Nanorod light emitting device, method of manufacturing the same, and display device including the same

Abstract

The invention provides a nanorod light emitting device, a method of manufacturing the same, and a display device including the same. The nanorod light-emitting device includes: a support layer; a first type semiconductor nanocore protruding from an upper surface of the support layer and including a semiconductor material doped in a first conductivity type; a mask layer on an upper surface of the support layer, extending to a first height of the first type semiconductor nanocore in a vertical direction, and adjacent to a surface of the first type semiconductor nanocore; a light emitting layer having a multi-quantum well structure adjacent to a portion of the first type semiconductor nanocore above the first height in the vertical direction; and a second type semiconductor layer adjacent to a surface of the light emitting layer and including a semiconductor material doped in a second conductivity type.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate to a nanorod light emitting device, a method of manufacturing the same, and a display apparatus including the nanorod light emitting device. Background Art

[0002] Compared with related light sources, light emitting diodes (LEDs) are light sources with advantages such as relatively long life, low power consumption, fast response speed, and environmental friendliness, and industrial demand is increasing due to these advantages. LEDs are used in various products such as backlights of lighting equipment and display devices.

[0003] Recently, micro-unit or nano-unit ultra-small LEDs using II-VI or III-V compound semiconductors are being developed. In addition, micro-LED displays in which ultra-small LEDs are directly applied as light-emitting elements of display pixels are being developed. However, when LEDs are miniaturized to micro-units or nano-units, the luminous efficiency of the LEDs may decrease. Summary of the invention

[0004] One or more example embodiments provide a nanorod light emitting device having a nanoscale diameter and improved light emitting efficiency, a method of manufacturing the same, and a display apparatus including the nanorod light emitting device.

[0005] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0006] According to one aspect of an example embodiment, a nanorod light emitting device is provided, comprising: a supporting layer; a first type semiconductor nanocore protruding from an upper surface of the supporting layer and comprising a semiconductor material doped to a first conductivity type; a mask layer on the upper surface of the supporting layer and extending in a vertical direction to a first height of the first type semiconductor nanocore and adjacent to a surface of the first type semiconductor nanocore; a light emitting layer having a multi-quantum well structure adjacent to a portion of the first type semiconductor nanocore above the first height in the vertical direction; and a second type semiconductor layer adjacent to the surface of the light emitting layer and comprising a semiconductor material doped to a second conductivity type.

[0007] The support layer and the first type semiconductor nanocore may be integrally formed.

[0008] The first end of the mask layer may have a tapered shape.

[0009] The first height may be greater than or equal to 5% of the height of the first type semiconductor nanocore.

[0010] The nanorod light emitting device may further include an insulating layer extending in a vertical direction from a lowermost upper surface of the mask layer to a second height of the first type semiconductor nanocore and adjacent to the mask layer and the light emitting layer.

[0011] The second height may be greater than the first height.

[0012] The first type semiconductor nanocore may include: a first portion having a uniform cross-sectional area in a horizontal direction perpendicular to the vertical direction; and a second portion having a cross-sectional area in the horizontal direction that decreases in the vertical direction as it moves away from the support layer.

[0013] A region of the light emitting layer on the second portion and a region of the second type semiconductor layer on the second portion may be a light emission disabled region.

[0014] The nanorod light emitting device may further include a hard mask layer on top of the first type semiconductor nanocores.

[0015] The nanorod light emitting device may further include a superlattice layer between the first type semiconductor nanocore and the light emitting layer.

[0016] The nanorod light emitting device may further include an electron blocking layer between the light emitting layer and the second type semiconductor layer.

[0017] The first type semiconductor nano-core, the light emitting layer, and the second type semiconductor layer may include Group III-V nitride semiconductor materials.

[0018] The nanorod light emitting device may be configured to emit red light, and the internal quantum efficiency of the nanorod light emitting device is greater than 20%.

[0019] According to another aspect of the example embodiment, a display device is provided, comprising: a plurality of pixel electrodes; a common electrode corresponding to the plurality of pixel electrodes; and a plurality of nanorod light-emitting devices connected between each of the plurality of pixel electrodes and the common electrode, wherein each of the plurality of nanorod light-emitting devices comprises: a supporting layer; a first type semiconductor nanocore protruding from an upper surface of the supporting layer and comprising a semiconductor material doped with a first conductivity type; a mask layer on the upper surface of the supporting layer and extending in a vertical direction to a first height of the first type semiconductor nanocore and adjacent to a surface of the first type semiconductor nanocore; a light-emitting layer having a multi-quantum well structure and adjacent to a portion of the first type semiconductor nanocore above the first height in the vertical direction; and a second type semiconductor layer adjacent to the surface of the light-emitting layer and comprising a semiconductor material doped with a second conductivity type.

[0020] According to another aspect of the example embodiment, a method for manufacturing a nanorod light-emitting device is provided, the method comprising: forming a first type semiconductor nanocore protruding from a support layer in a first direction; forming a mask layer adjacent to a lower side of the first type semiconductor nanocore; and growing a light-emitting structure layer from a surface of the first type semiconductor nanocore in a direction different from the first direction.

[0021] The formation of the first type semiconductor nanocores may include wet etching the semiconductor substrate.

[0022] The method may further include patterning the semiconductor substrate and the hard mask layer together after forming the hard mask layer on the semiconductor substrate.

[0023] The growth of the light emitting structure layer may include sequentially forming a superlattice layer, a light emitting layer, an electron blocking layer, and a second type semiconductor layer.

[0024] The method may further include, after the growth of the light emitting structure layer, disabling light emission of the light emitting structure layer formed on the semipolar surface on the top of the first type semiconductor nano core among the light emitting structure layer.

[0025] The method may further include forming an insulating layer adjacent to an end portion of the mask layer and the light emitting structure layer after growing the light emitting structure layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other aspects, features and advantages of example embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic cross-sectional view of a structure of a nanorod light emitting device according to an example embodiment;

[0028] Figure 2 is a schematic cross-sectional view of the structure of a nanorod light emitting device according to another example embodiment;

[0029] Figure 3 is a schematic cross-sectional view of the structure of a nanorod light emitting device according to another example embodiment;

[0030] Figure 4A , Figure 4B , Figure 4C , Figure 4D , Figure 4E , Figure 4F , Figure 4G , Figure 4H , Fig. 4I and Figure 4J is a diagram of a method of manufacturing a nanorod light emitting device according to an example embodiment;

[0031] Figure 5A , Figure 5B and Figure 5C is a diagram illustrating a method of manufacturing a nanorod light emitting device according to another example embodiment;

[0032] Fig. 6A , Figure 6B , Figure 6C , Fig.6D , Fig. 6E , Fig. 6F , Figure 6G , Figure 6H , Fig.6I and Figure 6J is a diagram illustrating a method of manufacturing a nanorod light emitting device according to another example embodiment;

[0033] Fig. 7A and Figure 7B is a micrograph of a nanorod light emitting device manufactured according to a method of manufacturing a nanorod light emitting device according to an example embodiment;

[0034] Figure 8 is a conceptual diagram schematically showing a configuration of a display device according to an example embodiment;

[0035] Fig. 9 is a schematic block diagram of an electronic device according to an example embodiment;

[0036] Fig.10 An example in which a display device according to an example embodiment is applied to a mobile device is shown;

[0037] Fig.11 An example in which the display device according to the example embodiment is applied to a vehicle display device is shown;

[0038] Fig.12 An example in which a display device according to an example embodiment is applied to augmented reality glasses or virtual reality glasses is shown;

[0039] Fig.13 shows an example in which the display device according to the example embodiment is applied to a sign; and

[0040] Fig.14 An example in which the display device according to the example embodiment is applied to a wearable display is shown. DETAILED DESCRIPTION

[0041] Now will be referred to in detail embodiment, its example is shown in the accompanying drawings, wherein the same reference numerals always refer to the same elements.In this regard, example embodiments can have different forms, and should not be construed as being limited to the description set forth herein.Therefore, example embodiments are described below only by reference to the accompanying drawings to illustrate various aspects.As used herein, the term "and / or" includes any and all combinations of one or more related listed items.When after a column of elements, a statement such as "at least one of ..." modifies the entire column of elements, without modifying the individual elements in the column.For example, the statement "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all a, b, and c.

[0042] Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings. In addition, example embodiments may be modified in various ways and may be embodied in many different forms. In the accompanying drawings, the same reference numerals always refer to the same elements, and the sizes of the elements in the accompanying drawings may be exaggerated for clarity and convenience of description.

[0043] When an element or layer is referred to as being “on” or “over” another element or layer, it can be directly on the other element or layer, or intervening elements or layers may be present.

[0044] Although the terms "first", "second", etc. may be used herein to describe various elements, these terms are only used to distinguish one element from another element. These terms do not limit the difference in materials or structures constituting the elements.

[0045] The singular form is also intended to include the plural form unless the context clearly indicates otherwise. Unless otherwise defined, when a component “includes” or “comprises” an element in the specification, it does not exclude other elements but may further include other elements.

[0046] Furthermore, in the specification, the term "unit" or "module" means a unit or module that processes at least one function or operation and may be implemented by hardware, software, or a combination of hardware and software.

[0047] The term "the" and similar terms may be used in both the singular and the plural.

[0048] With respect to the operations constituting the method, the operations may be performed in any suitable order unless the order of operations is clearly indicated or unless the context clearly indicates otherwise. Unless otherwise stated, the use of any and all examples or exemplary language provided herein is intended only to better illustrate the present disclosure and is not intended to limit the scope of the present disclosure.

[0049] Figure 1is a schematic cross-sectional view of the structure of a nanorod light emitting device 101 according to example embodiments.

[0050] The nanorod light emitting device 101 may include: a support layer 110; a mask layer 120, which is adjacent to and surrounds the surface of a first type semiconductor nanocore 111 below a predetermined height in a vertical direction (Z direction), the first type semiconductor nanocore protruding from the upper surface of the support layer 110 and including a semiconductor material doped to a first conductivity type; a light emitting layer 115, which is adjacent to and surrounds a portion of the first type semiconductor nanocore 111 not surrounded by the mask layer 120; and a second type semiconductor layer 117, which includes a semiconductor material doped to a second conductivity type. A superlattice layer 113 may be further formed between the first type semiconductor nanocore 111 and the light emitting layer 115, and an electron blocking layer 116 may be further formed between the light emitting layer 115 and the second type semiconductor layer 117.

[0051] The support layer 110 and the first type semiconductor nano core 111 may have an integrated structure based on the same semiconductor substrate. For example, the support layer 110 and the first type semiconductor nano core 111 may be formed by etching a gallium nitride (GaN) substrate doped with an n-type dopant. The material of the first type semiconductor nano core 111 is not limited thereto, but may include, for example, at least one semiconductor material selected from n-AlGaN, n-AlInGaN, n-AlGaN, and n-GaN. For example, silicon (Si) may be used as an n-type dopant.

[0052] The second type semiconductor layer 117 may include at least one semiconductor material selected from among p-AlGaN, p-AlInGaN, p-AlGaN, and p-GaN. For example, magnesium (Mg), zinc (Zn), or beryllium (Be) may be used as a p-type dopant.

[0053] The light emitting layer 115 may have a multi-quantum well (MQW) structure. The MQW structure is a structure in which a plurality of quantum well layers and a plurality of barrier layers are alternately arranged. Electrons and holes provided from the first type semiconductor nanocore 111 and the second type semiconductor layer 117 are recombined in the quantum well in the light emitting layer 115, so that light can be generated. The wavelength of light emitted from the light emitting layer 115 can be determined according to the energy band gap of the material constituting the quantum well in the light emitting layer 115. Considering the driving voltage and the luminous efficiency of the nanorod light emitting device 101, the thickness of the light emitting layer 115 or the number of quantum wells in the light emitting layer 115 can be appropriately selected.

[0054] The light emitting layer 115 may include a quantum well layer containing indium gallium nitride (InGaN) and a barrier layer containing GaN. The pair of quantum well layers and barrier layers are not limited thereto and may include InGaN / InGaN, indium gallium nitride / aluminum gallium nitride (InGaN / AlGaN), or indium gallium nitride / indium aluminum gallium nitride (InGaN / InAlGaN), but the composition ratio of each element may be appropriately adjusted. For example, the composition ratio of InGaN / InAlGaN may be appropriately adjusted. x Ga 1-x N (0.25≤x<1) quantum well layer and including In y Ga 1-y The barrier layer of N (0≤y<0.15) may form a pair. The content of indium (In) in the quantum well layer may be determined in consideration of the desired emission wavelength. In an example, the first type semiconductor nanocore 111, the light emitting layer 115, and the second type semiconductor layer 117 may include a III-V nitride semiconductor material.

[0055] The superlattice layer 113 may have a structure in which two thin films forming a pair are repeatedly arranged dozens of times. For example, a first layer including a material such as the first type semiconductor nanocore 111 and a second layer including a material such as the light emitting layer 115 may be alternately arranged dozens of times. For example, the first layer may include GaN, and the second layer may include In y Ga 1-y N(0≤y<0.15). The superlattice layer 113 can relieve stress caused by the lattice constant difference between the first type semiconductor nano core 111 and the light emitting layer 115 .

[0056] An electron blocking layer (EBL) 116 may be disposed between the light emitting layer 115 and the second type semiconductor layer 117. The electron blocking layer 116 may include a semiconductor material doped to the same conductivity type as the second type semiconductor layer 117.

[0057] In addition, a semiconductor layer doped to the first conductivity type may be further formed on the surface of the first type semiconductor nano core 111 .

[0058] like Figure 1As shown, the first type semiconductor nano core 111 may have a shape including a first portion R1 and a second portion R2, in which the cross-sectional area in the horizontal direction (D direction) perpendicular to the height direction (Z direction) is constant in the first portion R1, and in the second portion R2, the cross-sectional area in the horizontal direction perpendicular to the height direction decreases with the height. The first surface 111a of the first portion R1 is a non-polar surface, but the second surface 111b of the second portion R2 is a semi-polar surface, and therefore, the light emitting structure formed in the second surface 111b as an inclined surface may have a relatively low light emitting efficiency. In addition, the uppermost portion of the second portion R2 may have a low film quality because its forming material such as a group III semiconductor material may not move smoothly during its formation. In the nanorod light emitting device 101 according to the example embodiment, a light emitting forbidden region 119 may be formed on the second portion R2. The light emitting forbidden region 119 may be formed by increasing the point defect concentration by ion implantation in the light emitting structure formed on the second portion R2.

[0059] In the nanorod light emitting device 101 according to the example embodiment, the light emitting structure layer (ES) is formed at a position above a predetermined height of the first type semiconductor nano core 111. To this end, Figure 1 As shown, the mask layer 120 is formed to extend from the upper surface of the support layer 110 to the first height H1 of the first type semiconductor nano core 111 to surround the first type semiconductor nano core 111. Therefore, the light emitting structure layer ES is formed at a position equal to or higher than the first height H1 in the vertical direction (Z direction). One end of the mask layer 120, that is, the end at the first height H1 may have a tapered shape. This shape is attributed to the difference in etching rate of the photoresist material used in the process of forming the mask layer 120 to the first height H1. However, the shape of one end of the mask layer 120 is not limited thereto.

[0060] The mask layer 120 may include silicon oxide or silicon nitride as an insulating material, and may include, for example, silicon oxide (SiO 2 ), titanium oxide (TiO 2 ), silicon nitride (Si 3 N 4 ), aluminum oxide (Al 2 O 3 ), titanium nitride (TiN), aluminum nitride (AlN), zinc oxide (ZrO 2 ), titanium aluminum nitride (TiAlN), titanium silicon nitride (TiSiN), etc.

[0061] The first height H1 may be 5% or more of the height H of the first type semiconductor nano core 111 .

[0062] The purpose of forming the mask layer 120 in this manner is to reduce defects that may occur at the lower position of the first type semiconductor nanocore 111. An example of such a defect is, for example, the formation of abnormally large GaN. The first height H1 can be determined to be as small as possible to prevent such defects. For example, the first height H1 can be 5% or more, 30% or less, 20% or less, or 10% or less of the height H of the first type semiconductor nanocore 111.

[0063] The nanorod light emitting device 101 may further include an insulating layer 140 extending from the lowest upper surface of the mask layer 120 to the position of the second height H2 of the first type semiconductor nano core 111 and surrounding the mask layer 120 and the light emitting layer 115 .

[0064] The insulating layer 140 can prevent leakage current that may occur between the end of the mask layer 120 and the light emitting structure layer ES (for example, in the region marked as A). The second height H2 may be greater than the first height H1. The second height H2 is greater than the first height H1, but can be set as small as possible within a range that can prevent leakage current.

[0065] The nanorod light-emitting device 101 according to the example embodiment has a light-emitting structure surrounding the surface of the first type semiconductor nanocore 111 and growing in a direction perpendicular to the height direction (Z direction), wherein the m-plane (i.e., the non-polar surface) is the growth plane, and therefore, the internal quantum efficiency can be improved compared to a structure in which the c-plane (i.e., the polar surface) is the growth surface.

[0066] The first surface 111a of the first type semiconductor nanocore 111 is a non-polar surface, and the light-emitting layer 115 grown therefrom has almost no spontaneous polarization, so the quantum confinement Stark effect (QCSE) caused by the polarization field is reduced, and as a result, there is almost no electron / hole spatial separation problem. In addition, because the size of the formed structure is a nanometer scale in which strain is relieved, the polarization due to the piezoelectric field effect can be suppressed, thereby suppressing the quantum confinement Stark effect (QCSE). The piezoelectric field effect may also cause a blue shift due to an increase in current.

[0067] The nanorod light emitting device 101 according to the example embodiment has a structure that minimizes the cause of such a decrease in luminous efficiency, and thus, the luminous efficiency can be improved. In addition, the phenomenon of inducing crystal defects due to an increase in indium (In) content is also reduced, and thus, it is easier to maintain a uniform In content, and the problem of a relatively large half-maximum full width due to indium agglomeration is also reduced. As a result, the half-maximum full width of the emission spectrum can also be reduced.

[0068] In the case of a related embodiment, in which the nanocore is selectively grown in a structure without a mask layer 120 (such as the mask layer 120 provided in the nanorod light-emitting device 101 according to the example embodiment), and the light-emitting layer grows on a growth surface of a polar plane or a semi-polar plane, the light-emitting efficiency may be very low. For example, a red LED using AlGaInP as a light-emitting layer has high efficiency at a size greater than 100 μm×100 μm, but the efficiency decreases rapidly as the size decreases, and the external quantum efficiency (EQE) is less than 0.5%. An LED using InGaN as a light-emitting layer is relatively less affected by size, but in a red wavelength band where the indium (In) content increases, the internal quantum efficiency (IQE) is less than 20% and the external quantum efficiency (EQE) is less than 5% due to defects in lattice mismatch.

[0069] The internal quantum efficiency of the nanorod light emitting device 101 according to example embodiments may be greater than 20%, 25%, or higher, or may reach about 30%.

[0070] Even when the material of the light emitting layer 115 is set to emit red light, the internal quantum efficiency of the nanorod light emitting device 101 according to example embodiments may be greater than 20%, 25% or more, or may also reach about 30%.

[0071] Figure 2 is a schematic cross-sectional view of the structure of a nanorod light emitting device 102 according to another example embodiment.

[0072] According to another example embodiment, the nanorod light emitting device 102 is Figure 1 The nanorod light emitting device 101 is different in that no Figure 1 A light emission disabled region 119 is provided in the nanorod light emitting device 101 .

[0073] For example, the light emitting structure layer (ES) formed on the second surface 111b of the first type semiconductor nanocore 111 is as follows: Figure 5B Because the second surface 111b is a semi-polar surface, the light emitting structure formed on the semi-polar surface can present a higher effect than the light emitting structure formed on the polar surface. In addition, depending on the process, the quality of the thin film on the top of the first type semiconductor nano core 111 can be improved, and the light emitting structure of this part can also be used to contribute to light emission.

[0074] Figure 3 is a schematic cross-sectional view of the structure of a nanorod light emitting device 103 according to another example embodiment.

[0075] A nanorod light emitting device 103 according to another example embodiment differs from the above-described nanorod light emitting devices 101 and 102 in that the nanorod light emitting device 103 further includes a hard mask layer 160 on top of the first type semiconductor nanocore 111, the first type semiconductor nanocore 111 only including a first surface 111a, which is a non-polar surface.

[0076] FIG. 4A to FIG. 4J is a diagram illustrating a method of manufacturing a nanorod light emitting device according to example embodiments.

[0077] refer to Figure 4A , a semiconductor substrate SU may be provided. The semiconductor substrate SU may include an n-type doped semiconductor material. The semiconductor substrate SU may be, for example, an n-GaN substrate.

[0078] refer to Figure 4B , a structure in which a plurality of first type semiconductor nano cores 111 protrude is formed on the support layer 110 . Figure 4B The structure can be patterned and etched Figure 4A For example, in order to form this structure, a wet etching method using a tetramethylammonium hydroxide (TMAH) solution or a KOH solution as an etchant may be used.

[0079] refer to Figure 4C , a mask layer 120 is formed along the surface of the first type semiconductor nanocore 111. The mask layer 120 as an insulating material may include silicon oxide or silicon nitride, such as SiO 2 、TiO 2 、Si 3 N 4 、Al 2 O 3 、TiN、AlN、ZrO 2 , TiAlN, TiSiN, etc., and may be formed by using an ALD method. The mask layer 120 may be conformally formed along the surface of the support layer 110 and the surfaces of the plurality of first type semiconductor nano cores 111 .

[0080] refer to Figure 4D , forming a photoresist layer 130. The photoresist layer 130 having the height shown can be formed by coating a photoresist material and ashing.

[0081] refer to Figure 4E, a portion of the mask layer 120 that is higher than the photoresist layer 130 is etched. A wet etching method may be used that uses an etchant having a relatively high etching selectivity with respect to the material of the mask layer 120. Due to the difference in etching selectivity, the upper end of the mask layer 120 may be etched more than the photoresist layer 130, resulting in a tapered shape.

[0082] refer to Figure 4F , the photoresist layer 130 is removed.

[0083] refer to Figure 4G , the light emitting layer 115 is grown from the surface of the first type semiconductor nano-core 111. Figure 4G As shown, the superlattice layer 113, the light emitting layer 115, the electron blocking layer 116, and the second type semiconductor layer 117 may be sequentially formed in a shape surrounding the first surface 111a of the first type semiconductor nanocore 111. In order to form these semiconductor layers, for example, a hybrid vapor phase epitaxy (HVPE) method, a molecular beam epitaxy (MBE) method, a metal organic vapor phase epitaxy (MOVPE) method, a metal organic chemical vapor deposition (MOCVD) method, etc. may be used.

[0084] During the manufacturing process, the first type semiconductor nanocore 111 can further grow in the height direction, and thus can have a shape having a semi-polar second surface 111b in addition to a non-polar first surface 111a. The superlattice layer 113, the light emitting layer 115, the electron blocking layer 116, and the second type semiconductor layer 117 can also be sequentially formed on the second surface 111b.

[0085] refer to Figure 4H ,exist Figure 4G An insulating layer 140 is conformally formed on the structure shown. The insulating layer 140 is formed to prevent leakage current that may occur near the end of the mask layer 120 (ie, near the region marked A).

[0086] The insulating layer 140 may include, for example, zirconium oxide (ZrO), strontium oxide (SrO), magnesium oxide (MgO), barium oxide (BaO), cerium oxide (CeO 2 ), gadolinium oxide (Gd 2 O 3 ), calcium oxide (CaO), hafnium oxide (HfO 2 ), titanium oxide (TiO 2 ), aluminum oxide (AlO x ), barium nitride (BaN), silicon nitride (SiN), titanium nitride (TiN), cerium nitride (CeN), aluminum nitride (AlN), zinc selenide (ZnSe), zinc sulfide (ZnS), aluminum gallium nitride (AlGaN), or Al x Ga1-x As (x ≥ 0.9). The insulating layer 140 may be formed using an atomic layer deposition (ALD) method.

[0087] refer to Fig. 4I , the insulating layer 140 is etched to a predetermined height, and a light emission disabling process is performed with respect to the light emitting structure formed on the second surface 111 b of the first type semiconductor nano core 111 .

[0088] The insulating layer 140 may be etched using photoresist ashing and wet etching.

[0089] By performing the light emission disabling process using an ion implantation method, a portion of the light emitting structure where the point defect concentration increases becomes a light emission disabling region 119 .

[0090] refer to Figure 4J ,exist Fig. 4I The electrode layer 180 is formed on the structure of FIG. The material of the electrode layer 180 may include a transparent conductive material (such as ITO or IGZO) or a reflective metal material (such as Al).

[0091] The nanorod light emitting device 201 manufactured in this manner can be Figure 1 In the form of an array of multiple nanorod light emitting devices 101.

[0092] Figures 5A to 5C is a diagram illustrating a method of manufacturing a nanorod light emitting device according to another example embodiment.

[0093] Manufacturing method and reference according to example embodiments FIG. 4A to FIG. 4J The manufacturing method described differs in that no emission disabling process is performed.

[0094] For example, in Figure 5A In the structure fabricated as shown, both the first surface 111a (which is a non-polar surface) and the second surface 111b (which is a semi-polar surface) of the first type semiconductor nanocore 111 can be utilized.

[0095] like Figure 5B As shown, the insulating layer 140 may be formed to prevent leakage current near one end adjacent to the mask layer 120 .

[0096] like Figure 5C As shown, an electrode layer 180 is further formed. The nanorod light emitting device 202 manufactured in this way can be Figure 2 In the form of an array of multiple nanorod light emitting devices 102.

[0097] FIG. 6A to FIG. 6J is a diagram illustrating a method of manufacturing a nanorod light emitting device 103 according to another example embodiment.

[0098] refer to Fig. 6A , a hard mask layer 160 is formed on the semiconductor substrate SU.

[0099] The semiconductor substrate SU may include an n-type doped semiconductor material. The semiconductor substrate SU may include, for example, an n-GaN substrate.

[0100] The hard mask layer 160 may include the same material as the mask layer 120 described above, or may select a material having an etching selectivity lower than that of the mask layer 120. The hard mask layer 160 may include, for example, silicon oxide (SiO 2 ) single layer or SiO 2 / Al double layer.

[0101] Figure 6B The structure can be patterned and etched Fig. 6A For example, a wet etching method using a tetramethylammonium hydroxide (TMAH) solution or a potassium hydroxide (KOH) solution as an etchant may be used. Figure 6B A structure in which a plurality of first type semiconductor nano cores 111 protrude is provided on the support layer 110. A patterned hard mask layer 160 remains on top of the first type semiconductor nano cores 111.

[0102] refer to Figure 6C , a mask layer 120 is formed along the surface of the first type semiconductor nanocore 111. The mask layer 120 as an insulating material may include silicon oxide or silicon nitride, such as SiO 2 、TiO 2 、Si 3 N 4 、Al 2 O 3 、TiN、AlN、ZrO 2 , TiAlN, TiSiN, etc., and may be formed by using an ALD method. The mask layer 120 may be conformally formed along the surface of the support layer 110 and the surfaces of the plurality of first type semiconductor nano cores 111 .

[0103] refer to Fig.6D , forming a photoresist layer 130. The photoresist layer 130 having the height shown can be formed by coating a photoresist material and ashing.

[0104] refer to Fig. 6E , a portion of the mask layer 120 located at a higher height than the photoresist layer 130 is etched. A wet etching method using an etchant having a high etching selectivity with respect to the material of the mask layer 120 may be used. Due to the difference in etching selectivity, the upper end of the mask layer 120 may be etched more than the photoresist layer 130, resulting in a tapered shape.

[0105] refer to Fig. 6F , the photoresist layer 130 is removed. Therefore, a structure including the mask layer 120 covering the lower side of the first type semiconductor nano core 111 and the hard mask layer 160 covering the top of the first type semiconductor nano core 111 is formed.

[0106] refer to Figure 6G , the light emitting layer 115 is grown from the surface of the first type semiconductor nano-core 111. Fig. 6F As shown, the superlattice layer 113 , the light emitting layer 115 , the electron blocking layer 116 , and the second type semiconductor layer 117 may be sequentially formed in a shape surrounding the first surface 111 a of the first type semiconductor nano core 111 .

[0107] In the process of manufacturing these semiconductor layers, since the hard mask layer 160 is formed on the top of the first type semiconductor nano core 111, the first type semiconductor nano core 111 may not grow in the height direction (Z direction). Therefore, the superlattice layer 113, the light emitting layer 115, the electron blocking layer 116, and the second type semiconductor layer 117 are sequentially formed using the first surface 111a as a non-polar surface as a growth surface.

[0108] refer to Figure 6H ,exist Figure 6G An insulating layer 140 is conformally formed on the structure shown. The insulating layer 140 is formed to prevent leakage current that may occur near the end of the mask layer 120.

[0109] The insulating layer 140 may include, for example, ZrO, SrO, MgO, BaO, CeO 2 , Gd 2 O 3 , CaO, HfO 2 、TiO 2 、AlO x , BaN, SiN, TiN, CeN, AlN, ZnSe, ZnS, AlGaN or Al x Ga 1-x As (x ≥ 0.9). The insulating layer 140 may be formed by using an atomic layer deposition (ALD) method.

[0110] refer to Fig.6I , the insulating layer 140 is etched to a predetermined height. Photoresist ashing and wet etching may be used to etch the insulating layer 140.

[0111] refer to Figure 6J ,exist Fig.6I The electrode layer 180 is formed on the structure. The material of the electrode layer 180 can be a transparent conductive material or a reflective metal material.

[0112] The nanorod light emitting device 203 manufactured in this manner can be Figure 3 In the form of an array of multiple nanorod light emitting devices 103 .

[0113] Fig. 7A and Figure 7B A micrograph of a nanorod light emitting device manufactured according to a method of manufacturing a nanorod light emitting device according to example embodiments is shown.

[0114] Figure 7B yes Fig. 7A A magnified photo of a portion of. Fig. 7A and Figure 7B It was shown that a nanorod light-emitting device having a diameter of about 1 μm or less can be realized by the above-mentioned manufacturing method.

[0115] The nanorod light emitting devices 101, 102, and 103 according to the above exemplary embodiments can be used in various applications. In particular, the nanorod light emitting devices can be used as light emitting elements in pixels of next generation display devices. For example, Figure 8 is a conceptual diagram schematically showing a configuration of a display device using a nanorod light emitting device according to an example embodiment. Figure 8 The display device 2000 may include a plurality of first pixel electrodes 2002B, a first common electrode 2003B corresponding to the plurality of first pixel electrodes 2002B, a plurality of second pixel electrodes 2002G, a second common electrode 2003G corresponding to the plurality of second pixel electrodes 2002G, a plurality of third pixel electrodes 2002R, a third common electrode 2003R corresponding to the plurality of third pixel electrodes 2002B, a plurality of first nanorod light-emitting devices 100B connected between each first pixel electrode 2002B and the first common electrode 2003B, a plurality of second nanorod light-emitting devices 100G connected between each second pixel electrode 2002G and the second common electrode 2003G, and a plurality of third nanorod light-emitting devices 100R connected between each third pixel electrode 2002R and the third common electrode 2003R.

[0116] For example, the first nanorod light emitting device 100B can be configured to emit blue light, the second nanorod light emitting device 100G can be configured to emit green light, and the third nanorod light emitting device 100R can be configured to emit red light. In addition, a first pixel electrode 2002B can form a blue sub-pixel together with the first common electrode 2003B, a second pixel electrode 2002G can form a green sub-pixel together with the second common electrode 2003G, and a third pixel electrode 2002R can form a red sub-pixel together with the third common electrode 2003R.

[0117] The first nanorod light emitting device 100B, the second nanorod light emitting device 100G, and the third nanorod light emitting device 100R may all be any one of the nanorod light emitting devices 101 , 102 , and 103 described above.

[0118] The nanorod light emitting devices 101, 102, and 103 according to the above exemplary embodiments can be applied to display devices of various sizes and various uses without limitation. For example, Figures 9 to 14 Various devices including a display device to which the nanorod light emitting device according to example embodiments is applied are shown.

[0119] first, Fig. 9 is a schematic block diagram of an electronic device according to an example embodiment. Fig. 9 , an electronic device 8201 may be provided in a network environment 8200. In the network environment 8200, the electronic device 8201 may communicate with another electronic device 8202 through a first network 8298 (short-range wireless communication network, etc.), or may communicate with another electronic device 8204 and / or a server 8208 through a second network 8299 (long-range wireless communication network). The electronic device 8201 may communicate with the electronic device 8204 through the server 8208. The electronic device 8201 may include a processor 8220, a memory 8230, an input device 8250, an audio output device 8255, a display device 8260, an audio module 8270, a sensor module 8276 and an interface 8277, a haptic module 8279, a camera module 8280, a power management module 8288, a battery 8289, a communication module 8290, a user identification module 8296, and / or an antenna module 8297. In the electronic device 8201, some of these components may be omitted or other components may be added. Some of these components may be implemented as an integrated circuit. For example, the sensor module 8276 (fingerprint sensor, iris sensor, light sensor, etc.) may be implemented by being embedded in the display device 8260 (display, etc.).

[0120] The processor 8220 may run software (program 8240, etc.) to control one or more other components (hardware, software components, etc.) of the electronic device 8201 connected to the processor 8220, and may perform various data processing or operations. As part of data processing or calculation, the processor 8220 may load instructions and / or data received from other components (sensor module 8276, communication module 8290, etc.) into the volatile memory 8232, process the commands and / or data stored in the volatile memory 8232, and store the result data in the non-volatile memory 8234. The non-volatile memory 8234 may include an internal memory 8236 installed in the electronic device 8201 and a removable external memory 8238. The processor 8220 may include a main processor 8221 (central processing unit, application processor, etc.) and an auxiliary processor 8223 (graphics processing unit, image signal processor, sensor hub processor, communication processor, etc.), and the auxiliary processor 8223 may operate independently or together with the main processor 8221. The auxiliary processor 8223 may use less power than the main processor 8221 and may perform specialized functions.

[0121] When the main processor 8221 is in a suspended state (sleep state), the auxiliary processor 8223 can replace the main processor 8221 to control functions and / or states related to certain components of the electronic device 8201 (e.g., display device 8260, sensor module 8276, communication module 8290), or when the main processor 8221 is in an active state (application running state), the auxiliary processor 8223 can control functions and / or states related to certain components of the electronic device 8201 (e.g., display device 8260, sensor module 8276, communication module 8290) together with the main processor 8221. The auxiliary processor 8223 (image signal processor, communication processor, etc.) can be implemented as part of other functionally related components (camera module 8280, communication module 8290, etc.).

[0122] The memory 2230 may store various data required by the components (processor 8220, sensor module 8276, etc.) of the electronic device 8201. The data may include, for example, input data and / or output data of software (such as program 8240) and instructions related to commands. The memory 8230 may include a volatile memory 8232 and / or a non-volatile memory 8234.

[0123] The program 8240 may be stored as software in the memory 8230 and may include an operating system 8242 , middleware 8244 , and / or an application program 8246 .

[0124] The input device 8250 may receive commands and / or data to be used in components of the electronic device 8201 (such as the processor 8220) from outside the electronic device 8201 (such as a user). The input device 8250 may include a remote controller, a microphone, a mouse, a keyboard, and / or a digital pen (e.g., a stylus pen, etc.).

[0125] The sound output device 8255 can output sound signals to the outside of the electronic device 8201. The sound output device 8255 can include a speaker and / or a receiver. The speaker can be used for general purposes, such as multimedia playback or recording playback, and the receiver can be used to receive incoming calls. The receiver can be integrated as a part of the speaker, or implemented as a separate independent device.

[0126] The display device 8260 can visually provide information to the outside of the electronic device 8201. The display device 8260 may include a display, a holographic device or a projector, and a control circuit for controlling the corresponding device. The display device 8260 may include any one of the above-mentioned nanorod light-emitting devices 100, 101 and 102 or a light-emitting device modified therefrom as a display pixel. The display device 8260 may further include a touch circuit configured to detect a touch and / or a sensor circuit (such as a pressure sensor, etc.) configured to measure the strength of the force generated by the touch.

[0127] The audio module 8270 can convert sound into an electrical signal, or vice versa, convert an electrical signal into sound. The audio module 8270 can obtain sound through the input device 8250, or can output sound through the sound output device 8255 and / or a speaker and / or earphone of another electronic device (e.g., electronic device 8202) directly or wirelessly connected to the electronic device 8201.

[0128] The sensor module 8276 may detect an operating state (power, temperature, etc.) or an external environment state (user state, etc.) of the electronic device 8201, and may generate an electrical signal and / or data value corresponding to the detected state. The sensor module 8276 may include a gesture sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, and / or an illumination sensor.

[0129] The interface 8277 may support one or more designated protocols, and the electronic device 8201 may use the designated protocols to directly or wirelessly connect the electronic device 8201 to another electronic device (e.g., the electronic device 8102). The interface 8277 may include a high-definition multimedia interface (HDMI), a universal serial bus (USB) interface, an SD card interface, and / or an audio interface.

[0130] The connection end 8278 may include a connector through which the electronic device 8201 can be physically connected to another electronic device (such as the electronic device 8202). The connection end 8278 may include an HDMI connector, a USB connector, an SD card connector, and / or an audio connector (e.g., a headphone connector).

[0131] The haptic module 8279 may convert the electrical signal into mechanical stimulation (vibration, motion, etc.) or electrical stimulation that the user may sense through touch or kinesthetic sense. The haptic module 8279 may include a motor, a piezoelectric element, and / or an electrical stimulation device.

[0132] The camera module 8280 can capture still images and moving images. The camera module 8280 may include a lens assembly including one or more lenses, an image sensor, an image signal processor, and / or a flash. The lens assembly included in the camera module 8280 may collect light emitted from an object as an image capture target.

[0133] The power management module 8288 may manage power supplied to the electronic device 8201. The power management module 8288 may be implemented as a part of a power management integrated circuit (PMIC).

[0134] The battery 8289 may supply power to the components of the electronic device 8201. The battery 8289 may include a non-rechargeable primary battery, a rechargeable secondary battery, and / or a fuel cell.

[0135] The communication module 8290 can establish a direct (wired) communication channel and / or a wireless communication channel between the electronic device 8201 and other electronic devices (electronic device 8202, electronic device 8204, server 8208, etc.), and can support communication through the established communication channel. The communication module 8290 may include one or more communication processors (e.g., application processors) that operate independently of the processor 8220, and support direct communication and / or wireless communication. The communication module 8290 may include a wireless communication module 8292 (cellular communication module, short-range wireless communication module, global navigation satellite system (GNSS, etc.) communication module) and / or a wired communication module 8294 (local area network (LAN) communication module or power line communication module, etc.). Among these communication modules, the corresponding communication module can communicate with other electronic devices through a first network 8298 (short-range communication network, such as Bluetooth, WiFi Direct or Infrared Data Association (IrDA)) or a second network 8299 (telecommunication network, such as a cellular network, the Internet or a computer network (LAN and WAN, etc.)). Various types of communication modules may be integrated into one component (single chip, etc.) or implemented as multiple components (multiple chips) separated from each other. The wireless communication module 8292 may identify and authenticate the electronic device 8201 within a communication network (such as the first network 8298 and / or the second network 8299) by using user information (such as an international mobile subscriber identifier (IMSI)) stored in the user identification module 8296.

[0136] The antenna module 8297 can send signals and / or power to the outside (other electronic devices, etc.), or receive signals and / or power from the outside (other electronic devices, etc.). The antenna may include a radiator having a conductive pattern formed on a substrate (PCB, etc.). The antenna module 8297 may include one or more antennas. When multiple antennas are included in the antenna module 2297, the communication module 8290 can select an antenna suitable for a communication method used in a communication network such as a first network 8298 and / or a second network 8299 from the multiple antennas. Signals and / or power can be sent or received between the communication module 8290 and other electronic devices through the selected antenna. In addition to the antenna, other components (RFIC, etc.) may be included as part of the antenna module 8297.

[0137] Some components are connected to each other through a communication method between peripheral devices (bus, general purpose input and output (GPIO), serial peripheral interface (SPI), mobile industry processor interface (MIPI), etc.) and can exchange signals (commands, data, etc.).

[0138] Commands or data may be sent or received between the electronic device 8201 and the external electronic device 8204 through the server 8208 connected to the second network 8299. The other electronic devices 8202 and 8204 may be devices of the same or different types as the electronic device 8201. All or some operations performed on the electronic device 8201 may be performed on one or more other electronic devices 8202, 8204, and 8208. For example, when the electronic device 8201 needs to perform a certain function or service, the electronic device 8201 may request one or more other electronic devices to perform some or all functions or services instead of performing the function or service itself. One or more other electronic devices that have received the request may run additional functions or services related to the request and send the execution results to the electronic device 8201. To this end, cloud computing, distributed computing, and / or client-server computing technologies may be used.

[0139] Fig.10 An example of applying the display device according to the example embodiment to a mobile device is shown. The mobile device 9100 may include a display device 9110, and the display device 9110 may include any one of the above-mentioned nanorod light-emitting devices 101, 102, and 103 or a light-emitting device having a structure modified therefrom as a pixel. The display device 9110 may have a foldable structure, for example, a multi-foldable structure.

[0140] Fig.11 An example of a display device according to an example embodiment being applied to a vehicle display device is shown. The display device may be a head-up display device 9200 for a vehicle, and may include a display 9210 provided in one area of ​​the vehicle and an optical path changing member 9220 that converts an optical path so that a driver can view an image generated by the display 9210.

[0141] Fig.12 An example in which the display device according to the example embodiment is applied to augmented reality glasses or virtual reality glasses is shown. The augmented reality glasses 9300 may include a projection system 9310 that forms an image and an element 9320 that guides the image from the projection system 9310 into the user's eyes. The projection system 9310 may include any one of the above-mentioned nanorod light emitting devices 101, 102, and 103, or a light emitting device having a structure modified therefrom.

[0142] Fig.13 An example in which the display device according to the exemplary embodiment is applied to a sign is shown. The sign 9400 may be used for outdoor advertising using a digital information display, and the advertising content may be controlled through a communication network. The sign 9400 may be displayed by, for example, referring to Fig. 9 The electronic device described is implemented.

[0143] Fig.14 An example in which the display device according to the example embodiment is applied to a wearable display is shown. The wearable display 9500 may include any one of the above-mentioned nanorod light-emitting devices 101, 102, and 103, or include a light-emitting device having a structure modified therefrom, and may be manufactured by referring to Fig. 9 The electronic device described is implemented.

[0144] The display device according to the embodiment may also be applied to various products such as a rollable television (TV) and a stretchable display.

[0145] The nanorod light-emitting device includes a light-emitting layer grown on a non-polar surface, and therefore, the light-emitting efficiency is relatively high and the full width at half maximum of the light-emitting spectrum can be reduced.

[0146] According to the above-mentioned method of manufacturing a nanorod light-emitting device, a light-emitting structure including a high-quality semiconductor thin film with high uniformity and a small number of defects can be realized.

[0147] The nanorod light-emitting device can be used as a display pixel in various types of electronic devices.

[0148] The above-mentioned nanorod light-emitting device, its manufacturing method and the display device including the nanorod light-emitting device have been described with reference to the embodiments shown in the accompanying drawings. However, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure. Therefore, the example embodiments should be considered only in a descriptive sense and not for limiting purposes. The scope of the present disclosure is not limited by the detailed description of the present disclosure, but by the appended claims, and all differences within the scope will be interpreted as included in the present disclosure.

[0149] It should be understood that the example embodiments described herein should be considered in a descriptive sense only and not for limiting purposes. The description of features or aspects within each example embodiment should generally be considered applicable to other similar features or aspects in other embodiments. Although example embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the appended claims and their equivalents.

[0150] CROSS-REFERENCE TO RELATED APPLICATIONS

[0151] This application claims the priority of Korean Patent Application No. 10-2023-0103102 filed in the Korean Intellectual Property Office on August 7, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A nanorod light-emitting device, comprising: Support layer; a first type semiconductor nanocore protruding from the upper surface of the support layer and comprising a semiconductor material doped to a first conductivity type; a mask layer on the upper surface of the support layer and extending in a vertical direction to a first height of the first type semiconductor nanocore and adjacent to a surface of the first type semiconductor nanocore; a light emitting layer having a multi-quantum well structure, adjacent to a portion of the first type semiconductor nanocore above the first height in the vertical direction; as well as The second type semiconductor layer is adjacent to the surface of the light emitting layer and includes a semiconductor material doped into a second conductivity type. 2 . The nanorod light-emitting device according to claim 1 , wherein the support layer and the first type semiconductor nanocore are formed integrally. The nanorod light emitting device according to claim 1 , wherein the first end of the mask layer has a tapered shape. 4 . The nanorod light emitting device of claim 1 , wherein the first height is greater than or equal to 5% of the height of the first type semiconductor nanocore.

5. The nanorod light-emitting device according to claim 1, further comprising an insulating layer, which extends from the lowest upper surface of the mask layer to the second height of the first type semiconductor nanocore in the vertical direction and is adjacent to the mask layer and the light-emitting layer. The nanorod light-emitting device according to claim 5 , wherein the second height is greater than the first height.

7. The nanorod light emitting device according to claim 1, wherein the first type semiconductor nanocore comprises: A first portion having a uniform cross-sectional area in a horizontal direction perpendicular to the vertical direction; as well as The second portion has a cross-sectional area in the horizontal direction that decreases in the vertical direction as it moves away from the support layer. 8 . The nanorod light emitting device according to claim 7 , wherein a region of the light emitting layer on the second portion and a region of the second type semiconductor layer on the second portion are light emission disabled regions.

9. The nanorod light emitting device of claim 1, further comprising a hard mask layer on top of the first type semiconductor nanocore.

10. The nanorod light emitting device according to claim 1, further comprising a superlattice layer between the first type semiconductor nanocore and the light emitting layer. 11 . The nanorod light emitting device according to claim 1 , further comprising an electron blocking layer between the light emitting layer and the second type semiconductor layer.

12. The nanorod light emitting device of claim 1, wherein the first type semiconductor nanocore, the light emitting layer, and the second type semiconductor layer comprise III-V nitride semiconductor materials.

13. The nanorod light emitting device of claim 1, wherein the nanorod light emitting device is configured to emit red light, and an internal quantum efficiency of the nanorod light emitting device is greater than 20%.

14. A display device, comprising: a plurality of pixel electrodes; a common electrode corresponding to the plurality of pixel electrodes; as well as A plurality of nanorod light emitting devices are connected between each pixel electrode of the plurality of pixel electrodes and the common electrode, Each of the plurality of nanorod light-emitting devices comprises: Support layer; a first type semiconductor nanocore protruding from the upper surface of the support layer and comprising a semiconductor material doped to a first conductivity type; a mask layer on the upper surface of the support layer and extending in a vertical direction to a first height of the first type semiconductor nanocore and adjacent to a surface of the first type semiconductor nanocore; a light emitting layer having a multi-quantum well structure adjacent to a portion of the first type semiconductor nanocore above the first height in the vertical direction; and The second type semiconductor layer is adjacent to the surface of the light emitting layer and includes a semiconductor material doped into a second conductivity type.

15. A method for manufacturing a nanorod light-emitting device, the method comprising: forming a first type of semiconductor nanocore protruding from the support layer in a first direction; forming a mask layer adjacent to an underside of the first type semiconductor nanocore; as well as A light emitting structure layer is grown from the surface of the first type semiconductor nanocore in a direction different from the first direction.

16. The method of claim 15, wherein the forming of the first type semiconductor nanocores comprises wet etching a semiconductor substrate. 17 . The method of claim 16 , further comprising patterning the semiconductor substrate and the hard mask layer together after forming the hard mask layer on the semiconductor substrate. 18 . The method according to claim 15 , wherein the growing of the light emitting structure layer comprises sequentially forming a superlattice layer, a light emitting layer, an electron blocking layer, and a second type semiconductor layer. 19 . The method of claim 18 , further comprising, after the growth of the light emitting structure layer, disabling light emission of the light emitting structure layer formed on a semipolar surface on top of the first type semiconductor nano core among the light emitting structure layer. 20 . The method of claim 15 , further comprising forming an insulating layer adjacent to an end portion of the mask layer and the light emitting structure layer after growing the light emitting structure layer.

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