Light emitting diode and preparation method thereof

Abstract

The invention provides a light emitting diode and a preparation method thereof, and belongs to the technical field of photoelectron manufacturing. The light-emitting diode comprises a buffer layer, a filling layer, a first semiconductor layer, a light-emitting layer, an electron blocking layer and a second semiconductor layer which are stacked in sequence, the electron blocking layer comprises a first electron blocking sub-layer and a second electron blocking sub-layer, and the second semiconductor layer comprises a low-temperature semiconductor sub-layer and a high-temperature semiconductor sub-layer. The first electron blocking sub-layer, the low-temperature semiconductor sub-layer, the second electron blocking sub-layer and the high-temperature semiconductor sub-layer are sequentially stacked on the light-emitting layer; the first electron blocking sub-layer is an AlN / GaN / AlGaN laminated layer, the low-temperature semiconductor sub-layer is a GaN / AlGaN / InGaN laminated layer, and the second electron blocking sub-layer is an AlGaN layer.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic manufacturing technologies, and particularly to a light emitting diode and a method for preparing the same. Background Art

[0002] As a highly influential new product in the optoelectronic industry, a light emitting diode (LED) has the characteristics of small size, long service life, rich and colorful colors, low energy consumption, etc., and is widely used in fields such as lighting, display screens, signal lights, backlights, toys, etc.

[0003] In related technologies, a light emitting diode generally includes a buffer layer, a planarization layer, a first semiconductor layer, a light emitting layer, an electron blocking layer, and a second semiconductor layer that are stacked in sequence.

[0004] Although the electron blocking layer can block electrons, it also has a great influence on the holes injected from the second semiconductor layer into the light emitting layer, thereby affecting photon recombination radiation and the light emitting efficiency. Summary of the Invention

[0005] Embodiments of the present disclosure provide a light emitting diode and a method for preparing the same, which can improve the blocking of holes by the electron blocking layer and improve the light emitting efficiency of the light emitting diode. The technical solutions are as follows:

[0006] On the one hand, a light emitting diode is provided, and the light emitting diode includes:

[0007] A buffer layer, a planarization layer, a first semiconductor layer, a light emitting layer, an electron blocking layer, and a second semiconductor layer that are stacked in sequence;

[0008] The electron blocking layer includes a first electron blocking sub-layer and a second electron blocking sub-layer, the second semiconductor layer includes a low-temperature semiconductor sub-layer and a high-temperature semiconductor sub-layer, and the first electron blocking sub-layer, the low-temperature semiconductor sub-layer, the second electron blocking sub-layer, and the high-temperature semiconductor sub-layer are stacked on the light emitting layer in sequence;

[0009] The first electron blocking sub-layer is an AlN / GaN / AlGaN stack, the low-temperature semiconductor sub-layer is a GaN / AlGaN / InGaN stack, and the second electron blocking sub-layer is an AlGaN layer.

[0010] Optionally, the thicknesses of the AlN, GaN, and AlGaN layers in the first electron blocking sub-layer are 2-4 nm, 1-3 nm, and 2-3 nm respectively.

[0011] Optionally, the Al components in the AlN and AlGaN layers in the first electron blocking sub-layer are 10-15% and 5-10% respectively.

[0012] Optionally, the thicknesses of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor sublayer are 5-10 nm, 10-20 nm, and 15-30 nm, respectively.

[0013] Optionally, the Al component in the AlGaN layer in the low-temperature semiconductor sublayer is 5-10%.

[0014] Optionally, the second electron blocking sublayer is an Al y Ga 1-y N layer, where 0.05 < y < 0.3.

[0015] Optionally, the thickness of the second electron blocking sublayer is 5-10 nm.

[0016] On the other hand, a method for manufacturing a light-emitting diode is provided, and the manufacturing method includes:

[0017] Fabricating a buffer layer;

[0018] Fabricating a planarizing layer on the buffer layer;

[0019] Successively fabricating a first semiconductor layer, a light-emitting layer, an electron blocking layer, and a second semiconductor layer on the planarizing layer;

[0020] The electron blocking layer includes a first electron blocking sublayer and a second electron blocking sublayer, the second semiconductor layer includes a low-temperature semiconductor sublayer and a high-temperature semiconductor sublayer, and the first electron blocking sublayer, the low-temperature semiconductor sublayer, the second electron blocking sublayer, and the high-temperature semiconductor sublayer are successively stacked on the light-emitting layer;

[0021] The first electron blocking sublayer is an AlN / GaN / AlGaN stack, the low-temperature semiconductor sublayer is a GaN / AlGaN / InGaN stack, and the second electron blocking sublayer is an AlGaN layer.

[0022] Optionally, the growth temperature of the AlN / GaN / AlGaN stack in the first electron blocking sublayer is 800-900 °C.

[0023] Optionally, the growth temperatures of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor sublayer are 700-750 °C, 750-800 °C, and 800-850 °C, respectively.

[0024] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure at least include:

[0025] In the light-emitting diode provided by the embodiment of the present disclosure, an AlN / GaN / AlGaN stack is arranged behind the light-emitting layer. The AlN / GaN / AlGaN stack includes an AlN layer with a high energy level, forming a first-wave electron blocking barrier to filter and block a part of electrons. Then, the low-temperature semiconductor sub-layer is a GaN / AlGaN / InGaN stack, on the one hand, to provide holes as much as possible, and on the other hand, to prevent the second-wave electrons from leaking into the high-temperature semiconductor sub-layer. Through the second electron blocking sub-layer, due to the existence of the first electron blocking sub-layer, the Al component in the second electron blocking sub-layer can be reduced more compared with a single electron blocking layer. Therefore, although the second electron blocking sub-layer is closer to the high-temperature semiconductor sub-layer, due to the two previous electron blockings, the second electron blocking sub-layer will not affect the electron blocking effect even when the Al is significantly reduced. At the same time, due to the lower potential barrier, holes can move in large quantities towards the quantum well direction, forming a continuous hole current. Since electrons are blocked three times, the non-radiative recombination is greatly reduced. Since it helps to form a stable flow of hole current, the radiative recombination is greatly enhanced, and finally the luminous efficiency of the light-emitting diode is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0028] Figure 2 is a schematic structural diagram of another light-emitting diode provided by an embodiment of the present disclosure;

[0029] Figure 3 is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure;

[0030] Figure 4 is a flowchart of another method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure.

[0031] The reference numerals are as follows:

[0032] 100: substrate; 101: buffer layer; 102: planarizing layer; 103: first semiconductor layer; 104: light-emitting layer; 105: electron blocking layer; 106: second semiconductor layer; 151: first electron blocking sub-layer; 152 second electron blocking sub-layer; 161: low-temperature semiconductor sub-layer; 162: high-temperature semiconductor sub-layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To make the objectives, technical solutions, and advantages of the present disclosure clearer, the following will further describe the embodiments of the present disclosure in detail with reference to the accompanying drawings.

[0034] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", "third", and similar terms used in the specification and claims of the present patent application do not denote any order, quantity, or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a quantity limitation, but mean that there is at least one. The terms "comprising" or "including" and similar terms mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, without excluding other elements or items. The terms "connected" or "coupled" and similar terms are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", "top", "bottom", etc. are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationships may also change accordingly.

[0035] Figure 1 is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure. Refer to Figure 1 , the light-emitting diode includes:

[0036] a buffer layer 101, a planarization layer 102, a first semiconductor layer 103, a light-emitting layer 104, an electron blocking layer 105, and a second semiconductor layer 106 stacked in sequence;

[0037] The electron blocking layer 105 includes a first electron blocking sublayer 151 and a second electron blocking sublayer 152, the second semiconductor layer 106 includes a low-temperature semiconductor sublayer 161 and a high-temperature semiconductor sublayer 162, and the first electron blocking sublayer 151, the low-temperature semiconductor sublayer 161, the second electron blocking sublayer 152, and the high-temperature semiconductor sublayer 162 are stacked in sequence on the light-emitting layer 104;

[0038] The first electron blocking sublayer 151 is an AlN / GaN / AlGaN stack, the low-temperature semiconductor sublayer 161 is a GaN / AlGaN / InGaN stack, and the second electron blocking sublayer 152 is an AlGaN layer.

[0039] In the light-emitting diode provided by the embodiment of the present disclosure, an AlN / GaN / AlGaN stack is arranged behind the light-emitting layer. The AlN / GaN / AlGaN stack includes an AlN layer with a high energy level, forming a first-wave electron blocking barrier to filter and block part of the electrons. Then, the low-temperature semiconductor sublayer is a GaN / AlGaN / InGaN stack, which on the one hand is to provide holes as much as possible, and on the other hand is also to prevent the leakage of the second-wave electrons into the high-temperature semiconductor sublayer. Then, through the second electron blocking sublayer, due to the existence of the first electron blocking sublayer, the Al component in the second electron blocking sublayer can be reduced more compared with a single electron blocking layer. Therefore, although the second electron blocking sublayer is closer to the high-temperature semiconductor sublayer, due to the two previous electron blockings, the second electron blocking sublayer will not affect the electron blocking effect even when the Al is significantly reduced. At the same time, due to the lower barrier, holes can move in large quantities towards the quantum well direction, forming a continuous hole current. Since the electrons are triple-blocked, the non-radiative recombination is greatly reduced. Since it helps to form a stable flow of hole current, the radiative recombination is greatly enhanced, and finally the luminous efficiency of the light-emitting diode is improved.

[0040] In the embodiment of the present disclosure, the buffer layer 101 may include a stacked two-dimensional buffer layer and a three-dimensional nucleation layer.

[0041] In the embodiment of the present disclosure, the first semiconductor layer 103 is an Si-doped layer, and the high-temperature semiconductor sublayer 162 is an Mg-doped layer.

[0042] Exemplarily, the first semiconductor layer 103 is an Si-doped GaN layer, and the high-temperature semiconductor sublayer 162 is an Mg-doped GaN layer.

[0043] Figure 2 It is a schematic structural diagram of another light-emitting diode provided by the embodiment of the present disclosure. Refer to Figure 2 , the light-emitting diode further includes: a substrate 100, and a buffer layer 101 is located on the substrate 100.

[0044] In the embodiment of the present disclosure, the substrate 100 may be a sapphire substrate.

[0045] In the embodiment of the present disclosure, both the buffer layer 101 and the planarization layer 102 are GaN layers.

[0046] In the embodiment of the present disclosure, the light-emitting layer 104 may be a multi-quantum well barrier layer.

[0047] Exemplarily, the light-emitting layer 104 is a superlattice composed of 8 to 15 periods of In x Ga 1-x N(0.2 < x < 0.5) quantum wells / GaN (or AlGaN) quantum barriers.

[0048] In the embodiments of the present disclosure, the thicknesses of the AlN, GaN, and AlGaN layers in the first electron blocking layer 151 are 2-4 nm, 1-3 nm, and 2-3 nm, respectively.

[0049] Exemplarily, the thicknesses of the AlN, GaN, and AlGaN layers in the first electron blocking layer 151 are 3 nm, 2 nm, and 2.5 nm, respectively.

[0050] In the embodiments of the present disclosure, the Al components in the AlN and AlGaN layers in the first electron blocking layer 151 are 10-15% and 5-10%, respectively.

[0051] Exemplarily, the Al components in the AlN and AlGaN layers in the first electron blocking layer 151 are 12.5% and 7.5%, respectively.

[0052] In the first electron blocking layer 151, the Al component shows a trend of being higher at the front and lower at the back, which can more effectively block electrons and is beneficial to the forward injection of holes.

[0053] In the embodiments of the present disclosure, the growth temperature of the AlN / GaN / AlGaN stack in the first electron blocking layer is 800-900 °C.

[0054] Exemplarily, the growth temperature of the AlN / GaN / AlGaN stack in the first electron blocking layer is 850 °C.

[0055] In the embodiments of the present disclosure, the thicknesses of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor layer 161 are 5-10 nm, 10-20 nm, and 15-30 nm, respectively.

[0056] Exemplarily, the thicknesses of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor layer 161 are 7.5 nm, 15 nm, and 22.5 nm, respectively.

[0057] In the low-temperature semiconductor layer 161, the thicknesses of the respective sub-layers show a trend of being thinner at the front and thicker at the back. The AlGaN and InGaN are relatively thick because the Al / In doping is an impurity, which is not conducive to crystal growth. Growing thicker is more conducive to the entry of Al / In doping, thereby achieving the growth purpose of the low-temperature semiconductor layer.

[0058] In the embodiments of the present disclosure, the Al component in the AlGaN layer in the low-temperature semiconductor layer 161 is 5-10%.

[0059] Exemplarily, the Al component in the AlGaN layer in the low-temperature semiconductor layer 161 is 7.5%.

[0060] In the embodiments of the present disclosure, the growth temperatures of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor sublayer are 700-750 °C, 750-800 °C, and 800-850 °C, respectively.

[0061] Exemplarily, the growth temperatures of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor sublayer are 725 °C, 775 °C, and 825 °C, respectively.

[0062] In the embodiments of the present disclosure, the second electron blocking sublayer 152 is an Al y Ga 1-y N layer, where 0.05 < y < 0.3.

[0063] In this implementation, the Al component value is 0.05 < y < 0.3, which is much smaller than the value in the related art for a single electron blocking layer (0.2 < y < 0.5), and the Al component is significantly reduced.

[0064] Exemplarily, the value of y is 0.05 or 0.06.

[0065] In the embodiments of the present disclosure, the thickness of the second electron blocking sublayer 152 is 5-10 nm.

[0066] Exemplarily, the thickness of the second electron blocking sublayer 152 is 8 nm.

[0067] In the embodiments of the present disclosure, the thickness of the high-temperature semiconductor sublayer 162 is 3-5 nm.

[0068] Exemplarily, the thickness of the high-temperature semiconductor sublayer 162 is 4 nm.

[0069] It should be noted that in the embodiments of the present disclosure, the structure of the above light-emitting diode can be selectively increased or decreased, and the present disclosure does not limit this.

[0070] Figure 3 is a flowchart of a method for manufacturing a light-emitting diode provided by the embodiments of the present disclosure. As Figure 3 shown, the manufacturing method includes:

[0071] Step 301: Fabricate a buffer layer.

[0072] Step 302: Fabricate a planarizing layer on the buffer layer.

[0073] Step 303: Sequentially fabricate a first semiconductor layer, a light-emitting layer, an electron blocking layer, and a second semiconductor layer on the planarizing layer.

[0074] Wherein, the electron blocking layer includes a first electron blocking sub-layer and a second electron blocking sub-layer, the second semiconductor layer includes a low-temperature semiconductor sub-layer and a high-temperature semiconductor sub-layer, and the first electron blocking sub-layer, the low-temperature semiconductor sub-layer, the second electron blocking sub-layer, and the high-temperature semiconductor sub-layer are sequentially stacked on the light-emitting layer;

[0075] The first electron blocking sub-layer is an AlN / GaN / AlGaN stack, the low-temperature semiconductor sub-layer is a GaN / AlGaN / InGaN stack, and the second electron blocking sub-layer is an AlGaN layer.

[0076] In the light-emitting diode provided by the embodiment of the present disclosure, an AlN / GaN / AlGaN stack is arranged behind the light-emitting layer. The AlN / GaN / AlGaN stack includes a high-energy-level AlN layer, forming a first-wave electron blocking potential barrier to filter and block a part of electrons; then the low-temperature semiconductor sub-layer is a GaN / AlGaN / InGaN stack, on the one hand, to provide holes as much as possible, and on the other hand, to prevent the second-wave electrons from leaking into the high-temperature semiconductor sub-layer; then through the second electron blocking sub-layer, due to the existence of the first electron blocking sub-layer, the Al component in the second electron blocking sub-layer can be reduced more compared with a single electron blocking layer. Therefore, although the second electron blocking sub-layer is closer to the high-temperature semiconductor sub-layer, due to the two previous electron blockings, the second electron blocking sub-layer will not affect the electron blocking effect even when the Al is significantly reduced. At the same time, due to the lower potential barrier, holes can move in large quantities towards the quantum well direction, forming a continuous hole current. Since the electrons are triple-blocked, the non-radiative recombination is greatly reduced. Since it helps to form a stable flow of hole current, the radiative recombination is greatly enhanced, and finally the luminous efficiency of the light-emitting diode is improved.

[0077] In the embodiment of the present disclosure, the buffer layer, the planarizing layer, the first semiconductor layer, the light-emitting layer, and the second semiconductor layer are grown in a reaction chamber. The reaction chamber is a reaction chamber of an MOCVD (Metal Organic Chemical Vapor Deposition) device.

[0078] Wherein, when growing each film layer, the growth substrate is placed in a graphite disk in the MOCVD reaction chamber. By introducing MO sources and reaction gases into the reaction chamber and controlling the rotation of the graphite disk, each film layer is formed on the substrate in the graphite disk.

[0079] Figure 4 It is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure. As Figure 4 shown, the manufacturing method includes:

[0080] Step 401: Grow a buffer layer on the substrate.

[0081] In an embodiment of the present disclosure, the substrate 100 may be a sapphire substrate.

[0082] In an embodiment of the present disclosure, the buffer layer 101 may include a stacked two-dimensional buffer layer and a three-dimensional nucleation layer.

[0083] Step 402: Fabricate a planarization layer on the buffer layer.

[0084] In an embodiment of the present disclosure, both the buffer layer 101 and the planarization layer 102 are GaN layers.

[0085] Step 403: Sequentially grow a first semiconductor layer and a light-emitting layer on the planarization layer.

[0086] In an embodiment of the present disclosure, the first semiconductor layer 103 is an Si-doped layer.

[0087] Exemplarily, the first semiconductor layer 103 is an Si-doped GaN layer.

[0088] In an embodiment of the present disclosure, the light-emitting layer 104 may be a multi-quantum well barrier layer.

[0089] Exemplarily, the light-emitting layer 104 is a superlattice composed of 8 to 15 periods of In x Ga 1-x N (0.2 < x < 0.5) quantum wells / GaN (or AlGaN) quantum barriers.

[0090] Step 404: Sequentially grow a first electron blocking layer, a low-temperature semiconductor layer, a second electron blocking layer, and a high-temperature semiconductor layer on the light-emitting layer.

[0091] In an embodiment of the present disclosure, the high-temperature semiconductor layer 162 is an Mg-doped layer.

[0092] Exemplarily, the high-temperature semiconductor layer 162 is an Mg-doped GaN layer.

[0093] In an embodiment of the present disclosure, the thicknesses of the AlN, GaN, and AlGaN layers in the first electron blocking layer 151 are 2 to 4 nm, 1 to 3 nm, and 2 to 3 nm, respectively.

[0094] Exemplarily, the thicknesses of the AlN, GaN, and AlGaN layers in the first electron blocking layer 151 are 3 nm, 2 nm, and 2.5 nm, respectively.

[0095] In an embodiment of the present disclosure, the Al components in the AlN and AlGaN layers in the first electron blocking layer 151 are 10 to 15% and 5 to 10%, respectively.

[0096] Exemplarily, the Al components in the AlN and AlGaN layers of the first electron blocking layer 151 are 12.5% and 7.5% respectively.

[0097] In the first electron blocking layer 151, the Al component shows a trend of being high in the front and low in the back, which can more effectively block electrons and at the same time is beneficial to the forward injection of holes.

[0098] In the embodiment of the present disclosure, the growth temperature of the AlN / GaN / AlGaN stack in the first electron blocking layer is 800 - 900 °C.

[0099] Exemplarily, the growth temperature of the AlN / GaN / AlGaN stack in the first electron blocking layer is 850 °C.

[0100] In the embodiment of the present disclosure, the thicknesses of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor layer 161 are 5 - 10 nm, 10 - 20 nm, and 15 - 30 nm respectively.

[0101] Exemplarily, the thicknesses of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor layer 161 are 7.5 nm, 15 nm, and 22.5 nm respectively.

[0102] In the low-temperature semiconductor layer 161, the thicknesses of the respective sub-layers show a trend of being thin in the front and thick in the back. The relatively thick AlGaN and InGaN are because Al / In doping is an impurity, which is not conducive to crystal growth. Making them thicker is more conducive to the entry of Al / In doping, thereby achieving the growth purpose of the low-temperature semiconductor layer.

[0103] In the embodiment of the present disclosure, the Al component in the AlGaN layer of the low-temperature semiconductor layer 161 is 5 - 10%.

[0104] Exemplarily, the Al component in the AlGaN layer of the low-temperature semiconductor layer 161 is 7.5%.

[0105] In the embodiment of the present disclosure, the growth temperatures of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor layer are 700 - 750 °C, 750 - 800 °C, and 800 - 850 °C respectively.

[0106] Exemplarily, the growth temperatures of the GaN, AlGaN, and InGaN layers in the low-temperature semiconductor layer are 725 °C, 775 °C, and 825 °C respectively.

[0107] In this implementation, the low-temperature semiconductor layer as a whole uses a relatively low temperature and shows a trend of gradually increasing temperature. On the one hand, it can form a certain coarsening effect, which is beneficial to light emission. On the other hand, it is beneficial to the incorporation of In.

[0108] In the embodiment of the present disclosure, the second electron blocking sublayer 152 is an Al y Ga 1-y N layer, where 0.05 < y < 0.3.

[0109] In this implementation, the value of the Al component is 0.05 < y < 0.3, which is much smaller than the value (0.2 < y < 0.5) in the related art for a single electron blocking layer, and the Al component is significantly reduced.

[0110] Exemplarily, the value of y is 0.05 or 0.06.

[0111] In the embodiment of the present disclosure, the thickness of the second electron blocking sublayer 152 is 5 - 10 nm.

[0112] Exemplarily, the thickness of the second electron blocking sublayer 152 is 8 nm.

[0113] In the embodiment of the present disclosure, the growth temperature of the second electron blocking sublayer 152 is 800 - 900 °C, and the growth pressure is 50 - 250 torr.

[0114] Exemplarily, the growth temperature of the second electron blocking sublayer 152 is 850 °C, and the growth pressure is 150 torr.

[0115] In the embodiment of the present disclosure, the thickness of the high-temperature semiconductor sublayer 162 is 3 - 5 nm.

[0116] Exemplarily, the thickness of the high-temperature semiconductor sublayer 162 is 4 nm.

[0117] In the embodiment of the present disclosure, the growth temperature of the high-temperature semiconductor sublayer 162 is 850 - 1000 °C, and the growth pressure is 50 - 250 torr.

[0118] Exemplarily, the growth temperature of the high-temperature semiconductor sublayer 162 is 950 °C, and the growth pressure is 150 torr.

[0119] In the light-emitting diode provided by the embodiments of the present disclosure, an AlN / GaN / AlGaN stack is arranged behind the light-emitting layer. The AlN / GaN / AlGaN stack includes an AlN layer with a high energy level, forming a first-wave electron blocking barrier to filter and block a part of electrons. Then, the low-temperature semiconductor sub-layer is a GaN / AlGaN / InGaN stack, which is for providing holes as much as possible on the one hand and also for the purpose of blocking the leakage of the second-wave electrons into the high-temperature semiconductor sub-layer on the other hand. Through the second electron blocking sub-layer, due to the existence of the first electron blocking sub-layer, the Al component in the second electron blocking sub-layer can be reduced more compared with a single electron blocking layer. Therefore, although the second electron blocking sub-layer is closer to the high-temperature semiconductor sub-layer, since electron blocking has been carried out twice before, the second electron blocking sub-layer will not affect the electron blocking effect even when the Al content is significantly reduced. At the same time, due to the lower barrier, holes can move towards the quantum well in large quantities, forming a continuous hole current. Since electrons are blocked three times, the non-radiative recombination is greatly reduced. Since it helps to form a stable flow of hole current, the radiative recombination is greatly enhanced, and finally the light-emitting efficiency of the light-emitting diode is improved.

[0120] The above are only optional embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A light emitting diode, characterized in that: The light emitting diode comprises: A buffer layer (101), a fill layer (102), a first semiconductor layer (103), a light-emitting layer (104), an electron blocking layer (105), and a second semiconductor layer (106) stacked in sequence; The electron blocking layer (105) comprises a first electron blocking sublayer (151) and a second electron blocking sublayer (152); the second semiconductor layer (106) comprises a low-temperature semiconductor sublayer (161) and a high-temperature semiconductor sublayer (162); the first electron blocking sublayer (151), the low-temperature semiconductor sublayer (161), the second electron blocking sublayer (152) and the high-temperature semiconductor sublayer (162) are sequentially stacked on the light-emitting layer (104); The first electron blocking sublayer (151) is an AlN / GaN / AlGaN stacked layer, the low-temperature semiconductor sublayer (161) is a GaN / AlGaN / InGaN stacked layer, and the second electron blocking sublayer (152) is an AlGaN layer.

2. The light emitting diode according to claim 1, characterized in that: The thicknesses of the AlN, GaN and AlGaN layers in the first electron blocking sublayer (151) are 2-4 nm, 1-3 nm and 2-3 nm respectively.

3. The light emitting diode according to claim 2, characterized in that: The Al content in the AlN and AlGaN layers in the first electron blocking sublayer (151) is 10-15% and 5-10% respectively.

4. The light emitting diode according to any one of claims 1 to 3, characterized in that: The thicknesses of the GaN, AlGaN and InGaN layers in the low-temperature semiconductor sublayer (161) are 5-10 nm, 10-20 nm and 15-30 nm respectively.

5. The light emitting diode according to claim 4, characterized in that: The Al content in the AlGaN layer of the low-temperature semiconductor sublayer (161) is 5-10%.

6. The light emitting diode according to any one of claims 1 to 3, characterized in that: The second electron blocking sublayer (152) is Al y Ga 1-y N layers, 0.05 <y<0.3。 7. The light emitting diode according to claim 6, characterized in that: The thickness of the second electron blocking sublayer (152) is 5-10 nm.

8. A method for preparing a light emitting diode, characterized in that: The preparation method comprises: Making a buffer layer; Making a filling layer on the buffer layer; Sequentially forming a first semiconductor layer, a light-emitting layer, an electron blocking layer, and a second semiconductor layer on the filling layer; The electron blocking layer includes a first electron blocking sublayer and a second electron blocking sublayer, the second semiconductor layer includes a low-temperature semiconductor sublayer and a high-temperature semiconductor sublayer, and the first electron blocking sublayer, the low-temperature semiconductor sublayer, the second electron blocking sublayer and the high-temperature semiconductor sublayer are sequentially stacked on the light-emitting layer; The first electron blocking sublayer is an AlN / GaN / AlGaN stack, the low-temperature semiconductor sublayer is a GaN / AlGaN / InGaN stack, and the second electron blocking sublayer is an AlGaN layer.

9. The method according to claim 8, characterized in that The growth temperature of the AlN / GaN / AlGaN stack in the first electron blocking sublayer is 800-900°C.

10. The method according to claim 8, characterized in that The growth temperatures of the GaN, AlGaN and InGaN layers in the low-temperature semiconductor sublayer are 700-750° C., 750-800° C. and 800-850° C. respectively.

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