Design scheme and preparation method of electric pumping nano laser

Abstract

The invention relates to a design scheme for realizing an electric pumping nano laser at room temperature and a preparation method of the electric pumping nano laser, and belongs to the field of nano laser technology and micro-nano optics. The electric pumping nano laser comprises a nano optical resonant cavity with a high quality factor and an LED (light-emitting diode). Wherein the nanometer optical resonant cavity breaking through the optical diffraction limit is provided by a surface plasmon array and is used for screening nanometer lasing with matched energy. The preparation method comprises the following steps: (1) preparing the LED part; (2) preparing a surface plasmon array; and (3) the surface plasmon array part is tightly combined with the LED part. The technical core is as follows: (1) the excellent surface plasmon performance is the basis for ensuring that the nano laser reaches a threshold value; (2) barrier-free interaction between the nano optical cavity and the LED is ensured by parameters such as light transmission and thickness of the substrate of the surface plasmon array; and (3) the resonant wavelength of the nano optical cavity is ensured to be matched with the LED light-emitting wave band. The nanometer laser can be used as an on-chip light source to play an important role in the fields of photoelectric integration, photoelectric interconnection, quantum computing and the like.

Description

Technical Field

[0001] The present invention relates to the fields of nano laser technology and micro-nano optics, and in particular to a design scheme and a preparation method of an electrically pumped nano laser. Background Art

[0002] Since the invention of laser in 1960, laser has improved human life in many fields with its excellent performance of high brightness, good directivity, strong monochromaticity and high coherence. With the growing demand for high data rate, high interconnection density and low power consumption, small size laser has become an exciting research field and has attracted a large number of researchers to study. In particular, nanolasers can generate coherent light at the nanoscale and are expected to become a key component for applications such as on-chip light sources, optoelectronic integrated chips, ultra-high density information storage, biosensing, nanolithography, super-resolution imaging and optical interconnection systems. In order to promote the widespread application of nanolasers in multiple fields, a large number of studies are developing electrically pumped nanolasers based on diversified gain media, different cavity structures and precision device designs.

[0003] Compared with the electrically pumped nanolasers based on nanoresonators, which have not yet been realized, miniaturized lasers using microresonators and nanocavities have made significant progress. Compact microlasers based on well-known microcavities, such as Fabry-Pérot (FP), photonic crystals (PC), distributed Bragg reflectors (DBR), random cavities (RC), and whispering gallery modes (WGM), have been successfully developed. With the progress of high-precision nanofabrication, it is also possible to produce electrically pumped lasers at the nanoscale. However, compared with other small lasers, the biggest feature of nanolasers is that they require a resonator that can make light oscillate at the nanoscale, which requires that the cavity must be able to break through the optical diffraction limit, and also puts higher requirements on nano-optical cavities. Surface plasmon structure (plasmonic structure) is the main way to break through the optical diffraction limit through the surface plasmon resonance (SPR) process and then realize nano-optical cavities. However, what the surface plasmon structure can provide is a metal cavity, which has non-negligible losses compared with traditional dielectric optical cavities. Therefore, the optically pumped nanolasers that have been reported either require high-energy pulsed light as a pump source or require an ultra-low temperature working environment to achieve nanolasing, which also means that the research on electrically pumped nanodevices faces greater difficulties. In fact, some reported works claim to have introduced plasmon effects to construct nanocavities. However, these works have not yet provided conclusive evidence for the realization of nanocavities. Therefore, in addition to the urgent need to solve the problem of high-quality nano-optical cavities, the innovative design of the device structure of electrically pumped nanolasers is another core issue to be solved. Summary of the invention

[0004] In view of the deficiencies pointed out in the above background technology, the purpose of the present invention is to provide a design scheme and preparation method of an electrically pumped nanolaser, which solves the problem of having both (1) an ultra-high performance nano-optical cavity and (2) an innovative device structure.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A design scheme and preparation method of an electrically pumped nano-laser, comprising the following steps:

[0007] (1) Preparation of LED (light-emitting diode) parts;

[0008] (2) Fabrication of surface plasmon arrays, i.e., nano-optical resonant cavities;

[0009] (3) The surface plasmon array is combined with the LED part, and the surface plasmon array is closely attached to the surface of the LED part, perpendicular to the light emitting direction of the LED;

[0010] (4) The device described in (3) is electrically pumped, and the surface plasmon cavity selects narrow-band nanolasers that meet energy matching from the broadband LED light.

[0011] The LED described in step (1) can be any LED such as COB LED, QLED, PeLED, OLED, etc.

[0012] The LED described in step (1) can emit light of different wavelengths such as ultraviolet light, blue light, green light, red light or white light.

[0013] The LED composition described in step (1) can be a pn junction type formed by a p-type semiconductor, a quantum well MQW, and an n-type semiconductor, or a multilayer structure consisting of a transmission layer, a light-emitting layer, and a cathode and an anode.

[0014] The surface plasmon array described in step (2) can be prepared by direct writing lithography, nanoimprinting, ultraviolet holographic lithography, etc.

[0015] The surface plasmon array arrangement in step (2) may be an orthogonal arrangement, a regular hexagonal arrangement or other arrangements.

[0016] The shape of the nanoparticles in the surface plasmon array in step (2) can be a sphere, a cylinder, a bow tie or other polygons.

[0017] The surface plasmon array coating metal in step (2) can be gold, silver, aluminum, copper or other materials.

[0018] The coating thickness of the surface plasmon material of the surface plasmon array described in step (2) is 50-200nm.

[0019] The surface plasmon array and LED in step (3) can be prepared separately and then bonded together, or they can be prepared as a whole, layer by layer.

[0020] The resonant wavelength of the surface plasmon nano-optical cavity described in step (4) is consistent with the wavelength of the final emitted nano-laser.

[0021] The polarization direction of the nano-laser selected in step (4) is consistent with the polarization direction of the nano-optical cavity.

[0022] The present invention has the following advantages:

[0023] 1. The surface plasmon array in the present invention can support an SPR resonance mode with both extremely high quality factor (Quality factor, Q) and ultra-strong near-field enhancement, which is a prerequisite advantage for lowering the threshold of nanolasers.

[0024] 2. The surface plasmon array in the present invention can provide a nano-optical cavity in the visible light band, which is an advantage for realizing the development of electrically pumped nano-lasers in the visible light band at room temperature.

[0025] 3. The present invention fully utilizes the advantage that the surface plasmon array can be prepared on a large area, providing advantages for convenient combination with LED parts and convenient detection of nano-lasers.

[0026] 4. The present invention fully utilizes the currently mature LED preparation process, which provides important advantages for the development of the electrically pumped nano-laser in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of an electrically pumped nanolaser provided in an embodiment of the present invention.

[0028] In the figure: 1, 1'-power source; 2, 2'-surface plasmon array; 3, 3'-n-type semiconductor or electron transport layer; 4, 4'-quantum well or light-emitting layer; 5, 5'-p-type semiconductor or hole transport layer; 6, 6'-substrate.

[0029] Figure 2 It is a spectrum diagram provided by an embodiment of the present invention.

[0030] In the figure: 1-SPR reflection spectrum; 2-LED electroluminescence spectrum; 3-electrically pumped nanolaser spectrum. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] 1. A design scheme of an electrically pumped nano-laser provided by the present invention is as follows Figure 1 and Figure 2 The detailed steps are as follows:

[0033] (1) Preparation of LED (light-emitting diode) parts:

[0034] 1. Substrate selection and processing: Select the appropriate substrate material. Common substrate materials include sapphire or aluminum nitride (AlN). Ensure that the substrate is clean and flat after cleaning and surface treatment. Figure 1 As shown in 6 and 6';

[0035] 2. Deposition of n-type semiconductor layer: Deposit a layer of n-type semiconductor material on the substrate, usually gallium nitride (GaN), with a thickness of several microns. This process is usually carried out using metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) technology, such as Figure 1 5 and 5';

[0036] 3. Deposition of multi-layer quantum well structure: A multi-layer quantum well structure is deposited on the n-type semiconductor layer, in which the light-emitting active layer is generally formed by alternating deposition of gallium germanium (GaGe) and gallium nitride (GaN), and the thickness of the quantum well is usually between 10-20nm. In order to ensure the uniformity and optoelectronic performance of the quantum well, multiple fine process controls are required during the deposition process, such as Figure 1 As shown in 4 and 4';

[0037] 4. Deposition of p-type semiconductor layer: p-type semiconductor material is deposited on the quantum well structure, usually doped gallium nitride (Mg:GaN) material, with a thickness of several hundred nanometers to several microns. This layer is responsible for providing a forward carrier transmission path, such as Figure 1 As shown in 3 and 3';

[0038] 5. Surface treatment and electrode preparation: The finished chip structure is surface treated, including etching to form a specific structural profile and remove surface impurities. Subsequently, metal electrodes are made on the surface of p-type and n-type semiconductors to form positive and negative electrodes to provide electrical connections for the LED driver, such as Figure 1 As shown in 1 and 1'.

[0039] 6. Or directly choose commercial LED.

[0040] (2) Preparation of surface plasmon arrays, i.e., nano-optical resonant cavities:

[0041] 1. Substrate processing: clean the glass substrate and spin-coat positive photoresist with a coating thickness of about 0.5 microns;

[0042] 2. Preparation of photolithographic pattern: Use holographic lithography to expose the photoresist pattern, then develop it with developer, fix it with clean water and blow dry it with nitrogen;

[0043] 3. Metal deposition: Using the photoresist pattern as a template, metal deposition is performed to obtain a surface plasmon array consistent with its surface morphology;

[0044] 4. Pattern transfer: Pattern transfer is performed through UV curing agent to prepare a nano-optical resonant cavity that can be well combined with LED, such as Figure 1 As shown in Figures 2 and 2'.

[0045] (3) Combination of plasmon array and LED: The silver nanoarray is closely attached to the LED through the transfer process, and kept perpendicular to the light emitting direction of the LED, thus forming an electrically pumped nanolaser, such as Figure 1 shown.

[0047] (4) The device described in (3) is electrically pumped, and the surface plasmon cavity selects nanolasers that meet energy matching. The reflection spectrum of the surface plasmon is as follows: Figure 2 As shown in Figure 1, the electroluminescence spectrum of LED is as follows Figure 2 As shown in 2, the nano-laser signal measured by the electrically pumped nano-laser composed of the two on the above-mentioned detection device is as follows Figure 2 As shown in Figure 3, the wavelength of the electrically pumped nano-laser signal is 598 nm and the line width is 4.1381 nm.

[0048] In a specific implementation case, different LEDs can be prepared by changing the p-type semiconductor, n-type semiconductor and quantum well.

[0049] In a specific implementation case, different surface plasmon arrays can be prepared by changing the grating period and the metal material.

[0050] In a specific implementation case, the surface plasmon array can be closely fitted with the LED, or the preparation process of the LED can be first performed and then the preparation process of the plasmon nano-optical cavity can be continued in the light emitting direction.

[0051] In a specific implementation case, different electrically pumped nano-optical devices can be prepared by designing the resonant wavelength of the surface plasmon array to match the light-emitting band of the LED.

[0052] The above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A design scheme and preparation method of an electrically pumped nanolaser, comprising the following steps: (1) Preparation of LED (light-emitting diode) parts; (2) Fabrication of surface plasmon arrays, i.e., nano-optical resonant cavities; (3) The surface plasmon array is combined with the LED part, and the surface plasmon array is closely attached to the surface of the LED part, perpendicular to the light emitting direction of the LED; (4) The device described in (3) is electrically pumped, and the surface plasmon cavity selects narrow-band nanolasers that meet energy matching from the broadband LED light.

2. The preparation method according to claim 1, characterized in that In step (1), the LED seed light source can emit light of different wavelengths such as ultraviolet light, blue light, green light, red light or white light.

3. The preparation method according to claim 1, characterized in that: In step (1), the type of LED can be COB LED, QLED, PeLEDs or OLED.

4. The preparation method according to claim 1, characterized in that: In step (1), the structure of the LED may include a pn junction composed of a p-type semiconductor and an n-type semiconductor, or a multilayer structure composed of a transmission layer, a light-emitting layer, and positive and negative electrodes.

5. The preparation method according to claim 1, characterized in that: In step (2), the surface plasmon array can be prepared by direct writing lithography, nanoimprinting, or ultraviolet holographic lithography.

6. The preparation method according to claim 1, characterized in that: In step (2), the period of the surface plasmon array ranges from 300nm to 1000nm, the array arrangement can be orthogonal arrangement, regular hexagonal arrangement or other forms, the metal plating material includes gold, silver, aluminum or copper, and the plating thickness ranges from 50nm to 200nm.

7. The preparation method according to claim 1, characterized in that: In step (3), the surface plasmon array and the LED can be combined by preparing them separately and then bonding them together, or by an integral preparation process, which is completed layer by layer.

8. The preparation method according to claim 1, characterized in that: In step (4), the emission wavelength of the nanolaser is consistent with the resonance wavelength of the surface plasmon optical cavity.

9. The preparation method according to claim 1, characterized in that: In step (4), the polarization direction of the screened nanolaser is consistent with the polarization direction of the nano-optical cavity.

10. An electrically pumped nano-laser and a method for manufacturing the same according to any one of claims 1 to 9, characterized in that: The electrically pumped nanolaser integrates a surface plasmon optical cavity and an LED seed light source, wherein the LED is a light source that can emit light of different wavelengths; the surface plasmon optical cavity is composed of a metal periodic array, which can break through the optical diffraction limit, the array period is 300nm to 1000nm, and the resonance wavelength has a spectral overlap with the LED light-emitting band. When a voltage is applied to the laser, the surface plasmon cavity selects a nanolaser that meets the energy matching.

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