JP6764230B2 - Manufacturing method of semiconductor nanoparticles - Google Patents

Description

The present invention relates to semiconductor nanoparticles and a method for producing the same.

A substance that has been made small (thin and thin) to about several nm to a dozen nm will exhibit physical properties different from those in the bulk state. Such phenomena / effects are called (3D to 1D) carrier confinement effect, quantum size effect, etc., and substances that exhibit such effects are called quantum dots (quantum wires, quantum wells). ..

For example, Patent Document 1 discloses semiconductor nanoparticles (quantum dots) having a luminescent core and a shell layer covering the core, and containing a nitride-based semiconductor. The band gap (light absorption wavelength and emission wavelength) of such semiconductor nanoparticles can be adjusted by changing the size (overall size).

Japanese Patent No. 4318710

A main object of the present invention is to provide semiconductor nanoparticles having a novel structure, particularly a flat plate laminated structure.

According to one aspect of the present invention, a step a) a step of dispersing seed particles in which a predetermined crystal plane is exposed in a solvent, and a step b) a quantum confinement effect on the crystal plane of the seed particles in the solvent. growing epitaxially a flat first semiconductor layer in the thickness but expressing, the step c) the first semiconductor layer after the epitaxial growth, and removing the seed particles, step d) the solvent The method for producing semiconductor nanoparticles, which comprises a step of sequentially epitaxially growing flat plate-shaped second and third semiconductor layers on the main surface of the first semiconductor layer with a thickness at which a quantum confinement effect is exhibited. Is provided.

Semiconductor nanoparticles having a flat plate laminated structure can be realized.

FIG. 1 is a schematic view showing how seed particles are produced. FIG. 2A is a schematic view showing how the seed particles are subjected to the selective light etching treatment, and FIG. 2B is a schematic perspective view showing the seed particles subjected to the selective light etching treatment. FIG. 3A is a schematic view showing how a barrier layer is grown on the exposed crystal plane of the seed particles, and FIGS. 3B and 3C are obtained by removing the barrier layer and the seed particles grown on the crystal plane of the seed particles. It is sectional drawing which shows the remaining barrier layer (single layer body). FIG. 4A is a schematic view showing how a light emitting layer grows on the main surface of the barrier layer, and FIG. 4B shows a light emitting layer (barrier layer / light emitting layer laminate) grown on the main surface of the barrier layer. It is a sectional view. FIG. 5A is a cross-sectional view showing semiconductor nanoparticles (barrier layer / light emitting layer / barrier layer laminate) according to the first embodiment, and FIG. 5B is a semiconductor nanoparticles (core / shell structure) according to a reference example. 5C is a cross-sectional view showing semiconductor nanoparticles (barrier layer / light emitting layer / barrier layer / light emitting layer / barrier layer laminate) according to the second embodiment.

Hereinafter, the method for producing semiconductor nanoparticles and the basic structure according to the examples will be described with reference to the drawings. The semiconductor nanoparticles according to the examples are seeded in a step of producing a plurality of seed particles (FIG. 1), a step of aligning the particle sizes of the seed particles and exposing a specific crystal plane (FIG. 2), and in a solvent. A step of growing a flat barrier layer on a specific crystal plane of particles and then removing seed particles (Fig. 3), and a step of laminating a flat light emitting layer on the main surface of the remaining barrier layer (FIG. 3). It is manufactured through FIG. 4) and a step (FIG. 5) of further laminating a flat plate-shaped barrier layer or the like on the main surface of the light emitting layer.

FIG. 1 shows how seed particles are produced. In the examples, the seed particles are composed of Wurtzite-type ZnOS (more specifically, ZnO _0.72 S _0.28 ) and are produced by a hot injection method. The ZnOS constituting the seed particles is not limited to the wurtzite type crystal structure, and may have a sphalerite type crystal structure. Further, the seed particles are not limited to the hot injection method, and may be produced by, for example, pulverizing a bulk seed member into fine particles (nano size) by applying ultrasonic waves or the like.

First, a quartz reaction vessel (flask) 81 is prepared. The reaction vessel 81 is provided with, for example, three opening ports 82a to 82c.

A temperature sensor (thermocouple) 83 capable of measuring the temperature of the contents in the reaction vessel 81 is inserted into the port 82a. An atmosphere replacement device capable of replacing the atmosphere in the reaction vessel 81 with, for example, an inert gas (Ar gas) is connected to the other port 82b. Further, from the other port 82c, raw materials (reagents) necessary for producing seed particles (or photoetching treatment in a subsequent step, etc.) are injected.

Further, the reaction vessel 81 is equipped with a heater 84 capable of heating the contents. A reflux device (cooler) may be attached to the port 82b together with the heater 84, for example.

The reaction solvent 11 is injected into the reaction vessel 81. The reaction solvent 11 is, for example, a mixture of tri-n-octylphosphine oxide (TOPO, 8 g) and hexadecylamine (HDA, 4 g). Subsequently, the reaction solvent 11 is heated to about 300 ° C. under an inert (Ar) gas atmosphere. At this time, it is preferable to heat the reaction solvent 11 while stirring so that the reaction solvent 11 does not have uneven heating.

Next, under an inert (Ar) gas atmosphere, diethylzinc (4.0 mmol), octylamine (2.8 mmol) and bis (trimethylsilyl) sulfide (1.2 mmol) were added to the reaction solvent 11 as reaction precursors. Added. In addition, octylamine is bubbling with oxygen for about 2 minutes in advance. As a result, a crystal nucleus of ZnO _0.72 S _0.28 is generated in the solvent 11. In the examples, ZnO _0.72 S _0.28 has a wurtzite-type crystal structure.

Immediately after injecting the reaction precursor, the solvent 11 is rapidly cooled to about 200 ° C. As a result, new crystal nuclei are not generated, and the size of the crystal nuclei is made uniform.

Subsequently, the solvent 11 is heated to about 240 ° C. and the temperature is maintained for about 3 hours. As a result, ZnO _0.72 S _0.28 grows to a particle size of about 10 nm in the solvent. The particle size of ZnO _0.72 S _0.28 is preferably 20 nm or less. Hereinafter, the series of processes up to this point will be referred to as ZnOS growth process.

Subsequently, the solvent 11 is naturally cooled to about 100 ° C., and the temperature is maintained for about 1 hour. As a result, the surface state of ZnO _0.72 S _0.28 particles is stabilized. Hereinafter, such a treatment will be referred to as a surface stabilization treatment.

Then, the solvent 11 is returned to about room temperature, butanol is added thereto, and the mixture is stirred for about 10 hours. This makes it possible to prevent agglomeration between ZnO _0.72 S _0.28 particles. Hereinafter, such a treatment will be referred to as an aggregation prevention treatment.

Next, the solvent 11 is repeatedly subjected to a centrifugation treatment (4000 rpm for 10 minutes) using dehydrated methanol and toluene alternately by a general centrifugation device (separator). As a result, unnecessary substances / materials are generally removed from the ZnO _0.72 S _0.28 particles. Hereinafter, such a process will be referred to as a purification process. Finally, the ZnO _0.72 S _0.28 particles are dispersed in methanol (particle dispersion solution 12, see FIG. 2A).

As described above, seed particles made of ZnO _0.72 S _0.28 are produced.

2A and 2B show how the seed particles have the same particle size and expose a specific crystal plane. In the embodiment, the seed particles are subjected to selective photoetching treatment.

The photoetching process refers to a process in which holes generated in seed particles by light absorption are reacted with oxygen to dissolve (etch) the seed particles themselves. By the photoetching treatment, the seed particles dispersed in the solvent can be made uniform in the particle size corresponding to the wavelength of the irradiation light. It is also possible to selectively etch a specific crystal plane of seed particles by using an appropriate etching solution.

First, the etching solution 13 is added to the particle dispersion solution 12 in which ZnO _0.72 S _0.28 particles are dispersed in methanol. The etching solution 13 is, for example, a mixture of ultrapure water and nitric acid (concentration: 61% by volume) at a volume ratio of 600: 1. Then, the solution in which the particle dispersion solution 12 and the etching solution 13 are mixed is maintained at 25 ° C., and the solution is subjected to bubbling treatment with oxygen for 5 minutes.

As shown in FIG. 2A, next, a solution in which the particle dispersion solution 12 and the etching solution 13 are mixed is housed in a closed container 85 and irradiated with light. For example, light having a wavelength of 405 nm (half width of 6 nm) is emitted from a light source 86 including a mercury lamp and a spectroscope, and the light is irradiated to a solution in which the particle dispersion solution 12 and the etching solution 13 are mixed for about 20 hours.

Next, the dispersion medium (methanol and etching solution) is replaced with water, and the seed particles are washed (washed with water). Then, the seed particles are extracted by freeze-drying. Hereinafter, such a process will be referred to as an extraction process.

As shown in FIG. 2B, after the selective photoetching treatment, the seed particles (wurtzite-type ZnO _0.72 S _0.28 particles) 21 are, for example, granular with the c-plane (crystal plane 21C) exposed. Has a shape. The particle size of the seed particles 21 or the longest width in the exposed crystal plane 21C is preferably 20 nm or less. In the examples, the particle size of the seed particles 21 or the longest width in the exposed crystal plane 21C is about 7 nm.

The crystal plane to be exposed in the seed particles (wurtzite-type ZnO _0.72 S _0.28 particles) is not limited to the c-plane, and may be any crystal plane. For example, the m-plane of wurtzite-type ZnO _0.72 S _0.28 particles can be exposed by using aqua regia as the etching solution used for the selective photoetching treatment.

3A and 3B show how a flat plate-shaped first barrier layer 22 grows on the c-plane of the seed particles 21 dispersed in the solvent. In the embodiment, the first barrier layer 22 is composed of In _0.67 Al _0.33 N, which is lattice-matched with the seed particles 21 (ZnO _0.72 S _0.28 ) and has a relatively wide (large) bandgap. Will be done. The lattice constant (a-axis direction) of ZnO _0.72 S _0.28 to In _0.67 Al _0.33 N is about 3.4Å.

As shown in FIG. 3A, first, the reaction vessel 91 is prepared. The reaction vessel 91 is made of stainless steel on the outside and Hastelloy on the inside. The reaction vessel 91 is provided with at least two air supply ports 92a and 92b and an exhaust port 92c.

Air supply port 92a, the 92b, respectively via a valve, for example, is connected to an Ar gas supply source and _{N 2} gas supply source, the air supply port 92a, into the reaction vessel 91 from 92b, Ar gas and _{N 2} Gas can be supplied. Further, an exhaust pump is connected to the exhaust port 92c via a valve, and the atmosphere (gas) in the reaction vessel 91 can be exhausted. By adjusting the valves, partial pressures of, in particular N ₂ gas for various gases in the reaction vessel 91 can be precisely controlled.

Further, a temperature sensor 93, a heater 94, a stirring mechanism 95 and the like are attached to the reaction vessel 91. The temperature sensor 93 can measure the temperature of the contents in the reaction vessel 91. The heater 94 can heat the contents. The stirring mechanism 95 (rotary blade) can stir the contents.

The seed particles (wurtzite-type ZnO _0.72 S _0.28 particles with exposed c-plane) prepared above are dispersed in diphenyl ether, and the diphenyl ether (20 ml) is injected into the reaction vessel 91. Subsequently, aluminum iodide (0.20 mmol), indium iodide (0.40 mmol), sodium amide (12.8 mmol) and a capping agent (1.0 mmol of hexadecanethiol and 0.6 mol of zinc stearate) were placed in the reaction vessel 91. ) Is injected (first mixed solution 14). Then, the partial pressure of nitrogen in the reaction vessel 91 is set to 1500 Torr, the first mixed solution 14 is heated to 225 ° C., and the temperature is maintained for about 20 minutes. Hereinafter, such a process will be referred to as an InAlN growth process. In addition, zinc may be mixed with InAlN from zinc stearate which is a capping agent, and this is also referred to as InAlN.

As shown in FIG. 3B, by such a treatment, the In _0.67 Al _0.33 N layer (first barrier layer) 22 epitaxially grows on the exposed surface (c surface) of the seed particles 21 dispersed in the solvent. .. Since the first barrier layer 22 grows on the c-plane of the seed particles 21, the main surface (exposed surface) of the first barrier layer 22 also constitutes the c-plane (crystal plane 22C).

The thickness of the first barrier layer 22 is about 2 nm. This thickness is a thickness at which the quantum confinement effect is sufficiently exhibited. The thickness of the first barrier layer 22 can be controlled by adjusting the heating time of the first mixed solution 14.

Then, the seed particles on which the first barrier layer is laminated are sequentially subjected to a surface stabilization treatment, an aggregation prevention treatment, and a purification treatment. Finally, the seed particles containing the first barrier layer are dispersed in methanol.

FIG. 3C shows how the seed particles 21 are removed to leave the first barrier layer 22. The seed particles 21 are removed, for example, by etching.

The etching solution is added to methanol in which the seed particles containing the first barrier layer are dispersed. As the etching solution, for example, a mixture of pure water and hydrochloric acid (concentration: 36% by volume) at a volume ratio of 100: 1 (dilute hydrochloric acid) is used. As a result, the seed particles 21 are removed, leaving only the flat first barrier layer 22.

Subsequently, the dispersion medium (methanol and etching solution) is replaced with water, and the monolayer of the first barrier layer is washed (washed with water). Then, the monolayer of the first barrier layer is extracted (that is, an extraction process is performed) by freeze-drying.

4A and 4B show how a flat plate-shaped first light emitting layer 23 grows on the main surface of the first barrier layer 22 in a solvent. In the embodiment, the first light emitting layer 23 is lattice-matched with the first barrier layer 22 (In _0.67 Al _0.33 N), and the band gap is relatively narrow (small) In _0.60 Ga _0.40. It is composed of N. The first light emitting layer 23 can be grown by using the equipment / apparatus (FIG. 3A) in which the first barrier layer 22 is produced.

As shown in FIG. 4A, first, the monolayer of the first barrier layer prepared above is dispersed in diphenyl ether, and the diphenyl ether (20 ml) is injected into the reaction vessel 91. Further, in the reaction vessel 91, gallium iodide (0.24 mmol), indium iodide (0.36 mmol), sodium amide (12.8 mmol) and a capping agent (1.0 mmol of hexadecanethiol and 0.6 mol of zinc stearate). Is injected (second mixed solution 15). Then, the partial pressure of nitrogen in the reaction vessel 91 is set to 1500 Torr, the second mixed solution 15 is heated to 225 ° C., and the temperature is maintained for about 80 minutes. Hereinafter, such a process will be referred to as an InGaN growth process. In addition, zinc may be mixed with InGaN from zinc stearate, which is a capping agent, and this is also referred to as InGaN.

As shown in FIG. 4B, by such a treatment, the In _0.60 Ga _0.40 N layer (first light emitting layer) 23 is epitaxially grown on the main surface (c surface) of the first barrier layer 22. After that, the laminated body of the first barrier layer / first light emitting layer is subjected to surface stabilization treatment, aggregation prevention treatment, purification treatment and extraction treatment.

The thickness of the first light emitting layer 23 is about 4 nm. This thickness is a thickness at which the quantum confinement effect is sufficiently exhibited. The thickness of the light emitting layer 23 can be adjusted by changing the heating time of the second mixed solution 15. The thickness of the light emitting layer may be adjusted while monitoring the wavelength of the light (fluorescence) emitted from the light emitting layer.

As shown in FIG. 4A, for example, the excitation light of a predetermined wavelength emitted from the light source 97 is irradiated to the second mixed solution 15 (the light emitting layer dispersed therein) through the optical fiber 96i. The light emitting layer dispersed in the second mixed solution 15 absorbs the excitation light and emits light having a wavelength corresponding to the layer thickness. The light emitted from the light emitting layer is introduced into the photodetector 98 having a spectroscopic function through the optical fiber 96o.

When the second mixed solution 15 is heated, the thickness of the light emitting layer increases. As the thickness of the light emitting layer increases in the range where the quantum confinement effect is exhibited, the wavelength of the light emitted from the light emitting layer shifts to the longer wavelength side. When the photodetector 98 detects light of a desired wavelength, the heating of the second mixed solution 15 is stopped. The thickness of the light emitting layer can also be controlled by such a method.

FIG. 5A shows how a flat plate-shaped second barrier layer 24 grows on the main surface of the first light emitting layer 23. The previously prepared laminate of the first barrier layer 22 / first light emitting layer 23 is subjected to InAlN growth treatment again, and the main surface (c surface) of the first light emitting layer 23 is subjected to the second barrier layer (In _{0. 67} Al _0.33 N layer) 24 is epitaxially grown. The thickness of the second barrier layer 24 is about 2 nm. As a result, semiconductor nanoparticles 20a (first embodiment) in which the first barrier layer 22, the first light emitting layer 23, and the second barrier layer 24 are sequentially laminated are produced. After that, the semiconductor nanoparticles 20a (layered body of the first barrier layer 22 / first light emitting layer 23 / second barrier layer 24) are subjected to surface stabilization treatment, aggregation prevention treatment, purification treatment, and extraction treatment.

The first barrier layer 22 and the second barrier layer 24 have a wider bandgap than the first light emitting layer 23, and the first light emitting layer 23 exhibits a quantum confinement effect (one-dimensional quantum confinement effect) at least in the thickness direction. .. In the embodiment, the thickness of the first light emitting layer 23 is about 4 nm, and the wavelength of the light emitted from the first light emitting layer 23 is about 550 nm.

The size of the first light emitting layer 23 (or the first and second barrier layers 22, 24) in the plane direction is defined by the size of the crystal plane 21C (FIG. 2B) of the seed particles 21. The thickness of the first light emitting layer 23 can be adjusted by changing the heating time in the InGaN growth treatment. That is, the size of the first light emitting layer 23 can be adjusted one-dimensionally (only in the thickness direction). Since the longest width of the seed particles 21 in the crystal plane 21C is preferably 20 nm or less, the maximum width of the first light emitting layer 23 (or the first and second barrier layers 22, 24) in the in-plane direction. Is also preferably 20 nm or less.

FIG. 5B shows semiconductor nanoparticles 20p according to a reference example. The semiconductor nanoparticles 20p are configured to include a spherical core 23c having light emission and a shell layer 24s that covers the core 23c and has a band gap wider than that of the core 23c. It is assumed that the (three-dimensional) quantum confinement effect is exhibited in the core 23c. In the spherical core 23c, its size is difficult to adjust one-dimensionally, and generally, the particle size (diameter) is changed to adjust it three-dimensionally. It can be considered that the light emitting layer according to the example corresponds to the core according to the reference example, and the barrier layer according to the example corresponds to the shell layer according to the reference example.

In the embodiment, the size of the light emitting layer can be adjusted one-dimensionally (only in the thickness direction). Therefore, it is relatively easy to accurately adjust the size of the light emitting layer, and it is possible to more accurately control the band gap or the emission wavelength of the light emitting layer. On the other hand, in the comparative example, the size of the core can be adjusted only three-dimensionally. Therefore, it is relatively difficult to accurately adjust the size of the core, and it is difficult to accurately control the band gap or emission wavelength of the core.

FIG. 5C shows the semiconductor nanoparticles 20b (second embodiment) in which the flat plate-shaped second light emitting layer 25 and the third barrier layer 26 are further laminated on the semiconductor nanoparticles 20a (FIG. 5A). The laminated body (first flat plate laminated structure) of the first barrier layer 22 / first light emitting layer 23 / second barrier layer 24 constitutes one light emitting unit, and the second barrier layer 24 / second light emitting layer 25 / The laminated body of the third barrier layer 26 (second flat plate laminated structure) constitutes another light emitting unit.

The semiconductor nanoparticles 20b are obtained by subjecting the semiconductor nanoparticles 20a (a laminate of the first barrier layer 22 / first light emitting layer 23 / second barrier layer 24) to InGaN growth treatment and InAlN growth treatment again to perform a second barrier. It is produced by epitaxially growing a second light emitting layer (In _0.60 Ga _0.40 N layer) 25 and a third barrier layer (In _0.67 Al _0.33 N layer) 26 on the main surface of the layer 24. Can be done. In addition, surface stabilization treatment, aggregation prevention treatment, purification treatment, and extraction treatment may be appropriately performed.

The second barrier layer 24 and the third barrier layer 26 have a wider bandgap than the second light emitting layer 25, and the second light emitting layer 25 exhibits a quantum confinement effect (one-dimensional quantum confinement effect) at least in the thickness direction. .. When the thickness of the second light emitting layer 25 is the same as the thickness of the first light emitting layer 23 (4 nm), the emission intensity (wavelength 550 nm) of the semiconductor nanoparticles 20b is ideally the semiconductor nanoparticles 20a (FIG. 5A). ) Can be doubled. When the thickness of the second light emitting layer 25 is different from the thickness of the first light emitting layer 23 (4 nm) (for example, 5 nm), light having a plurality of wavelengths (wavelengths 550 nm and 630 nm) is emitted from the semiconductor nanoparticles 20b. Can be released.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited thereto. For example, the timing for removing the seed particles may be at least after the first barrier layer has been grown, for example, after the first light emitting layer has been grown or after the second barrier layer has been grown. It doesn't matter. Further, semiconductor nanoparticles having a flat plate laminated structure including three or more light emitting layers may be produced.

Further, the InAlN layer (barrier layer) or the InGaN layer (light emitting layer) may be made of another material. For example, the InGaN layer (light emitting layer) may be replaced with the ZnOS layer.

The combination of the InAlN layer (barrier layer) and the InGaN layer (light emitting layer) has a type I band offset structure. The type I band offset structure has a structure in which a layer with a narrow bandgap (InGaN layer) is sandwiched between layers with a wide bandgap (InAlN layer), and carrier recombination can occur inside the layer with a narrow bandgap. On the other hand, the combination of the InAlN layer and the ZnOS layer has a type II band offset structure. Type II band offset structures can cause carrier recombination between adjacent layers.

Semiconductor nanoparticles in which the InGaN layer (light emitting layer) is replaced with a ZnOS layer, that is, semiconductor nanoparticles composed of alternating layers of InAlN layers and ZnOS layers (modification example) are produced as follows. First, a plurality of seed particles are prepared (FIG. 1) in the same manner as the semiconductor nanoparticles according to the examples, the particle sizes of the seed particles are made uniform, and a specific crystal plane is exposed (FIG. 2), and the seeds are seeded in a solvent. A flat plate-like InAlN layer is grown on a specific crystal plane of the particles, and then the seed particles are removed (FIG. 3).

Subsequently, the remaining single layer of the InAlN layer is subjected to ZnOS growth treatment. That is, the reaction precursors (diethylzinc, octylamine and bis (trimethylsilyl) sulfide) are added to methanol in which the monolayer of the InAlN layer is dispersed, then rapidly cooled to 200 ° C. and heated to 240 ° C. again. When this temperature is maintained for about 50 minutes, a ZnO _0.72 S _0.28 layer having a thickness of about 5 nm is epitaxially grown on the main surface of the InAlN layer. When this temperature is maintained for about 70 minutes, a ZnO _0.72 S _0.28 layer having a thickness of about 7 nm grows epitaxially. After that, the laminated body of the InAlN layer / ZnOS layer is subjected to surface stabilization treatment, aggregation prevention treatment, purification treatment and extraction treatment.

Subsequently, the laminate of the InAlN layer / ZnOS layer is subjected to the InAlN growth treatment again to perform a modification of the semiconductor nanoparticles according to the first embodiment (FIG. 5A) (first InAlN layer / second ZnOS layer / second InAlN layer). (1st modified example) can be obtained. After that, by further performing ZnOS growth treatment and InAlN growth treatment, a modified example of the semiconductor nanoparticles (first InAlN layer / first ZnOS layer / second InAlN layer / second ZnOS layer / third InAlN layer) according to the second embodiment (FIG. 5C). (2nd modified example) can be obtained. In addition, surface stabilization treatment, aggregation prevention treatment, purification treatment, and extraction treatment may be appropriately performed.

When the thickness of the first and second InAlN layers is about 2 nm and the thickness of the first ZnOS layer is about 5 nm, the emission wavelength of the semiconductor nanoparticles according to the first modification is about 2.5 μm. When the thickness of the first ZnOS layer is about 7 nm, the emission wavelength of the semiconductor nanoparticles according to the first modification is about 2.9 μm. Further, in the semiconductor nanoparticles according to the second modification, for example, when the thickness of the first to third InAlN layers is 2 nm, the thickness of the first ZnOS layer is 5 nm, and the thickness of the second ZnOS layer is 7 nm, the semiconductor nanoparticles. Can emit light (infrared rays) of 2.5 μm and 2.9 μm.

This time, the case of ZnOS particles as seed particles has been described, but Se may be included. For example, if a part or all of the sulfur-containing material bis (trimethylsilyl) sulfide is replaced with the selenium-containing material tri-n-octylphosphine serenide as the material for the seed particles, ZnOSSe or ZnOSe can be prepared by the same procedure. There will be.

Other than that, it will be obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

11 to 15 ... solvent, 20 ... semiconductor nanoparticles, 21 ... seed particles, 22 ... first barrier layer, 23 ... first light emitting layer, 24 ... second barrier layer, 25 ... second light emitting layer, 26 ... third barrier Layer, 81 ... Reaction vessel (flask), 82 ... Port, 83 ... Temperature sensor (thermocouple), 84 ... Heater, 85 ... Sealed container, 86 ... Light source, 91 ... Reaction vessel, 92 ... Air supply port / exhaust port, 93 ... Temperature sensor (thermocouple), 94 ... Heater, 95 ... Stirring mechanism (rotary blade), 96 ... Optical fiber, 97 ... Light source, 98 ... Photodetector.

Claims (5)

Step a) A step of dispersing seed particles in which a predetermined crystal face is exposed is dispersed in a solvent.
Step b) A step of epitaxially growing a flat plate-shaped first semiconductor layer having a thickness at which the quantum confinement effect is exhibited on the crystal plane of the seed particles in the solvent.
Step c) A step of epitaxially growing the first semiconductor layer and then removing the seed particles.
Step d) A step of sequentially epitaxially growing flat plate-shaped second and third semiconductor layers on the main surface of the first semiconductor layer in the solvent with a thickness at which the quantum confinement effect is exhibited.
A method for producing semiconductor nanoparticles having. The method for producing semiconductor nanoparticles according to claim 1, wherein the seed particles contain ZnOS. The method for producing semiconductor nanoparticles according to claim 2, wherein the crystal plane of the seed particles is the c-plane. The method for producing semiconductor nanoparticles according to claim 3, wherein in the step b), the first semiconductor layer contains a nitride semiconductor and grows while exposing the c-plane. The method for producing semiconductor nanoparticles according to claim 4, wherein in the step d), the second and third semiconductor layers each contain a nitride semiconductor and grow while exposing the c-plane.

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