Quantum dot white light LED, preparation method thereof and display device

Abstract

The invention discloses a quantum dot white light LED, a preparation method thereof and a display device. The white light LED comprises a substrate, a gallium nitride buffer layer, an n-type gallium nitride layer, a quantum dot layer and a p-type gallium nitride layer, wherein the gallium nitride buffer layer, the n-type gallium nitride layer, the quantum dot layer and the p-type gallium nitride layer are sequentially arranged on one side of the substrate in a stacked mode. And a first electrode and a second electrode; the quantum dot layer comprises a quantum dot matrix composed of a plurality of quantum dot cones; the quantum dot cones comprise a red quantum dot cone, a blue quantum dot cone and a green quantum dot cone; the cone of the blue quantum dot is In < x > Ga < 1-x > N, the cone of the red quantum dot is Al < y > Ga < z > In < 1-y-z > P, the cone of the green quantum dot is GaP, x is 0.1-0.25, y is 0.15-0.3, and z is 0.15-0.3. The three-primary-color quantum dots are adopted for light mixing to obtain white light, and the influence of lattice mismatch between different materials can be reduced; by adopting the quantum dot cone, the light-emitting surface is an inclined surface, and the light extraction efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of display, and particularly relates to a quantum dot white light LED, a preparation method thereof, and a display device. Background Art

[0002] White light LEDs (light emitting diodes) have been widely used in lighting in recent years. Compared with the tungsten filaments of incandescent lamps, LEDs can directly generate photons through carrier recombination by relying on the PN junctions inside them, and have the advantages of long luminous life, low energy consumption, high photoelectric conversion efficiency, etc. There are two ways to realize white light LEDs: LED excitation of multicolor phosphors and multi-primary color LEDs. Monochromatic LED-excited phosphor-based white light LEDs utilize the principle of photoluminescence and achieve white light by using ultraviolet or blue LEDs to excite multicolor phosphors for composite light emission. Therefore, the light emitted by them contains more ultraviolet light and blue light, which is harmful to human skin and eyes. Multi-primary color LEDs have a more extensive and comprehensive light emission band and are a direction worthy of in-depth research.

[0003] LED devices usually use III-V group compound materials. By changing the alloy materials of the components, the bandgap width modulation can be achieved, covering the entire visible light band. Especially for blue LEDs, their InGaN structure has obtained a relatively high luminous efficiency. However, as the luminous wavelength increases, the luminous efficiency of nitrides decreases sharply, and the luminous efficiency of red nitride LEDs is even less than 1%. For example, the methods to obtain white light LEDs in related technologies are as follows: 1. Using a blue LED to excite a yellow-red phosphor, with a blue light wavelength of 450-470 nm, and this light source excites a mixed phosphor of yellow powder YAG:Ce 3+ and red powder CaAlSiN3:Eu 2+ to form white light by mixing. 2. Using multi-chip synthesis to form white light LEDs. The most common is to use RGB three-color mixing light. According to a certain light intensity ratio, it has a large color temperature change space. However, the performances of the three chips are different, the control circuit design is complex, and the cost is relatively high. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a quantum dot white light LED, a preparation method thereof, and a display device. The technical problems to be solved by the present invention are achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a quantum dot white light LED, including a substrate, a gallium nitride buffer layer, an n-type gallium nitride layer, a quantum dot layer, and a p-type gallium nitride layer that are sequentially stacked on one side of the substrate; and a first electrode electrically connected to the n-type gallium nitride layer and a second electrode electrically connected to the p-type gallium nitride layer;

[0006] The quantum dot layer includes a quantum dot lattice composed of a plurality of quantum dot cones, and the bottom surface of the quantum dot cone is closer to the n-type gallium nitride layer than the vertex of the quantum dot cone;

[0007] The quantum dot cones include red quantum dot cones, blue quantum dot cones and green quantum dot cones;

[0008] The blue quantum dot cone is In x Ga 1-x N, the red quantum dot cone is Al y Ga z In 1-y-z P, the green quantum dot cone is GaP, where x is 0.1 - 0.25, y is 0.15 - 0.3, and z is 0.15 - 0.3.

[0009] In one embodiment of the present invention, among the total number of quantum dot cones in the quantum dot layer, the blue light quantum dot cones account for 40 - 60% of the total, the green light quantum dot cones account for 30 - 40% of the total, and the red light quantum dot cones account for 30 - 40% of the total.

[0010] In one embodiment of the present invention, the orthographic projection area of the blue quantum dot cone on the substrate is 35 - 65 nm 2 , the orthographic projection area of the red quantum dot cone on the substrate is 100 - 150 nm 2 , the orthographic projection area of the green quantum dot cone on the substrate is 65 - 100 nm 2 .

[0011] In one embodiment of the present invention, the thickness of the quantum dot layer is 8 - 10 nm.

[0012] In one embodiment of the present invention, the substrate is a gallium oxide substrate or a C-plane sapphire substrate.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned quantum dot white light LED, and the method includes the following steps:

[0014] S10. Obtain a substrate, and sequentially form a gallium nitride buffer layer and an n-type gallium nitride layer on one side of the substrate;

[0015] S20. Respectively form a red quantum dot preform lattice, a green quantum dot preform lattice and a blue quantum dot preform lattice on the side of the n-type gallium nitride layer away from the substrate; among them, the blue quantum dot preform is In x Ga 1-x N, the red quantum dot preform is Al y Ga z In 1-y-zP, where the green quantum dot preform is GaP, x is from 0.1 to 0.25, y is from 0.15 to 0.3, and z is from 0.15 to 0.3;

[0016] S30: Use a photolithography process to etch each red quantum dot preform, green quantum dot preform, and blue quantum dot preform to form red quantum dot cones, green quantum dot cones, and blue quantum dot cones, thereby obtaining a quantum dot layer;

[0017] S40: Form a p-type gallium nitride layer on the side of the quantum dot layer away from the substrate, form a first electrode on the side of the n-type gallium nitride layer away from the substrate, and form a second electrode on the side of the p-type gallium nitride layer away from the substrate, thereby obtaining a quantum dot white LED.

[0018] In an embodiment of the present invention, in step S20, forming a red quantum dot preform lattice, a green quantum dot preform lattice, and a blue quantum dot preform lattice on the side of the n-type gallium nitride layer away from the substrate includes:

[0019] Form a red quantum dot layer on the side of the n-type gallium nitride layer away from the substrate, and use inductively coupled plasma etching technology to pattern the red quantum dot layer to obtain a red quantum dot preform lattice;

[0020] Form a green quantum dot layer on the side of the n-type gallium nitride layer and the red quantum dot preform away from the substrate, and use inductively coupled plasma etching technology to pattern the green quantum dot layer to obtain a green quantum dot preform lattice;

[0021] Form a blue quantum dot layer on the side of the n-type gallium nitride layer, the red quantum dot preform, and the green quantum dot preform away from the substrate, and use inductively coupled plasma etching technology to pattern the blue quantum dot layer to obtain a blue quantum dot preform lattice.

[0022] In an embodiment of the present invention, in steps S20 and S30, the bottom area of the red quantum dot preform on the side close to the n-type gallium nitride layer is equal to the bottom area of the red quantum dot cone on the side close to the n-type gallium nitride layer;

[0023] The bottom area of the green quantum dot preform on the side close to the n-type gallium nitride layer is equal to the bottom area of the green quantum dot cone on the side close to the n-type gallium nitride layer;

[0024] The bottom area of the blue quantum dot preform on the side close to the n-type gallium nitride layer is equal to the bottom area of the blue quantum dot cone on the side close to the n-type gallium nitride layer.

[0025] In one embodiment of the present invention, the bottom surface of the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform on the side close to the n-type gallium nitride layer is any one of a square, a rectangle, or a circle;

[0026] In step S30, the red quantum dot cone, the green quantum dot cone, and the blue quantum dot cone are pyramids or cones.

[0027] In a third aspect, the present invention provides a display device, including a display module and a backlight module, and the backlight module includes the above-mentioned quantum dot white LED.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The quantum dot white LED provided by the present invention sets three primary color quantum dots (red quantum dots, green quantum dots, and blue quantum dots) on the same substrate, with high integration, no need for additional synthesis of phosphors, and a simple control circuit, and a convenient and efficient white LED can be obtained.

[0030] 2. The present invention uses three primary color quantum dots for mixing light to obtain white light. The structural characteristics of the quantum dots can reduce the influence of lattice mismatch between different materials; by using quantum dot cones, the light-emitting surface is an inclined plane, which improves the light extraction efficiency.

[0031] 3. The manufacturing process and materials of the quantum dot white LED provided by the present invention are simple and have good repeatability. It is of great significance to the development of lighting technology, and it is expected to realize a single-chip white LED, which can play an important role in a variety of working environments, such as in the fields of miniature white light sources and screen backlights, and has good application prospects.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic cross-sectional structure diagram of a quantum dot white LED provided by an embodiment of the present invention;

[0034] Figure 2 is a schematic preparation process diagram of a quantum dot white LED provided by an embodiment of the present invention;

[0035] Figure 3 is a schematic cross-sectional preparation process diagram of a quantum dot white LED provided by an embodiment of the present invention;

[0036] Figure 4 is a schematic cross-sectional preparation process diagram of a quantum dot white LED provided by an embodiment of the present invention;

[0037] Figure 5It is a schematic cross-sectional view of the preparation process of a quantum dot white LED provided by an embodiment of the present invention;

[0038] Figure 6 It is a schematic cross-sectional view of the preparation process of a quantum dot white LED provided by an embodiment of the present invention;

[0039] Figure 7 It is a schematic cross-sectional view of the preparation process of a quantum dot white LED provided by an embodiment of the present invention;

[0040] Figure 8 It is a schematic cross-sectional view of the preparation process of a quantum dot white LED provided by an embodiment of the present invention;

[0041] Figure 9 It is a schematic cross-sectional view of the preparation process of a quantum dot white LED provided by an embodiment of the present invention;

[0042] Figure 10 It is a top view of a quantum dot array in a quantum dot white LED provided by an embodiment of the present invention;

[0043] Figure 11 It is another top view of a quantum dot array in a quantum dot white LED provided by an embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1 - Substrate; 2 - Gallium nitride buffer layer; 3 - n-type gallium nitride layer; 4 - p-type gallium nitride layer; 5 - First electrode; 6 - Second electrode; RQD - Red quantum dot; BQD - Blue quantum dot; GQD - Green quantum dot. Detailed implementation manners

[0046] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the quantum dot white LED, its preparation method, and display device proposed according to the present invention will be described in detail below with reference to the accompanying drawings and specific implementation manners.

[0047] The foregoing and other technical contents, features, and effects of the present invention can be clearly presented in the following detailed description in conjunction with the accompanying drawings. Through the description of the specific implementation manners, a more in-depth and specific understanding of the technical means and effects adopted by the present invention to achieve the predetermined purpose can be obtained. However, the accompanying drawings are only for reference and illustration, and are not used to limit the technical solution of the present invention.

[0048] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant is intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements includes not only those elements but also other elements not expressly listed.

[0049] In the related art, the chemical properties of the phosphor are not stable enough, and it is easy to degenerate at a relatively high junction temperature, resulting in a decrease in luminous intensity, and it is not easy to synthesize, so that the performance of the white LED prepared by using the phosphor is unstable. In addition, when using multi-chip synthesis of white LEDs, the mixing control circuit is relatively complex, the multi-chip integration degree is not high, and the color rendering index is insufficient. Quantum dots have high research value because of their special luminescence characteristics. When the size is several nanometers, the energy levels of the semiconductor are no longer quasi-continuous but discrete. Affected by the quantum confinement effect, high-luminance purity and high-efficiency LEDs can be obtained.

[0050] Based on the above problems and the characteristics of quantum dots, an embodiment of the present invention provides a quantum dot white LED. Refer to Figure 1 , the quantum dot white LED includes a substrate 1, a gallium nitride buffer layer 2, an n-type gallium nitride layer 3, a quantum dot layer, and a p-type gallium nitride layer 4 that are sequentially stacked on one side of the substrate 1; and a first electrode 5 electrically connected to the n-type gallium nitride layer 3 and a second electrode 6 electrically connected to the p-type gallium nitride layer 4; the quantum dot layer includes a quantum dot array composed of a plurality of quantum dot cones, and the bottom surface of the quantum dot cone is closer to the n-type gallium nitride layer 3 than the vertex of the quantum dot cone; the quantum dot cone includes a red quantum dot cone, a blue quantum dot cone, and a green quantum dot cone; the blue quantum dot cone is In x Ga 1-x N, the red quantum dot cone is Al y Ga z In 1-y-z P, the green quantum dot cone is GaP, where x is 0.1 to 0.25, y is 0.15 to 0.3, and z is 0.15 to 0.3.

[0051] In this embodiment, red, blue, and green quantum dot cones in the quantum dot layer emit red, blue, and green light respectively for mixed light to obtain white light, thereby obtaining a white LED with high luminous purity and high luminous efficiency. By setting the red quantum dots, blue quantum dots, and green quantum dots all in a cone structure, the loss of the emitted light is reduced and the light extraction rate is increased. In addition, the quantum dots are small in size and their volume is much smaller than the critical thickness, so the strain energy generated by lattice mismatch can be released through elastic deformation without generating dislocations, reducing the lattice mismatch, and thereby improving the performance and service life of the quantum dot white LED.

[0052] In this embodiment, the blue quantum dot cone is In x Ga 1-x N, where x is from 0.1 to 0.25. Within the range of the x value, the emission wavelength of the InGaN quantum dots will vary, but they are all within the blue light wavelength range. In actual use, an appropriate x value can be selected according to needs. For example, the blue quantum dot cone can be In 0.1 Ga 0.9 N, or In 0.15 Ga 0.85 N, or In 0.2 Ga 0.8 N, or In 0.25 Ga 0.75 N.

[0053] The red quantum dot cone is Al y Ga z In 1-y-z P, where y is from 0.15 to 0.3 and z is from 0.15 to 0.3. Within the range of the y and z values, the emission wavelength of the AlGaInP quantum dots will vary, but they are all within the red light wavelength range. In actual use, appropriate y and z values can be selected according to needs. For example, the red quantum dot cone can be Al 0.15 Ga 0.15 In 0.7 P, or Al 0.15 Ga 0.25 In 0.6 P, or Al 0.15 Ga 0.3 In 0.55 P, or Al 0.25 Ga 0.15 In 0.6 P, or Al 0.25 Ga 0.25 In 0.5 P, or Al 0.25 Ga 0.3 In 0.45 P, or Al0.3 Ga 0.15 In 0.55 P, or Al 0.3 Ga 0.25 In 0.45 P, or Al 0.3 Ga 0.3 In 0.4 P.

[0054] In one example, among the total number of quantum dot cones in the quantum dot layer, the blue light quantum dot cones account for 40 - 60% of the total, the green light quantum dot cones account for 30 - 40% of the total, and the red light quantum dot cones account for 30 - 40% of the total. Further, the blue light quantum dot cones account for 50% of the total, the green light quantum dot cones account for 25% of the total, and the red light quantum dot cones account for 25% of the total.

[0055] In one example, the orthographic projection area of the blue quantum dot cone on the substrate 1 is 35 - 65 nm 2 , the orthographic projection area of the red quantum dot cone on the substrate 1 is 100 - 150 nm 2 , and the orthographic projection area of the green quantum dot cone on the substrate 1 is 65 - 100 nm 2 . The orthographic projection area mentioned here can be understood as the area of the bottom surface of the corresponding quantum dot cone close to the n-type gallium nitride layer. For example, the orthographic projection area of the blue quantum dot cone on the substrate 1 is the area of the bottom surface of the blue quantum dot cone close to the n-type gallium nitride layer. In one example, the thickness of the quantum dot layer is 8 - 10 nm. That is to say, the quantum dot cones in the white light LED provided by the present invention are nanoscale in both height and bottom surface size. In this way, on the one hand, the small-sized quantum dots enable strain relaxation, and the strain generated by lattice mismatch can be released through elastic deformation without generating dislocations, and the contact area between the quantum dots and the surrounding materials is small, and the lattice distortion at the interface is limited within the nanoscale and long-range defects will not be formed. On the other hand, quantum dots of multiple materials are formed on the same substrate 1, and the nanoscale size enables materials with different lattice constants to coexist without the need to strictly match the substrate, broadening the selection of the substrate 1.

[0056] In one example, the substrate 1 is a gallium oxide substrate or a C-plane sapphire substrate.

[0057] The present invention also provides a preparation method for the above-mentioned quantum dot white light LED, see Figure 2 , including the following steps:

[0058] S10. Obtain the substrate 1, as Figure 3 shown, sequentially form a gallium nitride buffer layer 2 and an n-type gallium nitride layer 3 on one side of the substrate 1.

[0059] In one example, in step S10, obtaining the substrate 1 includes cleaning and drying the substrate. The substrate 1 can be a β-Ga2O3(010) substrate (where 010 is the crystal plane index of gallium oxide crystal), or a c-plane sapphire substrate.

[0060] In one example, in step S10, forming the gallium nitride buffer layer 2 can be as follows: on one side of the substrate 1, using the MOCVD (Metal-organic Chemical Vapor Deposition, a new type of vapor phase epitaxial growth technology) process, setting the reaction chamber temperature to 1120 °C and maintaining the pressure at 70 Torr, introducing ammonia with a flow rate of 2500 sccm and a gallium source with a flow rate of 200 sccm, and the growth thickness of the gallium nitride buffer layer 2 is 450 nm.

[0061] In one example, in step S10, forming the n-type gallium nitride layer 3 can be as follows: on the side of the gallium nitride buffer layer 2 away from the substrate 1, using the MOCVD process, setting the reaction chamber temperature to 1150 °C and maintaining the pressure at 70 Torr, introducing ammonia with a flow rate of 2500 sccm, a gallium source with a flow rate of 200 sccm, and a silicon source with a flow rate of 45 sccm, and the growth thickness of the n-type gallium nitride layer 3 is 550 nm.

[0062] S20. Respectively form a red quantum dot preform lattice, a green quantum dot preform lattice, and a blue quantum dot preform lattice on the side of the n-type gallium nitride layer 3 away from the substrate 1, see Figures 3 - 8 ; among them, the blue quantum dot preform is In x Ga 1-x N, the red quantum dot preform is Al y Ga z In 1-y-z P, the green quantum dot preform is GaP, x is 0.1 - 0.25, y is 0.15 - 0.3, and z is 0.15 - 0.3.

[0063] S30. As Figure 9 shown, use photolithography to etch each red quantum dot preform, green quantum dot preform, and blue quantum dot preform to form red quantum dot cones, green quantum dot cones, and blue quantum dot cones, and obtain a quantum dot layer.

[0064] In one example, in steps S20 and S30, the bottom area of the red quantum dot preform close to the side of the n-type gallium nitride layer 3 is equal to the bottom area of the red quantum dot cone close to the side of the n-type gallium nitride layer 3; the bottom area of the green quantum dot preform close to the side of the n-type gallium nitride layer 3 is equal to the bottom area of the green quantum dot cone close to the side of the n-type gallium nitride layer 3; the bottom area of the blue quantum dot preform close to the side of the n-type gallium nitride layer 3 is equal to the bottom area of the blue quantum dot cone close to the side of the n-type gallium nitride layer 3.

[0065] S40, as Figure 9 shown, a p-type gallium nitride layer 4 is formed on the side of the quantum dot layer away from the substrate 1.

[0066] In one example, in step S40, forming the p-type gallium nitride layer 4 may be: on the side of the quantum dot layer away from the substrate 1, using the MOCVD process, setting the reaction chamber temperature to 1150 °C, maintaining the pressure at 70 Torr, introducing ammonia with a flow rate of 2500 sccm, a gallium source of 200 sccm, and a magnesium source of 150 sccm, the growth thickness of the p-type gallium nitride layer 4 is 700 nm, and then the temperature is reduced to 980 °C, and only H2 is introduced for annealing for 15 min.

[0067] S50, a first electrode 5 is formed on the side of the n-type gallium nitride layer 3 away from the substrate 1, and a second electrode 6 is formed on the side of the p-type gallium nitride layer 4 away from the substrate 1 to obtain a quantum dot white light LED.

[0068] In one example, in step S50, forming the first electrode 5 and the second electrode 6 may be: using the metal sputtering process, depositing the first electrode 5 on the side of the n-type gallium nitride layer 3 away from the substrate 1, depositing the second electrode 6 on the side of the p-type gallium nitride layer 4 away from the substrate 1, and the thicknesses of the first electrode 5 and the second electrode 6 are 1000 nm.

[0069] In one embodiment of the present invention, in step S20, forming the red quantum dot preform lattice, the green quantum dot preform lattice, and the blue quantum dot preform lattice on the side of the n-type gallium nitride layer 3 away from the substrate 1 includes:

[0070] Step S21, as Figure 3 and Figure 4 shown, a red quantum dot layer is formed on the side of the n-type gallium nitride layer 3 away from the substrate 1, and the red quantum dot layer is patterned using inductively coupled plasma etching technology to obtain a red quantum dot preform lattice.

[0071] Exemplarily, in step S21, forming the red quantum dot preform lattice may be as follows: on the side of the n-type gallium nitride layer 3 away from the substrate 1, using the MBE (molecular beam epitaxy) process, heating the substrate 1 to 550 °C, loading high-purity Al source, Ga source, In source, and P source materials, precisely controlling the beam currents of Al, Ga, In, and P to achieve the required Al y Ga z In 1-y-z P component (where y = 0.25, z = 0.25), growing a red quantum dot layer with a thickness of 8 - 10 nm; then growing a SiO2 mask for dry etching on the red quantum dot layer, patterning the mask using photolithography, etching the red quantum dot layer using ICP (inductively coupled plasma) etching technology to form a red quantum dot preform lattice, and removing the mask. The area of the bottom surface of the red quantum dot preform close to the n-type gallium nitride layer 3 is 100 - 150 nm 2 .

[0072] Step S22, as shown in Figure 5 and Figure 6 , forming a green quantum dot layer on the sides of the n-type gallium nitride layer 3 and the red quantum dot preform away from the substrate 1, patterning the green quantum dot layer using inductively coupled plasma etching technology to obtain a green quantum dot preform lattice.

[0073] Exemplarily, in step S22, using the MBE process, using high-purity Ga source and P source materials, precisely controlling the beam currents of Ga and P to grow a green quantum dot layer with a thickness of 8 - 10 nm; then growing a SiO2 mask for dry etching on the green quantum dot layer, patterning the mask using photolithography, and etching to form a green quantum dot preform using ICP etching technology. The area of the bottom surface of the green quantum dot preform close to the n-type gallium nitride layer 3 is 65 - 100 nm 2 .

[0074] Step S23, as shown in Figure 7 and Figure 8 , forming a blue quantum dot layer on the sides of the n-type gallium nitride layer 3, the red quantum dot preform, and the green quantum dot preform away from the substrate 1, patterning the blue quantum dot layer using inductively coupled plasma etching technology to obtain a blue quantum dot preform lattice.

[0075] Exemplarily, in step S23, using the MBE process, using high-purity Ga source, In source, and N source materials, precisely controlling the beam currents of Ga, In, and N to achieve the required In x Ga 1-xAn N-component (where x = 0.2), a blue quantum dot layer with a growth thickness of 8 - 10 nm; then a SiO2 mask for dry etching is grown on the blue quantum dot layer, the mask is patterned by photolithography, and an ICP etching technique is used to etch and form a blue quantum dot preform. The area of the bottom surface of the blue quantum dot preform close to one side of the n-type gallium nitride layer 3 is 35 - 65 nm 2 .

[0076] In this embodiment, the preparation sequence of the quantum dot preforms is the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform in turn. It should be noted that in other embodiments, other preparation sequences can also be used for the preparation of the quantum dot preforms. For example, the preparation can be carried out in the order of the green quantum dot preform, the blue quantum dot preform, and the red quantum dot preform.

[0077] In one example, in step S20, the bottom surfaces of the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform close to one side of the n-type gallium nitride layer 3 are any one of a square, a rectangle, or a circle. It can be understood that the bottom surface shapes of the quantum dot preforms of the three colors close to one side of the n-type gallium nitride layer 3 can be the same or different. In step S30, the red quantum dot pyramid, the green quantum dot pyramid, and the blue quantum dot pyramid are a pyramid or a cone. That is to say, when the bottom surface shapes of the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform close to one side of the n-type gallium nitride layer 3 are a square or a rectangle, the red quantum dot pyramid, the green quantum dot pyramid, and the blue quantum dot pyramid obtained after photolithography are pyramids; when the bottom surface shapes of the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform close to one side of the n-type gallium nitride layer 3 are a circle, the red quantum dot pyramid, the green quantum dot pyramid, and the blue quantum dot pyramid obtained after photolithography are cones.

[0078] In one embodiment of the present invention, as Figure 10 shown (taking the bottom surface shapes of the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform close to one side of the n-type gallium nitride layer 3 as squares as an example), it is an arrangement mode of the quantum dot array. Along the first direction D1, it includes a plurality of repeating quantum dot units, and the quantum dot units are arranged in the order of blue quantum dot BQD, green quantum dot GQD, blue quantum dot BQD, and red quantum dot RQD in the first direction D1. Along the second direction D2, it includes a plurality of repeating quantum dot units, and the quantum dot units are arranged in the order of blue quantum dot BQD, green quantum dot GQD, blue quantum dot BQD, and red quantum dot RQD in the second direction D2.

[0079] In another embodiment of the present invention, as Figure 11As shown (taking the shape of the bottom surface of the red quantum dot preform, the green quantum dot preform, and the blue quantum dot preform close to one side of the n-type gallium nitride layer 3 as a square), this is another arrangement mode of the quantum dot array. The quantum dot array includes three quantum dot rings, namely a green quantum dot ring, a red quantum dot ring surrounding the green quantum dot ring, and a blue quantum dot ring surrounding the red quantum dot ring. The design of this quantum dot arrangement is simple. By arranging the quantum dots of the three primary colors in a ring shape, the light mixing effect is improved. In this embodiment, white light can be obtained by light mixing by adjusting the spacing between quantum dots of the same primary color, the spacing between quantum dots of different primary colors, and the arrangement density of the quantum dots.

[0080] The present invention also provides a display device, which can be a mobile phone, a tablet, a vehicle-mounted display, etc. The display device includes a display module and a backlight module, and the backlight module includes the above-mentioned quantum dot white LED.

[0081] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A quantum dot white light LED, characterized in that, It includes a substrate, a gallium nitride buffer layer, an n-type gallium nitride layer, a quantum dot layer, and a p-type gallium nitride layer that are sequentially stacked on one side of the substrate; and a first electrode electrically connected to the n-type gallium nitride layer and a second electrode electrically connected to the p-type gallium nitride layer; The quantum dot layer includes a quantum dot lattice composed of a plurality of quantum dot cones, and the bottom surface of the quantum dot cone is closer to the n-type gallium nitride layer than the vertex of the quantum dot cone; The quantum dot cones include red quantum dot cones, blue quantum dot cones, and green quantum dot cones; The blue quantum dot cone is In x Ga 1-x N, the red quantum dot cone is Al y Ga z In 1-y-z P, and the green quantum dot cone is GaP, where x is from 0.1 to 0.25, y is from 0.15 to 0.3, and z is from 0.15 to 0.

3.

2. The quantum dot white light LED according to claim 1, wherein, Among the total number of quantum dot cones in the quantum dot layer, the blue light quantum dot cones account for 40-60% of the total, the green light quantum dot cones account for 30-40% of the total, and the red light quantum dot cones account for 30-40% of the total.

3. The quantum dot white light LED according to claim 1 or 2, characterized in that, The orthographic projection area of the blue quantum dot cone on the substrate is 35 to 65 nm 2 , the orthographic projection area of the red quantum dot cone on the substrate is 100 to 150 nm 2 , the orthographic projection area of the green quantum dot cone on the substrate is 65 to 100 nm 2 .

4. The quantum dot white light LED according to claim 3, wherein, The thickness of the quantum dot layer is 8-10 nm.

5. The quantum dot white light LED according to claim 4, wherein The substrate is a gallium oxide substrate or a C-plane sapphire substrate.

6. The preparation method of the quantum dot white light LED according to claim 1, characterized in that, It includes the following steps: S10. Obtain a substrate, and sequentially form a gallium nitride buffer layer and an n-type gallium nitride layer on one side of the substrate; S20. Form a red quantum dot preform lattice, a green quantum dot preform lattice, and a blue quantum dot preform lattice on the side of the n-type gallium nitride layer away from the substrate; wherein, the blue quantum dot preform is In x Ga 1-x N, the red quantum dot preform is Al y Ga z In 1-y-z P, the green quantum dot preform is GaP, x is 0.1 to 0.25, y is 0.15 to 0.3, and z is 0.15 to 0.3; S30. Use a photolithography process to etch each red quantum dot preform, green quantum dot preform, and blue quantum dot preform to form red quantum dot cones, green quantum dot cones, and blue quantum dot cones, and obtain a quantum dot layer; S40. Form a p-type gallium nitride layer on the side of the quantum dot layer away from the substrate, form a first electrode on the side of the n-type gallium nitride layer away from the substrate, and form a second electrode on the side of the p-type gallium nitride layer away from the substrate to obtain a quantum dot white light LED.

7. The preparation method of the quantum dot white light LED according to claim 6, characterized in that, In step S20, forming a red quantum dot preform lattice, a green quantum dot preform lattice, and a blue quantum dot preform lattice on the side of the n-type gallium nitride layer away from the substrate includes: Form a red quantum dot layer on the side of the n-type gallium nitride layer away from the substrate, and use inductively coupled plasma etching technology to pattern the red quantum dot layer to obtain a red quantum dot preform lattice; Form a green quantum dot layer on the side of the n-type gallium nitride layer and the red quantum dot preform away from the substrate, and use inductively coupled plasma etching technology to pattern the green quantum dot layer to obtain a green quantum dot preform lattice; Form a blue quantum dot layer on the side of the n-type gallium nitride layer, the red quantum dot preform, and the green quantum dot preform away from the substrate, and use inductively coupled plasma etching technology to pattern the blue quantum dot layer to obtain a blue quantum dot preform lattice.

8. The preparation method of the quantum dot white light LED according to claim 7, wherein, In steps S20 and S30, the bottom area of the red quantum dot preform on the side close to the n-type gallium nitride layer is equal to the bottom area of the red quantum dot cone on the side close to the n-type gallium nitride layer; The bottom area of the green quantum dot preform on the side close to the n-type gallium nitride layer is equal to the bottom area of the green quantum dot cone on the side close to the n-type gallium nitride layer; The bottom area of the blue quantum dot preform on the side close to the n-type gallium nitride layer is equal to the bottom area of the blue quantum dot cone on the side close to the n-type gallium nitride layer.

9. The preparation method of the quantum dot white light LED according to any one of claims 6-8, characterized in that, The bottom surface of the red quantum dot preform, green quantum dot preform, and blue quantum dot preform on the side close to the n-type gallium nitride layer in step S20 is any one of a square, a rectangle, or a circle; In step S30, the red quantum dot cone, the green quantum dot cone, and the blue quantum dot cone are pyramids or cones.

10. A display device, characterized in that, It includes a display module and a backlight module, and the backlight module includes the quantum dot white LED according to any one of claims 1-5.

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