AC-driven LED device and preparation method thereof

Abstract

The invention relates to an AC-driven LED device and a preparation method thereof. The AC-driven LED device includes: a substrate layer; the first semiconductor layer is located on the surface of the substrate layer and comprises a plane part and a protruding part, and the protruding part is located on the surface of the side, opposite to the substrate layer, of the plane part; the active layer is positioned on the surface of one side, back to the substrate layer, of the convex part of the first semiconductor layer; the second semiconductor layer is located on the surface of the side, opposite to the first semiconductor layer, of the active layer, and the conduction type of the second semiconductor layer is opposite to that of the first semiconductor layer; the convex part of the first semiconductor layer, the active layer and the second semiconductor layer form an epitaxial layer of the LED device; the passivation layer is located on the surface of the side, opposite to the active layer, of the second semiconductor layer and wraps the side portion of the epitaxial layer; and the side electrode is positioned on the surface of the passivation layer opposite to the side part of the epitaxial layer. According to the alternating current driven LED device, the turn-on voltage of the device under alternating current driving can be effectively reduced, meanwhile, the injection current is increased, and the luminance of the device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of AC-driven LED devices, and in particular to an AC-driven LED device and a preparation method thereof. Background Art

[0002] Traditional light-emitting diodes (LEDs) work under direct current, which has its own limitations: as the pixel size decreases, it is difficult to integrate metal electrodes on LED devices. Therefore, many researchers have proposed alternating current (AC) driven LED devices, which are vertical structures and have insulating layers above and below for isolation. The device can emit light under AC voltage through the capacitance effect inside the device during the driving process. AC driven LEDs are feasible and have great potential in non-destructive testing and display. However, in existing AC driven LED devices, due to the presence of insulating layers at both ends of the device, a higher driving voltage needs to be applied to achieve device light emission, resulting in a higher device turn-on voltage; at the same time, due to the presence of the device insulating layer, its equivalent capacitance under AC signals causes the device injection current to be small, resulting in a low device luminous intensity and poor luminous effect. Therefore, a solution is needed to reduce the turn-on voltage of LED devices driven by AC signals, increase its injection current, increase the device luminous intensity, and thus enhance the luminous effect. Summary of the invention

[0003] Therefore, the present invention provides an AC-driven LED device and a preparation method thereof to solve the problem that the turn-on voltage of the AC-driven LED device is high and the device injection current is small under the AC signal, resulting in low device luminous intensity and poor luminous effect.

[0004] The present invention provides an AC-driven LED device, comprising: a substrate layer; a first semiconductor layer, located on the surface of the substrate layer, the first semiconductor layer comprising a planar portion and a convex portion, the convex portion being located on the surface of the planar portion facing away from the substrate layer; an active layer, located on the surface of the convex portion of the first semiconductor layer facing away from the substrate layer; a second semiconductor layer, located on the surface of the active layer facing away from the first semiconductor layer, the conductivity type of the second semiconductor layer being opposite to that of the first semiconductor layer, wherein the second semiconductor layer at the top and the substrate layer at the bottom are suitable for respectively connecting to AC electrodes; the convex portion of the first semiconductor layer, the active layer and the second semiconductor layer constitute the epitaxial layer of the LED device; a passivation layer, located on the surface of the second semiconductor layer facing away from the active layer and covering the side of the epitaxial layer; and a side electrode, located on the surface of the passivation layer facing away from the side of the epitaxial layer.

[0005] Optionally, a portion of the passivation layer located on the surface of the second semiconductor layer facing away from the active layer is provided with a first opening, and the LED device is further provided with an upper electrode, and the upper electrode is connected to the second semiconductor layer through the first opening.

[0006] Optionally, a conductive layer is further arranged between the second semiconductor layer and the passivation layer, and a second opening is provided on a portion of the passivation layer located on the surface of the conductive layer facing away from the second semiconductor layer. The LED device is also provided with an upper electrode, and the upper electrode is connected to the conductive layer through the second opening.

[0007] Optionally, the conductive layer is an ITO conductive layer, and the passivation layer is a silicon dioxide passivation layer.

[0008] Optionally, the thickness of the passivation layer is smaller than the thickness of the substrate layer.

[0009] Optionally, the side electrode fully surrounds the surface of the passivation layer facing away from the side of the epitaxial layer.

[0010] Optionally, the side electrodes cover surfaces of the passivation layer that are opposite to two side surfaces of the epitaxial layer.

[0011] Optionally, the passivation layer further covers a portion of the surface of the planar portion of the first semiconductor layer facing away from the substrate layer and not covered by the epitaxial layer.

[0012] Optionally, the side electrode further extends to and partially covers a surface of the passivation layer on a side facing away from the second semiconductor, and extends to and covers a surface of the passivation layer on a side facing away from the planar portion of the first semiconductor layer.

[0013] The present invention also provides a method for manufacturing an AC-driven LED device, comprising the following steps: providing a substrate layer; forming a first semiconductor layer, wherein the first semiconductor layer is located on the surface of the substrate layer, the first semiconductor layer includes a planar portion and a convex portion, and the convex portion is located on the surface of the planar portion facing away from the substrate layer; forming an active layer, wherein the active layer is located on the surface of the convex portion of the first semiconductor layer facing away from the substrate layer; forming a second semiconductor layer, wherein the second semiconductor layer is located on the surface of the active layer facing away from the first semiconductor layer, and the conductivity type of the second semiconductor layer is opposite to that of the first semiconductor layer; forming a passivation layer, wherein the passivation layer is located on the surface of the second semiconductor layer facing away from the active layer and covers the side of the epitaxial layer, wherein the epitaxial layer is the convex portion of the first semiconductor layer, the active layer and the second semiconductor layer; forming a side electrode, wherein the side electrode is located on the surface of the passivation layer facing away from the side of the epitaxial layer.

[0014] The technical solution of the present invention has the following advantages:

[0015] The AC-driven LED device provided by the present invention comprises a substrate layer; a first semiconductor layer, located on the surface of the substrate layer, the first semiconductor layer comprises a plane portion and a convex portion, the convex portion is located on the surface of the plane portion facing away from the substrate layer; an active layer, located on the surface of the convex portion of the first semiconductor layer facing away from the substrate layer; a second semiconductor layer, located on the surface of the active layer facing away from the first semiconductor layer, the second semiconductor layer and the first semiconductor layer have opposite conductivity types; the convex portion of the first semiconductor layer, the active layer and the second semiconductor layer constitute the epitaxial layer of the LED device; a passivation layer, located on the surface of the second semiconductor layer facing away from the active layer, and covering the side of the epitaxial layer; a side electrode, located on the surface of the passivation layer facing away from the side of the epitaxial layer. Compared with the existing AC-driven LED device, the passivation layer and the side electrode are arranged on the side of the epitaxial layer. In actual use, the second semiconductor layer at the top and the substrate layer at the bottom are usually connected to the AC electrodes respectively, the top electrode is connected to a high potential, and the bottom electrode is connected to a low potential (for example, grounded), forming a "top-bottom" path, and luminescence is achieved under AC drive. The solution of the present application adds a side electrode. When the side electrode is also connected to a low potential (for example, grounded), a "top-side" path is formed. Due to the lack of a substrate layer, the capacitance on the "top-side" path is larger than the capacitance on the "top-bottom" path, so that the capacitive reactance under high-frequency drive is smaller, which increases the current on the path, so that more carriers are injected to achieve luminescence and reduce the turn-on voltage; at the same time, the low potential of the side electrode will cause the carrier to deflect during transmission (compared to a simple vertical electric field), so that the carrier transport distance in the active layer becomes longer, and the recombination probability increases, thereby increasing the device luminescence intensity and enhancing the device luminescence effect. In addition, under the influence of high-frequency electromagnetic waves, the conductivity of the semiconductor material in the prior art will also be affected, so that the overall impedance of the device is affected. The present invention can increase the current injection, increase the device luminescence intensity, and enhance the device luminescence intensity under constant voltage working conditions by adjusting the frequency and amplitude of the electromagnetic field introduced into the device. Therefore, the AC-driven LED device provided by the present invention can effectively reduce the turn-on voltage of the LED device under AC driving, while increasing the injected current, improving the luminous intensity of the device, and thus enhancing the luminous effect of the device.

[0016] The method for preparing an AC-driven LED device provided by the present invention can prepare the AC-driven LED device provided by the present invention. The LED device will generate a certain tilt angle during the etching process, and the tilt angle naturally formed on the side of the epitaxial layer during the deposition and etching process is used to further deposit the passivation layer and the side electrode. By adding the side electrode, when the side electrode is also connected to a low potential (for example, grounded), a "top-side" path is formed. Due to the lack of a substrate layer, the capacitance on the "top-side" path is larger than the capacitance on the "top-bottom" path, so that the capacitive reactance under high-frequency driving is smaller, so that the current on the path increases, thereby causing more carriers to be injected to achieve luminescence and reduce the turn-on voltage; at the same time, the low potential of the side electrode will cause the carrier to deflect during the transmission process (compared with a simple vertical electric field), so that the carrier transport distance in the active layer becomes longer, and the recombination probability increases, thereby improving the device luminescence effect. In addition, under the influence of high-frequency electromagnetic waves, the conductivity of the semiconductor material in the prior art will also be affected, so that the overall impedance of the device is affected. The present invention can increase current injection, increase device luminous intensity, and enhance device luminous effect by adjusting the frequency and amplitude of the electromagnetic field introduced into the device under constant voltage working conditions. Therefore, the AC-driven LED device prepared by the AC-driven LED device preparation method provided by the present invention can effectively reduce the turn-on voltage of the LED device under AC drive, while increasing the injected current, increasing the device luminous intensity, and thus enhancing the device luminous effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a schematic structural diagram of an AC-driven LED device according to an embodiment of the present invention;

[0019] Figure 2 It is a structural schematic diagram of another AC-driven LED device according to an embodiment of the present invention;

[0020] Figure 3 A top view of an AC-driven LED device according to an embodiment of the present invention;

[0021] Figure 4 A top view of another AC-driven LED device according to an embodiment of the present invention;

[0022] Figure 5A schematic flow chart of a method for preparing an AC-driven LED device according to an embodiment of the present invention;

[0023] Description of reference numerals:

[0024] 100 - substrate layer; 200 - first semiconductor layer; 300 - active layer; 400 - second semiconductor layer; 500 - passivation layer; 600 - side electrode; 700 - upper electrode; 800 - conductive layer. DETAILED DESCRIPTION

[0025] In order to solve the problem that the turn-on voltage of an AC-driven LED device is high and the device injection current is small under an AC signal, resulting in low device luminous intensity and poor luminous effect, the present invention provides an AC-driven LED device, comprising: a substrate layer; a first semiconductor layer, located on the surface of the substrate layer, the first semiconductor layer comprising a plane portion and a convex portion, the convex portion being located on the surface of the plane portion facing away from the substrate layer; an active layer, located on the surface of the convex portion of the first semiconductor layer facing away from the substrate layer; a second semiconductor layer, located on the surface of the active layer facing away from the first semiconductor layer, the second semiconductor layer having a conductivity type opposite to that of the first semiconductor layer, wherein the second semiconductor layer at the top and the substrate layer at the bottom are suitable for respectively connecting to AC electrodes; the convex portion of the first semiconductor layer, the active layer and the second semiconductor layer constitute an epitaxial layer of the LED device; a passivation layer, located on the surface of the second semiconductor layer facing away from the active layer and covering the side of the epitaxial layer; and a side electrode, located on the surface of the passivation layer facing away from the side of the epitaxial layer.

[0026] The present invention also provides a method for manufacturing an AC-driven LED device, comprising the following steps: providing a substrate layer; forming a first semiconductor layer located on the surface of the substrate layer, the first semiconductor layer comprising a planar portion and a raised portion, the raised portion being located on the surface of the planar portion facing away from the substrate layer; forming an active layer located on the surface of the raised portion of the first semiconductor layer facing away from the substrate layer; forming a second semiconductor layer located on the surface of the active layer facing away from the first semiconductor layer, the conductivity type of the second semiconductor layer being opposite to that of the first semiconductor layer; forming a passivation layer located on the surface of the second semiconductor layer facing away from the active layer and covering the side of the epitaxial layer, the epitaxial layer being the raised portion of the first semiconductor layer, the active layer and the second semiconductor layer; forming a side electrode located on the surface of the passivation layer facing away from the side of the epitaxial layer.

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0028] Example 1

[0029] refer to Figure 1 , this embodiment provides an AC driven LED device, comprising:

[0030] Substrate layer 100;

[0031] A first semiconductor layer 200, located on the surface of the substrate layer 100, the first semiconductor layer 200 includes a planar portion and a convex portion, the convex portion is located on the surface of the planar portion facing away from the substrate layer 100;

[0032] The active layer 300 is located on the surface of the protruding portion of the first semiconductor layer 200 facing away from the substrate layer 100;

[0033] A second semiconductor layer 400 is located on a surface of the active layer 300 facing away from the first semiconductor layer 200, and the conductivity type of the second semiconductor layer 400 is opposite to that of the first semiconductor layer 100, wherein the second semiconductor layer on the top and the substrate layer on the bottom are suitable for connecting to AC electrodes respectively;

[0034] The raised portion of the first semiconductor layer 200, the active layer 300 and the second semiconductor layer 400 constitute an epitaxial layer of the LED device;

[0035] a passivation layer 500, located on a surface of the second semiconductor layer 400 facing away from the active layer 300, and covering a side portion of the epitaxial layer;

[0036] The side electrode 600 is located on the surface of the passivation layer 500 facing away from the side of the epitaxial layer.

[0037] In actual use, the second semiconductor layer 400 at the top and the substrate layer 100 at the bottom are usually connected to AC electrodes respectively, the top electrode is connected to a high potential, and the bottom electrode is connected to a low potential (such as grounding), forming a "top-bottom" path to achieve luminescence under AC drive.

[0038] The AC-driven LED device provided by the present invention adds side electrodes on the basis of the prior art. When the side electrodes are also connected to a low potential (for example, grounded), a "top-side" path is formed. Due to the lack of a substrate layer, the capacitance on the "top-side" path is larger than the capacitance on the "top-bottom" path, so that the capacitive reactance under high-frequency driving is smaller, so that the current on the path increases, thereby causing more carrier injection to achieve luminescence and reduce the turn-on voltage; at the same time, the low potential of the side electrode will cause the carrier to deflect during transmission (compared to a simple vertical electric field), so that the carrier transport distance in the active layer becomes longer, the recombination probability increases, and the device luminescence intensity is improved. In addition, under the influence of high-frequency electromagnetic waves in the prior art, the conductivity of the semiconductor material will also be affected, so that the overall impedance of the device is affected. The present invention can increase the current injection, increase the device luminescence intensity, and enhance the device luminescence effect under constant voltage working conditions by adjusting the frequency and amplitude of the electromagnetic field introduced into the device. Therefore, the AC-driven LED device provided by the present invention can effectively reduce the turn-on voltage of the LED device under AC driving, while increasing the injected current, improving the luminous intensity of the device, and thus enhancing the luminous effect of the device.

[0039] Further, in this embodiment, it can be as follows Figure 1 As shown, the passivation layer 500 is provided with a first opening on the surface of the second semiconductor layer 400 facing away from the active layer. The LED device is also provided with an upper electrode 700. The upper electrode 700 is connected to the second semiconductor layer 400 through the first opening.

[0040] In different embodiments, the first opening exposes the surface of the second semiconductor layer 400 facing away from the active layer 300. The first opening may be in the middle of the second semiconductor layer 400, or may be located to the left or right. The specific location is set according to actual conditions, and the present invention does not limit this. The width of the portion of the upper electrode 700 that exceeds the passivation layer 500 is greater than the width of the opening, forming a "T"-shaped structure.

[0041] Further, in this embodiment, it can be as follows Figure 2 As shown, a conductive layer 800 is further disposed between the second semiconductor layer 400 and the passivation layer 500. A second opening is disposed on a portion of the passivation layer 500 located on the surface of the conductive layer 800 facing away from the second semiconductor layer 400, and the LED device is further provided with an upper electrode, and the upper electrode 700 is connected to the conductive layer 800 through the second opening. The second opening exposes the surface of the second semiconductor layer 400 facing away from the active layer 300, and the conductive layer 800 at least covers the surface of the second semiconductor layer 400 exposed by the first opening.

[0042] A conductive layer 800 is added between the second semiconductor layer 400 and the passivation layer 500. The conductive layer 800 is generally a transparent conductive film having the advantages of high transparency, low resistance, and high corrosion resistance. It can improve current expansion and avoid current crowding under conditions of large current injection. It can also achieve ohmic contact with the second semiconductor while ensuring high light transmittance, thereby improving conductivity.

[0043] In different embodiments, the second opening may be in the middle of the conductive layer 800, or may be located to the left or right. The width of the portion of the upper electrode 700 extending beyond the passivation layer 500 is greater than the width of the opening, forming a "T"-shaped structure.

[0044] Furthermore, in some embodiments, the conductive layer is an ITO conductive layer. The conductive layer is selected as an ITO conductive layer because ITO is a metal compound with good transparent conductive properties, has a wide band gap, high light transmittance in the visible spectrum region, and low resistivity, so it can achieve the effects of light transmission, current diffusion, and ohmic contact with the second semiconductor.

[0045] Furthermore, in some embodiments, the passivation layer 500 is a silicon dioxide passivation layer. The passivation layer 500 is a silicon dioxide passivation layer, which can relieve thermal stress and prevent surface cracks from expanding; protect the LED chip and prevent other impurity atoms from being adsorbed on the chip surface, thereby reducing the leakage current on the LED surface; and insulate the NP electrode to avoid short circuits during operation.

[0046] Furthermore, in some embodiments, the thickness of the passivation layer is less than the thickness of the substrate layer. By reducing the distance from the top to the side, the capacitance of the device on the path from the top to the side is further increased, making it larger than the capacitance on the path from the top to the bottom, so that the capacitive reactance is smaller under high-frequency driving, so that the current on the path is increased, so that more carriers are injected to achieve light emission, and the turn-on voltage of the device is reduced.

[0047] Furthermore, in some embodiments, the side electrode 600 fully surrounds the surface of the passivation layer 500 facing away from the side of the epitaxial layer. At this time, a side electrode is formed. When the side electrode is connected to a low potential (for example, grounded), a "top-side" path is formed. Under the action of the electromagnetic field, the carriers may be deflected during transmission (compared to a simple vertical electric field), so that the carriers' transport distance in the active layer becomes longer, the recombination efficiency is improved, and thus the luminous intensity of the device is improved, and the luminous effect of the device is enhanced.

[0048] Furthermore, in some embodiments, the side electrode 600 covers the surface of the two side surfaces of the passivation layer 500 facing away from the epitaxial layer. At this time, two side electrodes are formed. When the two side electrodes are connected to a low potential (for example, grounded), two "top-side" paths are formed. Under the action of the electromagnetic field, the carriers may be deflected during the transmission process (compared to a simple vertical electric field), so that the carriers have a longer transport distance in the active layer than in the case of one side electrode, and the recombination efficiency is also higher, thereby better improving the luminous intensity of the device and enhancing the luminous effect of the device.

[0049] Furthermore, in some embodiments, the passivation layer 500 also covers a portion of the surface of the planar portion of the first semiconductor layer 200 that is not covered by the epitaxial layer and faces away from the substrate layer 100 .

[0050] Furthermore, in some embodiments, the side electrode 600 also extends to and partially covers the surface of the passivation layer 500 facing away from the second semiconductor 400 , and extends to and covers the surface of the passivation layer 500 facing away from the planar portion of the first semiconductor layer 200 .

[0051] By extending the side electrode 600 to partially cover the surface of the passivation layer 500 facing away from the second semiconductor 400, and extending and covering the surface of the planar portion of the passivation layer 500 facing away from the first semiconductor layer 200, the process flow can be simplified, and probe piercing and application of AC signals for testing can be facilitated. At the same time, the side electrode 600 can be connected to the outside of the device through a wire or other conductive structure, so that the side electrode 600 can be connected to a low potential (for example, grounding).

[0052] In one embodiment, Figure 3 As shown, the side electrode 600 fully encloses the surface of the passivation layer 500 facing away from the side of the epitaxial layer, and the side electrode 600 extends and partially covers the entire surface of the passivation layer 500 facing away from the second semiconductor 400, and a side electrode sheet is externally connected to the outside of the device. Through the external side electrode sheet, under the action of the electromagnetic field, the carrier input may be deflected, thereby improving the recombination efficiency, thereby improving the luminous intensity of the device and enhancing the luminous effect of the device.

[0053] In another embodiment, Figure 4As shown, the side electrode 600 covers the surface of the two opposite sides of the passivation layer 500 facing away from the epitaxial layer, and the side electrode 600 extends and partially covers the two opposite sides of the passivation layer 500 facing away from the second semiconductor 400, and two side electrode sheets are externally connected to the outside of the device. By arranging the two side electrodes on both sides, an alternating signal (single-ended or differential) can be introduced. Under the action of the electromagnetic field, the conductivity of the device material will change, thereby increasing current injection; at the same time, under the action of the electromagnetic field, the probability that the carrier input may be deflected is higher, further improving the recombination efficiency, thereby better improving the luminous intensity of the device and enhancing the luminous effect of the device.

[0054] Furthermore, in some embodiments, the first semiconductor layer 200 is n-type GaN, and the second semiconductor layer 400 is p-type GaN. In addition, the first semiconductor layer 200 may also be p-type GaN, and the second semiconductor layer 400 may be n-type GaN.

[0055] In this embodiment, the material of the side electrode 600 and the upper electrode 700 is metal, preferably, it can be gold (Au), silver (Ag), copper (Cu), titanium (Ti), nickel (Ni), tungsten (W), platinum (Pt) and other metals, which are not limited in this embodiment. The passivation layer 500 can be one or a combination of aluminum oxide (Al2O3), hafnium oxide (HfO2), silicon dioxide (SiO2), silicon nitride (Si3N4) or aluminum nitride (AlN). Preferably, the passivation layer 500 is a silicon dioxide passivation layer.

[0056] Example 2

[0057] refer to Figure 5 The present invention also provides a method for manufacturing an AC-driven LED device, which is used to manufacture the LED device of the above-mentioned embodiment 1. The method comprises the following steps:

[0058] S201, providing a substrate layer;

[0059] S202, forming a first semiconductor layer, wherein the first semiconductor layer is located on the surface of the substrate layer, the first semiconductor layer comprises a planar portion and a convex portion, and the convex portion is located on the surface of the planar portion facing away from the substrate layer;

[0060] S203, forming an active layer, wherein the active layer is located on a surface of the protruding portion of the first semiconductor layer facing away from the substrate layer;

[0061] S204, forming a second semiconductor layer, wherein the second semiconductor layer is located on a surface of the active layer facing away from the first semiconductor layer, and the conductivity type of the second semiconductor layer is opposite to that of the first semiconductor layer;

[0062] S205, forming a passivation layer, wherein the passivation layer is located on a surface of the second semiconductor layer facing away from the active layer and covers a side of the epitaxial layer, wherein the epitaxial layer is a protruding portion of the first semiconductor layer, the active layer, and the second semiconductor layer;

[0063] S206, forming a side electrode, wherein the side electrode is located on a surface of the passivation layer facing away from the side of the epitaxial layer

[0064] Further, in some embodiments, a method for manufacturing an AC-driven LED device includes the following steps: providing a substrate layer; epitaxially growing a first semiconductor layer, an active layer, and a second semiconductor layer in sequence on the surface of the substrate layer, wherein the first semiconductor layer includes a planar portion and a convex portion, and the convex portion is located on the surface of the planar portion facing away from the substrate layer; depositing the substrate layer on the surface of the second semiconductor layer facing away from the active layer, extending and covering the side of the epitaxial layer, and the epitaxial layer is the convex portion of the first semiconductor layer, the active layer, and the second semiconductor layer; then etching the portion of the passivation layer located on the surface of the second semiconductor layer facing away from the active layer to form a first opening, forming an upper electrode in the first opening, and the upper electrode is connected to the second semiconductor layer through the first opening; finally, forming a side electrode on the surface of the passivation layer facing away from the side of the epitaxial layer.

[0065] The method for preparing an AC-driven LED device provided by the present invention can prepare the AC-driven LED device provided by the present invention. The LED device will generate a certain tilt angle during the etching process, and the tilt angle naturally formed on the side of the epitaxial layer during the deposition and etching process is used to further deposit the passivation layer and the side electrode. By adding the side electrode, when the side electrode is connected to a low potential (for example, grounded), a "top-side" path is formed. Due to the lack of a substrate layer, the capacitance on the "top-side" path is larger than the capacitance on the "top-bottom" path, so that the capacitive reactance under high-frequency driving is smaller, so that the current on the path increases, thereby causing more carriers to be injected to achieve luminescence and reduce the turn-on voltage; at the same time, the low potential of the side electrode will cause the carrier to deflect during the transmission process (compared with a simple vertical electric field), so that the carrier transport distance in the active layer becomes longer, and the recombination probability increases, thereby improving the device luminescence intensity. In addition, under the influence of high-frequency electromagnetic waves, the conductivity of the semiconductor material in the prior art will also be affected, so that the overall impedance of the device is affected. The present invention can improve current injection, device luminous intensity, and device luminous effect under constant voltage working conditions by adjusting the frequency and amplitude of the electromagnetic field introduced into the device. Therefore, the AC-driven LED device provided by the present invention can effectively reduce the turn-on voltage of the LED device under AC drive, while increasing the injected current, increasing the device luminous intensity, and thus enhancing the device luminous effect.

[0066] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. An AC-driven LED device, It is characterized in that include: substrate layer; A first semiconductor layer, located on the surface of the substrate layer, the first semiconductor layer comprises a plane portion and a protruding portion, the protruding portion is located on the surface of the plane portion facing away from the substrate layer; An active layer, located on a surface of the protruding portion of the first semiconductor layer facing away from the substrate layer; A second semiconductor layer is located on a surface of the active layer facing away from the first semiconductor layer, the second semiconductor layer has a conductivity type opposite to that of the first semiconductor layer, wherein the second semiconductor layer on the top and the substrate layer on the bottom are suitable for connecting to AC electrodes respectively; The raised portion of the first semiconductor layer, the active layer and the second semiconductor layer constitute an epitaxial layer of the LED device; A passivation layer, located on a surface of the second semiconductor layer facing away from the active layer and covering a side of the epitaxial layer; The side electrode is located on the surface of the passivation layer facing away from the side of the epitaxial layer.

2. The AC-driven LED device according to claim 1, It is characterized in that A first opening is provided on a portion of the passivation layer located on a surface of the second semiconductor layer facing away from the active layer. The LED device is further provided with an upper electrode, and the upper electrode is connected to the second semiconductor layer through the first opening.

3. The AC-driven LED device according to claim 1, It is characterized in that A conductive layer is also arranged between the second semiconductor layer and the passivation layer, and a second opening is provided on a portion of the passivation layer located on a surface of the conductive layer facing away from the second semiconductor layer. The LED device is also provided with an upper electrode, and the upper electrode is connected to the conductive layer through the second opening.

4. The AC-driven LED device according to claim 3, It is characterized in that The conductive layer is an ITO conductive layer, and the passivation layer is a silicon dioxide passivation layer.

5. The AC-driven LED device according to claim 1, It is characterized in that The thickness of the passivation layer is smaller than the thickness of the substrate layer.

6. The AC-driven LED device according to claim 1, It is characterized in that The side electrode fully surrounds the surface of the passivation layer facing away from the side of the epitaxial layer.

7. The AC-driven LED device according to claim 1, It is characterized in that The side electrodes cover surfaces of the passivation layer that are opposite to the two side surfaces of the epitaxial layer.

8. The AC-driven LED device according to claim 6 or 7, It is characterized in that The passivation layer further covers a portion of the surface of the planar portion of the first semiconductor layer facing away from the substrate layer and not covered by the epitaxial layer.

9. The AC-driven LED device according to claim 8, It is characterized in that The side electrode further extends to and partially covers a surface of the passivation layer facing away from the second semiconductor, and extends to and covers a surface of the passivation layer facing away from the planar portion of the first semiconductor layer.

10. A method for manufacturing an AC-driven LED device, It is characterized in that The following steps are involved: providing a substrate layer; forming a first semiconductor layer, wherein the first semiconductor layer is located on the surface of the substrate layer, the first semiconductor layer comprises a planar portion and a convex portion, and the convex portion is located on the surface of the planar portion facing away from the substrate layer; forming an active layer, wherein the active layer is located on a surface of the protruding portion of the first semiconductor layer facing away from the substrate layer; forming a second semiconductor layer, wherein the second semiconductor layer is located on a surface of the active layer facing away from the first semiconductor layer, and the conductivity type of the second semiconductor layer is opposite to that of the first semiconductor layer; forming a passivation layer, the passivation layer being located on a surface of the second semiconductor layer facing away from the active layer and covering a side of the epitaxial layer, the epitaxial layer being a raised portion of the first semiconductor layer, the active layer and the second semiconductor layer; A side electrode is formed, wherein the side electrode is located on a surface of the passivation layer facing away from the side of the epitaxial layer.

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