Plasmon-based semiconductor laser and manufacturing method thereof

Abstract

The invention discloses a semiconductor laser based on plasmons and a manufacturing method thereof. The semiconductor laser comprises a substrate; the semiconductor gain layer is formed on the surface of the substrate; the metal nano-particle array is formed on the surface of the semiconductor gain layer, the metal nano-particle array comprises a plurality of Al metal nano-particles which are arranged in an array mode, the metal nano-particle array meets the condition that g is larger than or equal to 10 nm and smaller than or equal to 30 nm, and g is the distance between any two adjacent Al metal nano-particles. According to the plasmon-based semiconductor laser and the manufacturing method thereof, the performance of the semiconductor laser can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lasers, and in particular to a semiconductor laser based on plasmons and a manufacturing method thereof. Background Art

[0002] The rise of nanotechnology and the integration of optoelectronic devices have led to the development of lasers in the direction of miniaturization and micro-miniaturization. Laser light sources have gradually become one of the research hotspots in the field of lasers due to their extremely small physical size and excellent performance in low-power devices. They also have broad application prospects in optical interconnection, biological detection, medical treatment, and data storage. However, traditional semiconductor optical devices have diffraction limits, and their optical cavity size is at least half of the half wavelength, which is difficult to meet the needs of device integration.

[0003] The emergence of the localization of the metal surface plasmon field makes it possible to break through the optical diffraction limit. The generation of metal surface plasmons is due to the collective oscillation of the conductive electron gas in the metal, forming a resonant coupling between light and plasmons, and generating a strong local field at the interface. It can be applied to high-sensitivity sensors using surface enhanced Raman scattering (SERS), flyers, LEDs, detectors and other devices. Combining surface plasmon technology with lasers can realize nanolasers that break through the optical diffraction limit, which is an effective means to achieve the miniaturization and micro-miniaturization of lasers. The incident light wave couples with the electron oscillation to form a surface plasmon and propagates and amplifies. The light wave is confined to the area near the metal surface, which can greatly compress the spatial distribution scale of the electromagnetic field, effectively reduce the size of the laser and the volume of the light mode, and at the same time, the Purcell effect can be used to increase the spontaneous emission factor, which plays a role in reducing the laser threshold. It is a nanolaser with broad development prospects.

[0004] For plasmon-enhanced lasers, the factors that affect their performance are mainly: gain medium, plasmon metal and laser structure. Three basic conditions must be met for the normal operation of semiconductor lasers: a) population inversion; b) suitable optical resonant cavity; c) threshold condition. The physical process of surface plasmon laser lasing is: the optical gain is still provided by the semiconductor gain medium. The gain medium is excited by an external source, and the electron-hole pairs in the gain medium are excited to produce excitons. During the energy level transition recombination process, the energy is transferred to the metal surface, so that the light couples with the free electrons on the metal surface to produce plasmon resonance. At the same time, the plasmon resonance further excites the transition of electrons in the gain medium. When the electrons in the excited state energy level in the gain medium meet the population inversion condition, plasmon laser radiation will be generated. For plasmon-coupled semiconductor lasers, the quality factor of the plasmon cavity is an important parameter to characterize the optical loss of the resonant cavity. It is used to evaluate the quality of the resonant cavity and is the key to evaluating laser performance. A small quality factor means large optical loss, which makes the laser have a high laser threshold. During the use of the device, a large amount of Joule heat will be generated, resulting in a short device life. At the same time, there is a problem of high energy consumption, which is not conducive to the integrated application of lasers.

[0005] Gain materials that can be used for plasmon nanolasers can be found from deep ultraviolet to infrared (NIR). II-VI semiconductor materials, such as ZnO, can provide high gain in the ultraviolet and red bands. III-V semiconductor materials, GaN materials, as a typical representative of the third generation of semiconductor materials, can work stably under high temperature conditions with their superior performance, while reducing device energy consumption has become the main direction of the future intelligent electronic information industry. As another high-end optoelectronic device, GaN-based lasers have the advantages of adjustable wavelength, concentrated energy, high efficiency, small size, and large-scale production. They have broad application prospects in laser display, laser lighting, laser processing, underwater communication, biochemical detection and other fields. Through the composition regulation of GaN and its AlInGaN quaternary alloy, the bandgap width can be adjusted from 0.7eV to 6.2eV. By adjusting the In component content in the InGaN ternary alloy, the luminescence range can cover the entire visible light band, but the defect density in the material is still very high, resulting in the low efficiency of high In component InGaN in the yellow-green light band.

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0007] The object of the present invention is to provide a plasmon-based semiconductor laser and a manufacturing method thereof, which can greatly improve the performance of the semiconductor laser.

[0008] To achieve the above-mentioned purpose, an embodiment of the present invention provides a plasmon-based semiconductor laser, comprising: a substrate; a semiconductor gain layer formed on the surface of the substrate, wherein the bandgap width of the semiconductor gain layer ranges from 2ev to 3.55ev; a metal nanoparticle array formed on the surface of the semiconductor gain layer, wherein the metal nanoparticle array comprises a plurality of Al metal nanoparticles arranged in an array, and wherein the metal nanoparticle array satisfies 10nm≦g≦30nm, wherein g is the distance between any two adjacent Al metal nanoparticles.

[0009] In one or more embodiments of the present invention, the size of each Al metal nanoparticle satisfies 140nm≦d≦200nm, 30nm≦h≦70nm, wherein d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle.

[0010] In one or more embodiments of the present invention, the semiconductor gain layer includes an InGaN / GaN quantum well structure.

[0011] In one or more embodiments of the present invention, the content of In component in the InGaN is regulated so that the bandgap width of the InGaN / GaN quantum well structure is in the range of 2ev-3.55ev.

[0012] In one or more embodiments of the present invention, the quality factor Q of the metal nanoparticle array is in the range of: 60 <Q<150.。

[0013] In one or more embodiments of the present invention, the substrate is selected from a GaN substrate.

[0014] An embodiment of the present invention also provides a method for manufacturing a plasmon-based semiconductor laser, comprising: providing a substrate; forming a semiconductor gain layer on the surface of the substrate, and regulating the bandgap width of the semiconductor gain layer to be between 2ev-3.55ev; forming a metal nanoparticle array on the surface of the semiconductor gain layer, the metal nanoparticle array comprising a plurality of Al metal nanoparticles arranged in an array, and the metal nanoparticle array satisfies 10nm≦g≦30nm, wherein g is the distance between any two adjacent Al metal nanoparticles.

[0015] In one or more embodiments of the present invention, the size of each Al metal nanoparticle satisfies 140nm≦d≦200nm, 30nm≦h≦70nm, wherein d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle.

[0016] In one or more embodiments of the present invention, the semiconductor gain layer includes an InGaN / GaN quantum well structure, and the content of In component in the InGaN is regulated so that the bandgap width of the InGaN / GaN quantum well structure ranges from 2ev to 3.55ev.

[0017] In one or more embodiments of the present invention, the substrate is selected from a GaN substrate.

[0018] Compared with the prior art, the semiconductor laser based on plasmon and the manufacturing method thereof according to the embodiment of the present invention realize the diffraction resonance mode of plasmon of the metal nanoparticle array in an asymmetric medium environment. The asymmetric medium environment refers to that one end of the metal nanoparticle array is provided with a semiconductor gain layer and the other end is exposed to the air.

[0019] According to the plasmon-based semiconductor laser and its manufacturing method of the embodiment of the present invention, by regulating the spacing and size of Al metal nanoparticles in the metal nanoparticle array and coupling with the InGaN / GaN quantum well structure with a bandgap width regulated to a specific range, the Al metal nanoparticles appear to have a high quality factor, and the laser based on the plasmon InGaN-GaN quantum well structure is realized, thereby greatly improving the performance of the laser.

[0020] The plasmon-based semiconductor laser and the manufacturing method thereof according to the embodiments of the present invention have a simple structure, a simple manufacturing method and high performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of a plasmon-based semiconductor laser according to an embodiment of the present invention.

[0022] Figure 2 It is the absorption curve of different periodic structures under Al metal nanoparticle array;

[0023] Figure 3 It is the electric field distribution diagram under the action of parallel light and laser;

[0024] Figure 4 is a process flow chart of a method for manufacturing a semiconductor laser based on plasmon according to an embodiment of the present invention;

[0025] Figure 5a and Figure 5b It is a schematic diagram of the structural steps of the manufacturing process of a plasmon-based semiconductor laser according to one embodiment of the present invention. DETAILED DESCRIPTION

[0026] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0027] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0028] As mentioned in the background technology, the emergence of the localization of the plasmon light field on the metal surface makes it possible to break through the optical diffraction limit. The plasmon array diffraction resonance mode has a high quality factor and a small mode volume, and has potential application value in plasmon resonance lasers. In existing plasmon-based lasers, it is generally believed that the periodic diffraction resonance mode formed by the metal particle array requires the refractive index matching of the upper and lower surfaces (that is, a dielectric layer must be formed at both ends of the metal particle array) in order to couple as a plasmon resonance cavity and a gain medium to prepare a new type of plasmon laser, such as Teri W. Odom et al. [Lasing action in strongly coupled plasmonic nanocavity arrays, 2013]. Secondly, in existing plasmon-based lasers, a coating layer needs to be formed outside the conventional metal nanoparticle structure or metal core-shell cavity, which is complex to prepare and has a small quality factor. A small quality factor means large optical loss, which makes the laser have a high laser threshold. A large amount of Joule heat will be generated during the use of the device, resulting in a short device life. At the same time, there is a problem of high energy consumption, which is not conducive to the integrated application of lasers.

[0029] In order to solve the above technical problems, the present invention provides a semiconductor laser based on plasmon and a method for manufacturing the same, which realizes the diffraction resonance mode of plasmons in a metal nanoparticle array in an asymmetric medium environment, and by regulating the spacing of Al metal nanoparticles in the metal nanoparticle array and limiting the size, coupled with an InGaN / GaN quantum well structure regulated to a specific range of bandgap width, a phenomenon of having a high quality factor is achieved, and the emission of laser light based on the plasmon InGaN-GaN quantum well structure is achieved, thereby greatly improving the performance of the laser.

[0030] like Figure 1As shown, a semiconductor laser based on plasmon according to an embodiment of the present invention includes: a substrate 10, a semiconductor gain layer 20 and a metal nanoparticle array 30. The substrate 10 is preferably a GaN substrate. The semiconductor gain layer 20 is formed on the surface of the substrate 10; the metal nanoparticle array 30 is formed on the surface of the semiconductor gain layer 20. The metal nanoparticle array 30 includes a plurality of Al metal nanoparticles arranged in an array, and the metal nanoparticle array satisfies 10nm≦g≦30nm, where g is the distance between any two adjacent Al metal nanoparticles. The size of each Al metal nanoparticle satisfies 140nm≦d≦200nm, 30nm≦h≦70nm, where d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle.

[0031] In one embodiment, the bandgap width of the semiconductor gain layer is preferably in the range of 2ev-3.55ev, that is, the luminescence peak of the semiconductor gain layer is between 350nm-600nm. The semiconductor gain layer includes an InGaN / GaN quantum well structure, and the number of the InGaN / GaN quantum well structures can be single or multiple. The bandgap width of the InGaN / GaN quantum well structure can be adjusted to be within the range of 2ev-3.55ev by adjusting the In component content in InGaN. In the above technical solution, the quality factor Q of the metal nanoparticle array is in the range of 60 <Q<150。

[0032] refer to Figure 2 and Figure 3 As shown, Figure 2 The absorption curves of different periodic structures of Al metal nanoparticle arrays are shown. Figure 2 It shows that on a high refractive index material, an array of Al metal nanoparticles with a small spacing but a large particle diameter exhibits a very narrow half-peak width or a high quality factor. Figure 3 This indicates that the electric field of the periodic diffraction peak is mainly distributed on the interface of the Al-quantum well, and the plasmon resonance further excites the transition of electrons in the gain medium, which is beneficial to plasmon laser radiation.

[0033] In this embodiment, on a high refractive index material body, an Al metal nanoparticle array with a small spacing but a large particle diameter exhibits a periodic diffraction pattern through coupling between particles, showing a very narrow half-width or a high quality factor. At the same time, the strong interface field further excites the transition of electrons in the gain medium, which is beneficial to plasmon laser radiation.

[0034] refer to Figure 4As shown, an embodiment of the present invention also provides a method for manufacturing the above-mentioned semiconductor laser based on plasmons, including: s1: providing a substrate; s2: forming a semiconductor gain layer on the surface of the substrate, and adjusting the bandgap width of the semiconductor gain layer to be between 2ev-3.55ev; s3: forming a metal nanoparticle array on the surface of the semiconductor gain layer. The metal nanoparticle array includes a plurality of Al metal nanoparticles arranged in an array, and the metal nanoparticle array satisfies 10nm≦g≦30nm, 140nm≦d≦200nm, 30nm≦h≦70nm, wherein p is the distance between any two adjacent Al metal nanoparticles, d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle.

[0035] The following is combined with Figure 5a and 5b The present invention is further explained in a clear and complete manner with respect to the manufacturing process structure steps of a semiconductor laser based on plasmons.

[0036] refer to Figure 5a As shown, a substrate 10 is provided, wherein the substrate 10 is preferably a GaN substrate.

[0037] refer to Figure 5b As shown, a semiconductor gain layer 20 is formed on a substrate 10, and the bandgap width of the semiconductor gain layer 20 is adjusted to be between 2ev and 3.55ev. The semiconductor gain layer includes an InGaN / GaN quantum well structure, and the bandgap width of the InGaN / GaN quantum well structure is adjusted to be within the range of 2ev-3.55ev by adjusting the In component content in InGaN.

[0038] refer to Figure 1 As shown, metal nanoparticles, preferably aluminum nanoparticles, are grown on the surface of the semiconductor gain layer 20 away from the substrate 10 by electron beam evaporation to obtain a metal nanoparticle array 30-Al metal nanoparticle array with a periodic structure.

[0039] Exemplarily, the metal nanoparticle array 30 is a periodic metal particle array. Preferably, the metal nanoparticle array 30 includes a plurality of Al metal nanoparticles arranged in an array, and the metal nanoparticle array satisfies 10nm≦g≦30nm, where p is the spacing between any two adjacent Al metal nanoparticles. The size of each Al metal nanoparticle satisfies 140nm≦d≦200nm, 30nm≦h≦70nm, where d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle. The shape of the metal particles is preferably columnar, but is not limited thereto.

[0040] Compared with the prior art, the semiconductor laser based on plasmon and the manufacturing method thereof according to the embodiment of the present invention realizes the diffraction resonance mode of plasmon of the metal nanoparticle array in an asymmetric medium environment by regulating the spacing of Al metal nanoparticles in the metal nanoparticle array. The asymmetric medium environment refers to a semiconductor gain layer disposed at one end of the metal nanoparticle array and exposed to air at the other end.

[0041] According to the plasmon-based semiconductor laser and its manufacturing method of the embodiment of the present invention, by regulating the spacing and size of Al metal nanoparticles in the metal nanoparticle array, combined with a semiconductor gain layer in a specific bandgap width range, the metal nanoparticle array appears to have a high quality factor, and the laser emission based on the plasmon InGaN-GaN quantum well structure is achieved, thereby greatly improving the performance of the laser.

[0042] The plasmon-based semiconductor laser and the manufacturing method thereof according to the embodiments of the present invention have a simple structure, a simple manufacturing method and high performance.

[0043] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A semiconductor laser based on plasmon, characterized in that: include: substrate; A semiconductor gain layer is formed on the surface of the substrate, and the bandgap width of the semiconductor gain layer ranges from 2 eV to 3.55 eV; A metal nanoparticle array is formed on the surface of the semiconductor gain layer. The metal nanoparticle array includes a plurality of Al metal nanoparticles arranged in an array. The metal nanoparticle array satisfies 10nm≦g≦30nm, wherein g is the distance between any two adjacent Al metal nanoparticles.

2. The semiconductor laser based on plasmon according to claim 1, characterized in that: The size of each Al metal nanoparticle satisfies 140 nm≦d≦200 nm, 30 nm≦h≦70 nm, wherein d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle.

3. The semiconductor laser based on plasmon according to claim 1, characterized in that: The semiconductor gain layer includes an InGaN / GaN quantum well structure.

4. The semiconductor laser based on plasmon according to claim 3, characterized in that: The content of In component in the InGaN is regulated so that the bandgap width of the InGaN / GaN quantum well structure is in the range of 2ev-3.55ev.

5. The semiconductor laser based on plasmon according to claim 1, characterized in that: The quality factor Q of the metal nanoparticle array is in the range of: 60 <Q<150。 6. The semiconductor laser based on plasmon according to claim 1, characterized in that: The substrate is selected from GaN substrate.

7. The method for manufacturing a semiconductor laser based on plasmon according to any one of claims 1 to 6, characterized in that: include: providing a substrate; Forming a semiconductor gain layer on the surface of the substrate, and adjusting the bandgap width of the semiconductor gain layer to be between 2 eV and 3.55 eV; A metal nanoparticle array is formed on the surface of the semiconductor gain layer. The metal nanoparticle array includes a plurality of Al metal nanoparticles arranged in an array. The metal nanoparticle array satisfies 10nm≦g≦30nm, wherein g is the distance between any two adjacent Al metal nanoparticles.

8. The method for manufacturing a semiconductor laser based on plasmon according to claim 7, characterized in that: The size of each Al metal nanoparticle satisfies 140 nm≦d≦200 nm, 30 nm≦h≦70 nm, wherein d is the diameter of each Al metal nanoparticle, and h is the thickness of each Al metal nanoparticle.

9. The method for manufacturing a semiconductor laser based on plasmon according to claim 7, characterized in that: The semiconductor gain layer includes an InGaN / GaN quantum well structure, and the content of In component in the InGaN is regulated so that the bandgap width of the InGaN / GaN quantum well structure ranges from 2ev to 3.55ev.

10. The method for manufacturing a semiconductor laser based on plasmon according to claim 7, characterized in that: The substrate is selected from GaN substrate.

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