CN104538837A - Nanometer plasma array laser device and manufacturing method thereof - Google Patents

Abstract

The invention provides a nanometer plasma array laser device and a manufacturing method of the laser device and belongs to the technical field of optics. According to the method, photons excited by an electrical pump semiconductor nanowire p-n junction array are utilized for interacting with surface metal-dielectric films to generate surface plasmon polaritons (SPP), and then photon beams generated in a nanowire resonant cavity are restrained and regulated. According to the method, the double advantages of semiconductor nanometer structure geometric limitation and limitation and constraint of a surface plasma mode field to beams are combined, a semiconductor nanowire is utilized for integrating a working substance and the resonant cavity and achieving mode field constraint on surface plasmas, and finally the nanometer plasma laser device is formed.

Description

A nanoplasma array laser and its manufacturing method

technical field

The invention belongs to the field of optical technology, and in particular relates to a nano-plasma array laser and a manufacturing method thereof.

Background technique

Since the first laser was produced 50 years ago, some new nanotechnology has improved the micro-laser to a new field, which has set off a research boom of nano-laser. At present, the widely used nanolasers mainly include optically pumped nanoplasmonic lasers and electrically pumped semiconductor nanowire array lasers.

Optically pumped nanoplasmonic laser consists of a single semiconductor cadmium sulfide (CdS) nanowire placed horizontally on a metal-dielectric composite film to form a nanoplasmonic laser, and laser emission is achieved through pulsed laser pumping; The nano-scale slit realizes the surface plasmon local field enhancement effect for plasmon-optical hybrid pumping, and realizes laser emission at the end of the nanowire. The excitation light mode is restricted by the surface plasmon and has broken through the diffraction limit. However, it has the following disadvantages: 1) the nanowire is single, which limits the power of the laser; 2) the pumping method is pulsed laser pumping, which will greatly increase the size of the laser in practical applications; 3) the working temperature is less than 10K Ultra-low temperature is not conducive to practical application.

The manufacturing process of the electrically pumped semiconductor nanowire array laser is: prepare an n-type zinc oxide (ZnO) film on the substrate, and grow a p-type ZnO nanowire (hexagonal prism) array doped with antimony (Sb) on the n-type ZnO film At room temperature, electrodes are made on the substrate and the top of the nanowires for electrical pumping, and the laser is emitted from the top of the nanowires; its disadvantages are also very obvious: 1) The growth of nanowire arrays is irregular, which is not conducive to the synthesis of beams and power ; 2) Beam synthesis is not performed, laser packaging is not completed, and devices are not formed.

Research on nano-lasers based on zinc oxide, cadmium sulfide and other materials has attracted widespread attention from scientists. By introducing semiconductor nanowires or nano-arrays, micro-lasers and nano-lasers have reached the level of the diffraction limit, but due to the existence of the diffraction limit, semiconductor nano-lasers have been limited. The minimum size of the laser. In order to break through the limitation of the diffraction limit, the research based on surface plasmon technology, which has emerged in recent years, has made great progress in overcoming this limitation, and has gradually become a research hotspot.

Nanoplasmonic lasers combine the geometric limitations of semiconductor nanolasers and the dual advantages of surface plasmon mode field limitation in plasma lasers to break through the diffraction limit. Semiconductor nanowires are used to realize the integration of working materials and resonant cavities, and surface plasmons can break through optical diffraction. Therefore, nanoplasma lasers have the advantages of small size, good monochromaticity, good directionality, high work efficiency, low energy threshold and short response time, and will be widely used in military fields such as micro-aircraft attitude control, laser gyro, and laser guidance. Tracking, laser fuze, laser communication and laser ranging, etc., and civilian life fields such as laser dot matrix light sources in ultra-thin displays.

Contents of the invention

The object of the invention is to provide a regular array, high power, low threshold, electrically pumped nanometer plasma laser at room temperature.

The present invention utilizes the surface plasmon polaritons (SPP) excited by the photons emitted by the electric pump and the surface metal dielectric film to constrain and regulate the photon beams generated in the semiconductor nanowires, and specifically adopts the following technical scheme:

The present invention provides a kind of nano-plasma array laser, its structure is as shown in Figure 1, and Figure 2 is a schematic diagram of its structural disassembly, including ITO (Indium Tin Oxide) electrode 1, an insulating medium layer 3 provided with a through-hole array, a semiconductor The substrate 4 and the metal electrode 5, the insulating medium layer 3 is arranged on the upper surface of the semiconductor substrate 4, a semiconductor material nanowire 203 is grown on each of the through holes, and the bottom end of the semiconductor nanowire 203 is connected to the semiconductor substrate 4 directly connected; the side of the semiconductor material nanowire 203 is covered with an insulating dielectric film 202 and a metal film 201 from the inside to the outside in sequence, and its cross section is shown in Figure 3, thereby forming a nanowire array 2; the nanowire array 2 The top is directly connected to the bottom surface of the ITO electrode 1; the upper surface of the ITO electrode 1 is provided with a microlens array 7 for converging and collimating the laser light emitted from the top of each nanowire in the nanowire array; the top of the nanowire array 2 is covered by a microlens The array 7 is completely covered; the metal electrode 5 is arranged on the semiconductor substrate 4 and does not contact the insulating medium layer 3; during use, the metal electrode 5 and the ITO electrode 1 are respectively connected to the two ends of the power supply 6, and when the current reaches the threshold value, The laser can be emitted.

The length of the semiconductor material nanowire 203 is 1-20 μm.

The thickness of the insulating dielectric film 202 is 5-30 nm.

The thickness of the metal thin film 201 is 10-70nm.

Further, the through holes opened in the insulating dielectric layer 3 are circular and arranged in a hexagonal close-packed array, as shown in FIG. 4 , and the diameter of the through holes is 100-300 nm.

The present invention also provides a method for manufacturing the nanoplasma array laser, which specifically includes the following steps:

Step 1. Processing and preparation of the substrate:

A layer of insulating dielectric layer 3 is sputtered on the semiconductor substrate 4, and the insulating dielectric layer 3 is etched into a hole array structure by using electron beam etching technology (EBL). medium layer 3;

Step 2. Growth and preparation of semiconductor material nanowires:

growing semiconductor material nanowires 203 on the holes in the insulating dielectric layer 3 by chemical vapor deposition (CVD);

Step 3. Sputter Coating:

Using the magnetron sputtering process, a layer of insulating dielectric film layer 202 and metal film 201 are sequentially sputtered on the side of each semiconductor material nanowire 203 from the inside to the outside; Feedback and regulation of the field, the function of the insulating dielectric thin film layer 202 is to prevent the contact between the metal thin film 201 and the semiconductor substrate 4, resulting in an electrode short circuit between the top of the nanowire and the substrate;

Step 4. Electrode process:

Using the magnetron sputtering process, a layer of ITO electrode 1 is sputtered on the top of the nanowire array 2 composed of semiconductor material nanowires 203, and a metal electrode 5, such as silver (Ag) or gold, is vapor-deposited on the substrate 4. (Au) electrode, the metal electrode 5 is not in contact with the insulating medium layer 3;

Step 5. Microlens array beam combining:

A piece of ITO glass is covered on the top of the ITO electrode, and the conductive surface of the ITO glass is in contact with the ITO electrode sputtered in step 4; on the non-conductive surface of the ITO glass, adopt photolithography process to etch into microlens array 7, use The microlens array combines the laser light emitted by each individual nanowire into a single laser beam.

The beneficial effects of the present invention are:

The present invention combines the dual advantages of semiconductor nano lasers and plasma optical pumping lasers, realizes the combination of electrical pumping and surface plasmon confinement and field enhancement effects, and on the basis of the two, carries out The beam synthesis was achieved, and the laser emission of the electrically pumped semiconductor nanoplasma laser was finally realized, and the laser power was greatly improved.

Description of drawings

Fig. 1 is the structural representation of the nanoplasma laser provided by the present invention;

Fig. 2 is the structural disassembly schematic diagram of the nanoplasmonic laser provided by the present invention;

3 is a schematic diagram of a cross-section of a nanowire;

Figure 4 is a schematic diagram of the arrangement of a hexagonal close-packed array;

Figure 5 is a schematic diagram of the position of the hexagonal close-packed array light source of the nanoplasma laser provided by the embodiment;

Fig. 6 is the array light intensity distribution of the nanoplasmonic laser provided by the embodiment;

Fig. 7 is a grayscale image of the array photosynthesis of the nanoplasmonic laser provided in the embodiment.

Detailed ways

The present invention will be further described below in conjunction with embodiment.

Example

This embodiment provides a nanoplasma array laser, the structure of which is shown in Figure 1, and Figure 2 is a schematic diagram of its structural disassembly, the nanowire array is composed of 19 coherent light sources, as shown in Figure 5, each coherent light source is completely Same, the working mode is TEM ₀₀ mode, some specific materials, parameters and dimensions are as follows:

The semiconductor substrate 4 is a gallium nitride (GaN) substrate;

Described insulating dielectric layer 3 is SiO ₂ film layer, and its thickness is 300nm;

The _SiO2 thin film layer 3 is provided with a circular through-hole array arranged in a hexagonal close-packed array, as shown in Figure 4, the diameter of the through-hole is 200nm, and the center-to-center distance between adjacent through-holes is 1 μm; the position of each through-hole All grow ZnO nanowires 203, the length of which is 3 μm;

The side of the ZnO nanowire is covered with a layer of _SiO2 film 202 with a thickness of 10nm and an Ag film 201 with a thickness of 30nm from the inside to the outside;

In the microlens array 7 provided on the upper surface of the ITO electrode 1, the diameter and radius of curvature of each microlens are the same, and are 100 μm and 50 μm respectively;

The upper surface of the gallium nitride substrate 4 is provided with an Au electrode 5 that is not in contact with the _SiO2 thin film layer 3. When in use, the metal electrode 5 and the ITO electrode 1 are respectively connected to the two ends of the voltage and current source 6, and an appropriate current is applied. Can emit laser light.

This embodiment uses matlab to establish a corresponding program to simulate the effect of coherent combination. The coherent combination effect at a distance of 5m from the laser light source is simulated. The light intensity distribution of the array light and the grayscale image of the array light synthesis are shown in Figures 6 and 7 respectively, and The combined efficiency, that is, the ratio of the energy in the area corresponding to the z-plane and the position of the light source to the total power of the system, is 54.9%.

The fabrication method of the nanoplasma array laser provided in this embodiment is specifically as follows:

Step 1. Processing and preparation of the substrate:

A layer of SiO ₂ film layer 3 is sputtered on a p-type gallium nitride (GaN) substrate 4, and the SiO ₂ film layer is etched into a hole array structure using electron beam etching technology (EBL), and the etching depth is SiO ₂ The thickness of the film layer is so as to achieve just etching through the _SiO2 film layer;

Step 2. Growth and preparation of ZnO nanowires:

Using chemical vapor deposition (CVD), grow n-type ZnO nanowires 203 on the holes in the _SiO2 film layer 3;

Generally, ZnO nanowires 203 are grown in a 700°C environment using zinc (Zn) sheets as the Zn source, and the growth time is 30 minutes, and the temperature is naturally cooled after the growth is completed;

Step 3. Sputter Coating:

Using the magnetron sputtering process, a layer of _SiO2 thin film 202 and Ag thin film 201 are sequentially sputtered on the side of each ZnO nanowire 203 from the inside to the outside; Feedback and regulation, the function of the SiO ₂ thin film layer is to prevent the contact between the Ag thin film and the substrate and cause the electrode short circuit between the top of the nanowire and the substrate;

Step 4. Electrode process:

Using the magnetron sputtering process, a layer of ITO electrode 1 is sputtered on the top of the nanowire array 2, and a metal electrode 5, such as a silver (Ag) or gold (Au) electrode, is evaporated on the gallium nitride substrate 4. 5 is not in contact with the SiO ₂ layer 3;

Step 5. Microlens array beam combining:

Above the ITO electrode, cover a piece of ITO glass, the conductive surface of the ITO glass is in contact with the ITO electrode sputtered in step 4, and draws an electrode in the middle of the contact interlayer between the ITO electrode and the ITO glass conductive surface to facilitate connection to the power supply; The non-conductive surface of the ITO glass is etched into a microlens array 7 by a photolithography process, and the laser light emitted by each single nanowire is synthesized into a laser beam by using the microlens array.

Claims (5)

1. a nano-plasma array laser, comprising ITO electrodes (1), an insulating dielectric layer (3), a semiconductor substrate (4) and a metal electrode (5) with a through-hole array, the insulating dielectric layer (3) ) is arranged on the upper surface of the semiconductor substrate (4), and is characterized in that, a semiconductor material nanowire (203) is grown on each of the through holes, thereby forming a nanowire array (2), and the semiconductor nanowire ( 203) the bottom end is directly connected with the semiconductor substrate (4), the metal electrode (5) is arranged on the semiconductor substrate (4) and does not contact with the insulating medium layer (3), and the side of the nanowire (203) of the semiconductor material is formed by Insulation medium film layer (202) and metal film (201) are covered sequentially from inside to outside; The top of the nanowire array (2) is directly connected with the bottom surface of the ITO electrode (1); The upper surface of the ITO electrode (1) is provided with The microlens array (7) is used for converging and collimating the laser light emitted from the top of each nanowire in the nanowire array. 2. The nanoplasma array laser according to claim 1, wherein the through-hole array provided in the insulating medium layer (3) is circular and arranged in a hexagonal close-packed array, and the through-hole diameter is 100- 300nm. 3. nanoplasma array laser according to claim 2, is characterized in that, described semiconductor material nanowire (203) is ZnO nanowire, and its length is 1-20 μ m, and described insulating medium film layer (202) is The _SiO2 film layer has a thickness of 5-30nm, and the metal film (201) is an Ag film with a thickness of 10-70nm. 4. The nanoplasma array laser according to claim 1, characterized in that, the metal electrode (5) is a gold (Au) electrode or a silver (Ag) electrode. 5. The manufacture method of nanoplasmonic array laser as claimed in claim 1, specifically comprises the following steps: Step 1. Processing and preparation of the substrate: sputtering a layer of insulating dielectric layer (3) on the semiconductor substrate (4), using electron beam etching technology (EBL) to etch the insulating dielectric layer (3) into a hole array structure, The etching depth is the thickness of the insulating dielectric layer (3); Step 2. Growth and preparation of semiconductor material nanowires: growing semiconductor material nanowires (203) on holes in the insulating dielectric layer (3) by chemical vapor deposition (CVD); Step 3. Sputtering coating: using a magnetron sputtering process, sputtering a layer of insulating dielectric film (202) and a layer of metal film (201) sequentially from inside to outside on the side of each semiconductor material nanowire (203); Step 4. Electrode process: using a magnetron sputtering process, a layer of ITO electrode (1) is sputtered on the top of the nanowire array (2) composed of semiconductor material nanowires (203), and on the semiconductor substrate (4) Evaporating a metal electrode (5), the metal electrode (5) is not in contact with the insulating medium layer (3); Step 5. microlens array beam synthesis: cover a piece of ITO glass on the top of the ITO electrode (1), the conductive surface of the ITO glass is in contact with the ITO electrode sputtered in step 4; on the non-conductive surface of the ITO glass, use A photolithographic process is etched into a microlens array (7).