te 1-x Two-dimensional material layer; 104 - annular groove. Detailed implementation manners

[0053] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners, so that those skilled in the art can understand the present invention more clearly. It should be understood that the specific implementation manners described herein are only used to explain the present invention and are not used to limit the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0054] Example 1

[0055] A near-infrared plasmonic laser device with tunable laser wavelength, see Figure 1 , including a substrate 100, a metal layer 101 with the annular groove 104, an insulating layer 102, and a two-dimensional material 103, wherein the transverse dimension of the insulating layer 102 is larger than the transverse dimensions of the annular groove 104 and InSe x Te 1-x two-dimensional material layer 103.

[0056] The basic process of this embodiment is to prepare a metal layer 101 on a prior substrate 100, then prepare an annular groove 104 by focused ion beam etching of the metal layer 101, and finally cover the annular groove 104 with an insulating layer 102 and a two-dimensional material 103 in sequence. See Figures 2 - 5 。

[0057] The substrate 100 of this embodiment is a SiO2 / Si substrate, where the thickness of Si is 525 mm and the thickness of SiO2 is 360 nm.

[0058] The metal layer (specifically the Au layer in this case) 101 of this embodiment is prepared by electron beam evaporation. The gold deposition rate is 0.2 nm / s, and the thickness of the gold thin film on the obtained substrate is 200 nm.

[0059] The annular groove 104 of this example is prepared by focused ion beam etching. The specific preparation method is as follows:

[0060] (1) Draw the shape of the annular groove 104 in a drawing software and save the file as a vector image (specifically a square annular groove 104 in this case);

[0061] (2) Place the wafer with the metal layer 101 in the focused ion beam working chamber, import the vector image file of the annular groove 104 morphology drawn in the previous step, and start etching after setting the etching parameters (30 kV voltage, 80 pA current, etching depth 200 nm);

[0062] (3) Ultrasonically clean the annular groove 104 obtained in the previous step to remove surface particle impurities.

[0063] The interface of the annular groove 104 prepared by this scheme is flat and free of impurity particles, and the boundary is clear.

[0064] By means of substrate transfer, the insulating layer 102 material Al2O3 is transferred and covered above the annular groove 104, and the planar size of Al2O3 is larger than that of the annular groove 104.

[0065] Cover the InSe x Te 1-x two-dimensional material layer 103 above the insulating layer 102. The specific process is as follows:

[0066] Prepare a series of InSe x Te 1-x materials (x is 0.8 or 0.9) on PDMS by mechanical exfoliation method. Observe the color (optical contrast) and size of the materials through an optical microscope, and select an InSe x Te 1-x with appropriate thickness, and InSe x Te 1-xThe planar dimension should be larger than the annular groove 104 and smaller than the insulating layer 102; InSe is transferred onto the Al2O3 to cover the annular groove 104 through a dry fixed-point transfer system. x Te 1-x Transfer to cover the annular groove 104 above the Al2O3.

[0067] Place the plasmonic laser device prepared by the above method in a tube furnace for vacuum high-temperature annealing treatment to increase the interfacial coupling strength between the annular groove 104 and the insulating layer 102, and between the insulating layer 102 and the two-dimensional material layer 103. The parameters of the vacuum high-temperature annealing are as follows: the vacuum degree is 10 -7 mbar, the temperature is 130 °C, and the annealing time is 4 hours. After the high-temperature annealing is completed, let the device cool naturally to room temperature. The plasmonic laser device prepared by this method has a small distance between interfaces, a high interlayer coupling strength, and a flat interface without impurity particles.

[0068] Figure 6 This is the simulation diagram of the electric field distribution and mode distribution of the plasmonic laser device in the present invention. The simulation results show that there is an obvious plasmon phenomenon on the surface of the metal layer 101.

[0069] Figure 7 This is the Raman spectrum and laser emission spectrum diagram of the plasmonic laser device in the present invention. The Raman spectrum peak positions of the two-dimensional material layer 103 with different Se / Te content ratios are different, and its fluorescence spectrum peak positions are also different. As the Te content increases, the fluorescence spectrum of the device gradually redshifts. By changing the Te component, the laser wavelength of the device can be adjusted. In addition, the narrow peak laser spectrum presented in the emission spectrum is a typical laser emission behavior.

[0070] The near-infrared plasmonic laser device with adjustable laser wavelength and its preparation method in the present invention utilize the annular groove 104 to directly regulate the plasmon mode, solving the problem of relying on the morphology of the two-dimensional material layer 103 in the preparation process of existing plasmonic laser devices. The two-dimensional material layer 103 with any morphology can be combined with the annular groove 104 and the insulating layer 102 to prepare a plasmonic laser device. The method of the present invention is simple and universal, and the device structure design has strong flexibility. The annular groove 104 can be designed into different shapes according to specific requirements, which better meets the needs of practical applications.

[0071] The above only represents the preferred embodiments of the present invention. It does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, is equally included in the patent protection scope of the present invention.

Claims

1. A near-infrared plasmonic laser device with adjustable laser wavelength, characterized in that, Including a substrate, a metal layer, an insulating layer, and InSe constructed sequentially from bottom to top x Te 1-x A two-dimensional material layer; Wherein, an annular groove is etched on the upper surface of the metal layer; InSe x Te 1-x In two-dimensional materials, x ranges from 0.8 to 0.

9.

2. The near-infrared plasmonic laser device with tunable laser wavelength according to claim 1, wherein, The annular groove has a smooth side wall; Preferably, the included angle between the side wall and the plane of the gold layer is 90±5°; Preferably, the planar shape of the annular groove is circular, square, regular polygon or equilateral triangle.

3. The near-infrared plasmonic laser device with tunable laser wavelength according to claim 1 or 2, characterized in that, The groove width of the annular groove is 0.8μm - 2μm; the groove depth is 0.8 - 1 times the height of the gold layer.

4. The near-infrared plasmonic laser device with tunable laser wavelength according to claim 1, characterized in that, The substrate is a SiO2 / Si substrate, wherein the thickness of Si is 0.5 - 1mm, and the thickness of SiO2 is 150 - 400nm.

5. The near-infrared plasmonic laser device with tunable laser wavelength according to claim 1, wherein The thickness of the metal layer is 100 - 250nm.

6. The near-infrared plasmonic laser device with tunable laser wavelength according to claim 1, characterized in that, The insulating layer is one or more of Al2O3, HfO2 and hBN, and its thickness is 5 - 20nm.

7. The near-infrared plasmonic laser device with tunable laser wavelength according to claim 1, characterized in that, The described InSe x Te 1-x The thickness of the two-dimensional material layer is 80 to 150 nm; Preferably, the InSe x Te 1-x The vertical projection of the two-dimensional material layer is within the plane of the insulating layer.

8. A method for preparing a near-infrared plasmonic laser device with tunable laser wavelength according to any one of claims 1 to 7, characterized in that the steps Comprising: Step (1): Prepare a metal layer on the substrate; Step (2): Perform focused ion beam etching on the metal layer in step (1) to form the annular groove in the metal layer; Step (3): Cover an insulating layer material above the metal layer in step (2); Step (4): Transfer InSe x Te 1-x two-dimensional material on top of the insulating layer material obtained in step (3), and finally perform annealing treatment.

9. The preparation method of the near-infrared plasmonic laser device with tunable laser wavelength according to claim 8, characterized in that In step (1), the method for preparing the metal layer is solution growth, evaporation or sputtering; Preferably, in step (2), the acceleration voltage of the focused ion beam etching is 25 - 35kV, and the current is 70 - 90pA; Preferably, in step (3), the insulating layer is formed by CVD, ALD or dry transfer technology; Preferably, in step (4), the temperature in the annealing stage is 100 - 180°C, and the annealing stage is carried out under vacuum; the annealing time is 1 - 10h.

10. Use of a near-infrared plasmonic laser device with adjustable laser wavelength according to any one of claims 1 to 7, characterized in that, It is used for preparing a plasmonic laser in the near-infrared band.

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