Two-dimensional material assisted epitaxy of red light emitters

Abstract

Methods of forming red light emitters via two-dimensional (2D) material assisted epitaxy and related articles, devices, and systems are generally described.

Description

[0001] TWO-DIMENSIONAL MATERIAL ASSISTED EPITAXY OF RED LIGHT EMITTERS

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 683,151, filed August 14, 2024, and entitled “TWO-DIMENSIONAL MATERIAL ASSISTED EPITAXY OF RED LIGHT EMITTERS,” which is incorporated herein by reference in its entirety for all purposes.

[0004] TECHNICAL FIELD

[0005] Methods of forming red light emitters via two-dimensional (2D) material assisted epitaxy and related articles, devices, and systems are generally described.

[0006] SUMMARY

[0007] Generally described herein are methods of forming red light emitters via 2D material assisted epitaxy and related articles, devices, and systems. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0008] According to some embodiments, a method is described. In certain embodiments, the method comprises forming a red-emitting indium gallium nitride (InGaN) layer over an InGaN buffer layer that is over a two-dimensional (2D) material that is over a substrate. In some embodiments, the red-emitting InGaN layer and the substrate have a percent lattice mismatch of at least 0.1%. In certain embodiments, an indium content of the red-emitting InGaN layer is greater than an indium content of the InGaN buffer layer.

[0009] According to certain embodiments, an article is described. In some embodiments, the article comprises an InGaN buffer layer and a red-emitting InGaN layer over the InGaN buffer layer, wherein the InGaN buffer layer has a strain relaxation greater than or equal to 80%.

[0010] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:

[0013] FIG. 1 shows a process flow schematic diagram representing methods comprising forming a red-emitting indium gallium nitride (InGaN) layer over an InGaN buffer layer that is over a 2D material that is over a first substrate and transferring the red-emitting InGaN layer and the InGaN buffer layer to a second substrate, in accordance with certain embodiments.

[0014] FIG. 2 shows a process flow schematic diagram representing a method comprising separating a red-emitting InGaN layer and an InGaN buffer layer from a 2D material that is over a first substrate and transferring the red-emitting InGaN layer and the InGaN buffer layer from the 2D material that is over the first substrate to a second substrate, in accordance with certain embodiments.

[0015] FIG. 3 shows a schematic diagram of an article comprising a red-emitting InGaN layer that is over an InGaN buffer layer that is over a 2D material that is over a substrate, in accordance with certain embodiments.

[0016] FIG. 4 shows a schematic diagram of an article comprising a red-emitting InGaN layer that is over an InGaN buffer layer, in accordance with certain embodiments.

[0017] FIG. 5 shows a schematic diagram of an article comprising a red-emitting InGaN layer that is over an InGaN buffer layer that is over a second substrate, in accordance with certain embodiments.

[0018] FIG. 6A shows a schematic diagram of a 2D material comprising amorphous boron nitride (aBN) and / or amorphous graphene (aGr) that is over a substrate comprising a Ill-nitride and / or sapphire, in accordance with certain embodiments.

[0019] FIG. 6B shows a schematic diagram of a 2D material comprising a graphene buffer layer (GBL) that is over a substrate comprising 4H-SiC, in accordance with certain embodiments.

[0020] FIG. 7 shows a scanning electron microscopy (SEM) image (bottom left), Raman spectra (top left and bottom right), and a X-ray photoelectron (XPS) spectrum (top right) of various 2D materials over various substrates, in accordance with certain embodiments.

[0021] FIG. 8A shows, in accordance with certain embodiments, a SEM image of a surface of an InGaN buffer layer formed over a 2D material that is over a substrate. FIGS. 8B-8C show, in accordance with certain embodiments, a comparison of reciprocal spacing mapping images of an InGaN buffer layer formed: (i) over a substrate (FIG. 8B); and (ii) over a 2D material that is over a substrate (FIG. 8C).

[0022] FIG. 9 shows an enlarged and annotated version of the reciprocal spacing mapping image of the InGaN buffer layer formed over the 2D material that is over the substrate shown in FIG. 8C, in accordance with certain embodiments.

[0023] FIG. 10 shows a reciprocal spacing mapping image of an InGaN buffer layer formed over a 2D material that is over a substrate.

[0024] DETAILED DESCRIPTION

[0025] Methods of forming red light emitters via two-dimensional (2D) material assisted epitaxy and related articles, devices, and systems are generally described. In certain embodiments, a method comprises forming a red-emitting indium gallium nitride (InGaN) layer over an InGaN buffer layer that is over a 2D material that is over a substrate. The methods described herein may advantageously be utilized with a wide variety of substrates, including substrates that are lattice-mismatched with the red-emitting InGaN layer. The InGaN buffer layer, which may be formed over the 2D material that is over the substrate, may have an advantageously high strain relaxation percentage and low dislocation density due to its 2D material assisted formation. For example, in some embodiments, the InGaN buffer layer may have an advantageously low number of defects such as edge dislocations, screw dislocations, threading dislocations, and / or anti-phase boundaries (APBs). The red-emitting InGaN layer may be subsequently formed over the strain relaxed InGaN buffer layer. In certain embodiments, an indium content of the red- emitting InGaN layer is greater than an indium content of the InGaN buffer layer such that the red-emitting InGaN layer is configured to emit light at a wavelength corresponding to red light. As used herein, “red light” refers to electromagnetic radiation having a wavelength of from 620 nm to 750 nm.

[0026] In certain embodiments, the red-emitting InGaN layer and the InGaN buffer layer may be separated from the 2D material that is over the substrate. The red-emitting InGaN layer and the InGaN buffer layer may, in some embodiments, be transferred to a second substrate for integration into a device, such as a light emitting diode (LED) device (e.g., a multicolor or full color LED device). Certain methods described herein therefore advantageously address deficiencies in the field of fabricating red-emitting InGaN-based LEDs by overcoming issues associated with the large lattice mismatch between the InGaN layer and the growth substrate (e.g., Ill-nitride growth substrate), e.g., via use of the 2D material and the strain relaxed InGaN buffer layer. As a result, certain of the articles described herein (e.g., articles comprising a red- emitting InGaN layer over an InGaN buffer layer) can replace conventional Ill-arsenic and / or III-phosphide materials traditionally used as red emitters in LED devices.

[0027] According to some embodiments, a method comprises forming a red-emitting InGaN layer over an InGaN buffer layer that is over a 2D material that is over a substrate. FIG. 1 shows a process flow schematic diagram representing methods comprising forming a red-emitting InGaN layer over an InGaN buffer layer that is over a 2D material that is over a first substrate and transferring the red-emitting InGaN layer and the InGaN buffer layer to a second substrate, in accordance with certain embodiments.

[0028] In certain embodiments, the method comprises forming a 2D material over a substrate. In some embodiments, as shown in FIG. 1, the 2D material is grown over the substrate. For example, in certain embodiments, the 2D material is grown directly over the substrate.

[0029] In certain embodiments, forming the 2D material over the substrate comprises epitaxially growing the 2D material. According to some embodiments, forming the 2D material over the substrate comprises growing the 2D material by molecular beam epitaxy (MBE) or chemical vapor deposition (CVD) (e.g., metal-organic chemical vapor deposition (MOCVD)).

[0030] In other embodiments, although not shown in FIG. 1, the 2D material is grown (e.g., epitaxially grown) on a separate substrate and subsequently transferred over the substrate (e.g., transferred directly over the substrate). Suitable substrate materials and 2D materials are described elsewhere herein in greater detail.

[0031] In some embodiments, the 2D material is patterned, for example, as shown in the top portion of FIG. 1. In certain embodiments, for example, the 2D material comprises a plurality of holes extending through a bulk of the 2D material (e.g., from a first surface of the 2D material to a second surface of the 2D material that is substantially opposite the first surface). In certain embodiments, the plurality of holes may expose at least a portion of the substrate. In some embodiments, the plurality of holes are formed in the 2D material in a regular pattern or a random pattern. The plurality of holes may be formed by etching and / or lithography, in accordance with certain embodiments. In other embodiments, the 2D material is continuous, for example, as shown in the bottom portion of FIG. 1.

[0032] According to certain embodiments, referring to FIG. 1, the method comprises forming an InGaN buffer layer over the 2D material that is over the substrate. In some embodiments, the InGaN buffer layer is grown (e.g., epitaxially grown) over the 2D material that is over the substrate. In certain embodiments, for example, the InGaN buffer layer is grown (e.g., epitaxially grown) directly over the 2D material that is over the substrate. In certain embodiments wherein the 2D material comprises a plurality of holes, forming the InGaN buffer layer over the 2D material that is over the substrate comprises forming the InGaN buffer layer within at least a portion of the plurality of holes, for example, as shown in the top portion of FIG. 1. According to some embodiments wherein the 2D material comprises a plurality of holes, at least a portion of the InGaN buffer layer is directly grown (e.g., epitaxially grown) over the substrate.

[0033] According to some embodiments, forming the InGaN buffer layer over the 2D material that is over the substrate comprises growing the InGaN buffer layer by MBE or CVD (e.g., MOCVD).

[0034] In certain embodiments, without wishing to be bound by theory, the 2D material assisted growth (e.g., epitaxial growth) of the InGaN buffer layer results in the InGaN buffer layer having an advantageously high strain relaxation percentage, as described herein in greater detail. According to some embodiments, the 2D material assisted growth of the InGaN buffer layer may advantageously result in the InGaN buffer layer having a low dislocation density due to the high strain relaxation percentage. Suitable strain relaxation percentages and dislocation densities for the InGaN buffer layer are described herein in greater detail.

[0035] In some embodiments, as shown in FIG. 1, the method comprises forming a red-emitting InGaN layer over the InGaN buffer layer that is over the 2D material that is over the substrate. In certain embodiments, the red-emitting InGaN layer is grown (e.g., epitaxially grown) over the InGaN buffer layer that is over the 2D material that is over the substrate. For example, in certain embodiments, the red-emitting InGaN layer is grown (e.g., epitaxially grown) directly over the InGaN buffer layer that is over the 2D material that is over the substrate, thereby providing an article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the 2D material that is over the substrate.

[0036] In certain embodiments, forming the red-emitting InGaN layer over the InGaN buffer layer that is over the 2D material that is over the substrate comprises growing the red-emitting InGaN layer by MBE or CVD (e.g., MOCVD).

[0037] According to certain embodiments, forming the red-emitting InGaN layer over the InGaN buffer layer advantageously results in the red-emitting InGaN layer having a high strain relaxation percentage and / or a low dislocation density. In some embodiments, for example, the strain relaxation percentage and / or the dislocation density of the red-emitting InGaN layer may be substantially similar to the strain relaxation percentage and / or the dislocation density of the InGaN buffer layer (e.g., the strain relaxation percentage and / or the dislocation density of the red-emitting InGaN layer differs from the strain relaxation percentage and / or the dislocation density of the InGaN buffer layer by less than or equal to 10%, less than or equal to 5%, less than or equal to 1%, etc.).

[0038] In some embodiments, referring to FIG. 1, the method comprises separating the red- emitting InGaN layer and the InGaN buffer layer from the 2D material that is over the substrate. According to some embodiments, the substrate is a first substrate, and the method comprises transferring the red-emitting InGaN layer and the InGaN buffer layer to a second substrate, as shown in FIG. 1, thereby providing an article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the second substrate. Suitable second substrates are described elsewhere herein in greater detail.

[0039] FIG. 2 shows a process flow schematic diagram representing a method comprising separating a red-emitting InGaN layer and an InGaN buffer layer from a 2D material that is over a first substrate and transferring the red-emitting InGaN layer and the InGaN buffer layer from the 2D material that is over the first substrate to a second substrate, in accordance with certain embodiments. As shown in FIG. 2, a stressor layer may be deposited over a red-emitting InGaN layer that is over an InGaN buffer layer that is over a 2D material that is over a first substrate, in accordance with certain embodiments. In some embodiments, a handling layer is deposited over the stressor layer that is over the red-emitting InGaN layer that is over the InGaN buffer layer that is over the 2D material that is over the first substrate. In certain embodiments, the handling layer is a handling tape layer. The handling layer and the stressor layer may, in certain embodiments, facilitate the separation of the red-emitting InGaN layer and the InGaN buffer layer from the 2D material that is over the first substrate. In certain embodiments, the handling layer, the stressor layer, the red-emitting InGaN layer, and the InGaN buffer layer are separated from the 2D material that is over the first substrate. In some embodiments, the handling layer, the stressor layer, the red-emitting InGaN layer, and the InGaN buffer layer are transferred to a second substrate. In some embodiments, the handling layer and the stressor layer are separated from the red-emitting InGaN layer that is over the InGaN buffer layer that is over the second substrate, thereby providing an article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the second substrate.

[0040] According to certain embodiments, an article is described. FIG. 3 shows a schematic diagram of an article comprising a red-emitting InGaN layer that is over an InGaN buffer layer that is over a 2D material that is over a substrate, in accordance with certain embodiments.

[0041] In certain embodiments, referring to FIG. 3, article 102a comprises substrate 110. The substrate may comprise any of a variety of suitable materials. In some embodiments, for example, the substrate comprises a Ill-nitride (e.g., gallium nitride (GaN) and / or aluminum nitride (AIN)), sapphire, silicon carbide (SiC) (e.g., 4H-SiC and / or 6H-SiC), and / or combinations thereof. Other substrate materials are also possible.

[0042] The substrate may have any of a variety of suitable thicknesses. Referring, for example, to FIG. 3, substrate 110 has thickness 302a. In some embodiments, the substrate has a thickness greater than or equal to 0.1 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 500 micrometers, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 1 centimeter, or greater. In certain embodiments, the substrate has a thickness less than or equal to 10 centimeters, less than or equal to 1 centimeter, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, less than or equal to 500 micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, or less than or equal to 0.5 micrometers. Combinations of the above recited ranges are possible (e.g., the substrate has a thickness greater than or equal to 0.1 micrometers and less than or equal to 10 centimeters). Other ranges are also possible. In certain embodiments, the substrate is advantageously thin.

[0043] According to certain embodiments, as shown in FIG. 3, article 102a comprises 2D material 108. In some embodiments, 2D material 108 is over substrate 110. In certain embodiments, 2D material 108 is directly over substrate 110. According to some embodiments, as shown in FIG. 3, 2D material 108 is continuous. In other embodiments, although not shown in FIG. 3, the 2D material is patterned (e.g., as described herein in reference to FIG. 1).

[0044] The 2D material may comprise any of a variety of suitable materials. According to some embodiments, the 2D material comprises an atomically thin material. In certain embodiments, for example, the 2D material comprises graphene, aBN, aGr, amorphous carbon, and / or a GBL. Other 2D materials are also possible.

[0045] In certain non-limiting embodiments, the substrate comprises a Ill-nitride (e.g., GaN, AIN) and / or sapphire and the 2D material comprises aBN. In some such embodiments, the 2D material comprising aBN may be grown (e.g., directly grown) on the substrate comprising the Ill-nitride and / or sapphire via MBE and / or MOCVD (see, for example, FIG. 6A, which shows a schematic diagram of a 2D material comprising aBN that is over a substrate comprising a III- nitride and / or sapphire, in accordance with certain embodiments). In other non-limiting embodiments, the substrate comprises a III- nitride (e.g., GaN, AIN) and / or sapphire and the 2D material comprises aGr. In some such embodiments, the 2D material comprising aGr may be grown (e.g., directly grown) on the substrate comprising the Ill-nitride and / or sapphire via MOCVD (see, for example, FIG. 6A, which shows a schematic diagram of a 2D material comprising aGr that is over a substrate comprising a Ill-nitride and / or sapphire, in accordance with certain embodiments). In yet other non-limiting embodiments, the substrate comprises SiC (e.g., 4H-SiC and / or 6H-SiC) and the 2D material comprises a GBL. In some such embodiments, the 2D material comprising the GBL may be grown on the substrate comprising SiC via a graphitization process (see, for example, FIG. 6B, which shows a schematic diagram of a 2D material comprising a GBL that is over a substrate comprising 4H-SiC, in accordance with certain embodiments). In certain embodiments, the graphitization process comprises a first graphitization step at a relatively high temperature (e.g., greater than or equal to 1600 °C) and ambient pressure under an atmosphere of inert gas (e.g., argon). In some embodiments, the graphitization process comprises a second graphitization step at a relatively low temperature (e.g., less than or equal to 1600 °C) and ambient pressure under an atmosphere of inert gas (e.g., argon). FIG. 7 shows a SEM image, Raman spectra, and a XPS spectrum of various 2D materials over various substrates, in accordance with certain embodiments. For example, the bottom right shows a SEM image of a 2D material comprising a GBL that is over a substrate comprising SiC, the top left shows a Raman spectrum of a 2D material comprising aGr, the bottom right shows a Raman spectrum of a 2D material comprising aBN, and the top right shows a XPS spectrum of a 2D material comprising aBN.

[0046] According to some embodiments, as shown in FIG. 3, article 102a comprises InGaN buffer layer 104. In some embodiments, InGaN buffer layer 104 is over 2D material 108 that is over substrate 110. In certain embodiments, InGaN buffer layer 104 is directly over 2D material 108 that is over (e.g., directly over) substrate 110.

[0047] The InGaN buffer layer may comprise indium in any of a variety of suitable amounts. In some embodiments, for example, the InGaN buffer layer comprises indium in an amount of less than 20 at%, less than or equal to 15 at%, less than or equal to 10 at%, or less than or equal to 5 at%. In certain embodiments, the InGaN buffer layer comprises indium in an amount of greater than or equal to 1 at%, greater than or equal to 5 at%, greater than or equal to 10 at%, or greater than or equal to 15 at%. Combinations of the above recited ranges are possible (e.g., the InGaN buffer layer comprises indium in an amount less than or equal to 20 at% and greater than or equal to 1 at%, the InGaN buffer layer comprises indium in an amount less than or equal to 10 at% and greater than or equal to 5 at%). Other ranges are also possible. In certain embodiments, the atomic percentage of indium in the InGaN buffer layer is determined by energy dispersive X- ray spectroscopy (EDS) and electron microscopy techniques such as SEM and / or transmission electron microscopy (TEM).

[0048] In certain embodiments, an indium content of the InGaN buffer layer is less than an indium content of the red-emitting InGaN layer. In some embodiments, the InGaN buffer layer comprises indium atoms in an amount that is at least 1 at% less, at least 5 at% less, at least 10 at% less, at least 15 at% less, or at least 20 at% less than the amount of indium atoms in the red- emitting InGaN layer. In certain embodiments, the InGaN buffer layer comprises indium atoms in an amount that is less than or equal to 30 at% less, less than or equal to 25 at% less, or less than or equal to 20 at% less than the amount of indium atoms in the red-emitting InGaN layer. Combinations of the above recited ranges are possible (e.g., the InGaN buffer layer comprises indium atoms in an amount that is at least 1 at% less and less than or equal to 30 at% less than the amount of indium atoms in the red-emitting InGaN layer). Other ranges are also possible.

[0049] In some embodiments, the concentration of indium atoms in the InGaN buffer layer is less than or equal to 0.99, less than or equal to 0.98, less than or equal to 0.97, less than or equal to 0.96, or less than or equal to 0.95 times the concentration of indium atoms in the red-emitting InGaN layer. In certain embodiments, the concentration of indium atoms in the InGaN buffer layer is at least 0.1, at least 0.2, at least 0.3, at least 0.4, or at least 0.5 times the concentration of indium atoms in the red-emitting InGaN layer. Combinations of the above recited ranges are possible (e.g., the concentration of indium atoms in the InGaN buffer layer is less than or equal to 0.99 and at least 0.1 times the concentration of indium atoms in the red-emitting InGaN layer). Other ranges are also possible.

[0050] The InGaN buffer layer may have any of a variety of suitable strain relaxation percentages. In some embodiments, the InGaN buffer layer has an advantageously high strain relaxation percentage due to the 2D material assisted growth (e.g., epitaxial growth) of the InGaN buffer layer. In some embodiments, for example, the InGaN buffer layer has a strain relaxation greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, or greater than or equal to 95%. In certain embodiments, the InGaN buffer layer has a strain relaxation less than or equal to 100%, less than or equal to 95%, less than or equal to 90%, or less than or equal to 85%. Combinations of the above recited ranges are possible (e.g., the InGaN buffer layer has strain relaxation greater than or equal to 80% and less than or equal to 100%, the InGaN buffer layer has a strain relaxation greater than or equal to 90% and less than or equal to 95%). Other ranges are also possible. In certain embodiments, the strain relaxation percentage of the InGaN buffer layer is determined by reciprocal space mapping using X-ray diffraction (XRD). For example, the position of a reciprocal lattice point of the InGaN buffer layer is measured in reciprocal space relative to a reciprocal lattice point of a substrate that the InGaN buffer layer is formed on (assuming unstrained formation), and the percent strain relaxation of the InGaN buffer layer is quantitatively determined based on the relative position of the reciprocal lattice point of the InGaN buffer layer. See, for example, FIGS. 8B-10. FIG. 8A shows, in accordance with certain embodiments, a SEM image of a surface of an InGaN buffer layer formed over a 2D material that is over a substrate. FIGS. 8B-8C show, in accordance with certain embodiments, a comparison of reciprocal spacing mapping images of an InGaN buffer layer formed: (i) over a substrate (FIG. 8B); and (ii) over a 2D material that is over a substrate (FIG. 8C). FIG. 9 shows an enlarged and annotated version of the reciprocal spacing mapping image of the InGaN buffer layer formed over the 2D material that is over the substrate shown in FIG. 8C, in accordance with certain embodiments. FIG. 10 shows a reciprocal spacing mapping image of an InGaN buffer layer formed over a 2D material that is over a substrate, showing an InGaN buffer layer with a strain relaxation of 88%.

[0051] The InGaN buffer layer may have any of a variety of suitable dislocation densities. In some embodiments, the high strain relaxation percentage can lead to relatively low dislocation densities within the InGaN buffer layer. In certain embodiments, 2D material assisted growth of the InGaN buffer layer may also lead to relatively low dislocation densities within the InGaN buffer layer. In certain embodiments, the InGaN buffer layer has an advantageously low number of defects such as edge dislocations, screw dislocations, threading dislocations, and / or anti-phase boundaries.

[0052] In certain embodiments, the InGaN buffer layer has a dislocation density less than or equal to 109cm'2, less than or equal to 108cm'2, less than or equal to 107cm'2, less than or equal to 106cm'2, less than or equal to 105cm'2, less than or equal to 104cm'2, less than or equal to 103cm'2, less than or equal to 102cm'2, or less than or equal to 10 cm'2. In some embodiments, the InGaN buffer layer has a dislocation density greater than or equal to 1 cm'2, greater than or equal to 10 cm'2, greater than or equal to 102cm'2, greater than or equal to 103cm'2, greater than or equal to 104cm'2, greater than or equal to 105cm'2, greater than or equal to 106cm'2, greater than or equal to 107cm'2, or greater than or equal to 108cm'2. Combinations of the above recited ranges are possible (e.g., the InGaN buffer layer has a dislocation density less than or equal to 109cm'2and greater than or equal to 1 cm'2). Other ranges are also possible. In certain embodiments, the dislocation density of the InGaN buffer layer is measured by X-ray diffraction techniques, Electron Channeling Contrast Imaging (ECO) from scanning electron microscopy (SEM), and / or transmission electron microscopy (TEM).

[0053] The InGaN buffer layer may have any of a variety of suitable thicknesses. Referring, for example, to FIG. 3, InGaN buffer layer 104 has thickness 302b. In some embodiments, the InGaN buffer layer has a thickness greater than or equal to 0.01 micrometers, greater than or equal to 0.02 micrometers, greater than or equal to 0.05 micrometers, greater than or equal to 0.1 micrometers, greater than or equal to 0.2 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 20 micrometers, greater than or equal to 50 micrometers, or greater. In certain embodiments, the InGaN buffer layer has a thickness less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 20 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, less than or equal to 0.5 micrometers, less than or equal to 0.2 micrometers, less than or equal to 0.1 micrometers, less than or equal to 0.05 micrometers, less than or equal to 0.02 micrometers, or less. Combinations of the above recited ranges are possible (e.g., the InGaN buffer layer has a thickness greater than or equal to 0.01 micrometers and less than or equal to 100 micrometers). Other ranges are also possible. In certain embodiments, the InGaN buffer layer is advantageously thin.

[0054] In certain embodiments, as shown in FIG. 3, article 102a comprises red-emitting InGaN layer 106. In some embodiments, red-emitting InGaN layer 106 is over InGaN buffer layer 104 that is over 2D material 108 that is over substrate 110. In some embodiments, red-emitting InGaN layer 106 is directly over InGaN buffer layer 104 that is over (e.g., directly over) 2D material 108 that is over (e.g., directly over) substrate 110.

[0055] According to certain embodiments, the red-emitting InGaN layer and the substrate are lattice mismatched. For example, in some embodiments, the red-emitting InGaN layer and the substrate have a percent lattice mismatch greater than or equal to 0.1%, greater than or equal to 1%, greater than or equal to 2%, greater than or equal to 3%, greater than or equal to 4%, greater than or equal to 5%, greater than or equal to 6%, or greater than or equal to 7%. In certain embodiments, the red-emitting InGaN layer and the substrate have a percent lattice mismatch less than or equal to 8%, less than or equal to 7%, less than or equal to 6%, less than or equal to 5%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, or less than or equal to 1%. Combinations of the above recited ranges are possible (e.g., the red-emitting InGaN layer and the substrate have a percent lattice mismatch greater than or equal to 0.1% and less than or equal to 8%, the red-emitting InGaN layer and the substrate have a percent lattice mismatch greater than or equal to 4% and less than or equal to 5%). Other ranges are also possible. In some embodiments, the percent lattice mismatch between the red-emitting InGaN layer and the substrate is determined by XRD.

[0056] According to certain non-limiting embodiments wherein the substrate comprises GaN and / or sapphire, the percent lattice mismatch between the red-emitting InGaN layer and the substrate is greater than or equal to 0.1% and less than or equal to 5%. In some other nonlimiting embodiments wherein the substrate comprises AIN and / or sapphire, the percent lattice mismatch between the red-emitting InGaN layer and the substrate is greater than or equal to 2% and less than or equal to 8%. In yet other non-limiting embodiments wherein the substrate comprises SiC (e.g., 4H-SiC and / or 6H-SiC), the percent lattice mismatch between the red- emitting InGaN layer and the substrate is greater than or equal to 2% and less than or equal to 8%.

[0057] The red-emitting InGaN layer may comprise indium in any of a variety of suitable amounts. According to some embodiments, the red-emitting InGaN layer comprises an atomic percentage of indium that advantageously allows the red-emitting InGaN layer to emit red light. In certain embodiments, for example, the red-emitting InGaN layer comprises indium in an amount greater than or equal to 20 at%, greater than or equal to 25 at%, greater than or equal to 30 at%, or greater than or equal to 35 at%. In some embodiments, the red-emitting InGaN layer comprises indium in an amount less than or equal to 40 at%, less than or equal to 35 at%, less than or equal to 30 at%, or less than or equal to 25 at%. Combinations of the above recited ranges are possible (e.g., the red-emitting InGaN layer comprises indium in an amount greater than or equal to 20 at% and less than or equal to 40 at%, the red-emitting InGaN layer comprises indium in an amount greater than or equal to 30 at% and less than or equal to 35 at%). Other ranges are also possible. In some embodiments, the atomic percentage of indium in the red- emitting InGaN layer is determined by EDS and electron microscopy techniques such as SEM and / or TEM.

[0058] According to some embodiments, the red-emitting InGaN layer (e.g., comprising indium in an amount greater than or equal to 20 at% and less than or equal to 40 at%) advantageously does not exhibit phase separation. For example, in some embodiments, the red-emitting InGaN layer does not form clusters and / or regions of In and / or Ga within the red-emitting InGaN layer.

[0059] According to certain embodiments, an indium content of the red-emitting InGaN layer is greater than an indium content of the InGaN buffer layer. In some embodiments, the red- emitting InGaN layer comprises indium atoms in an amount that is at least 1 at% greater, at least 5 at% greater, at least 10 at% greater, at least 15 at% greater, or at least 20 at% greater than the amount of indium atoms in the InGaN buffer layer. In some embodiments, the InGaN red- emitting layer comprises indium atoms in an amount less than or equal to 40 at% greater, less than or equal to 30 at% greater, less than or equal to 25 at% greater, or less than or equal to 20 at.% greater than the amount of indium atoms in the InGaN buffer layer. Combinations of the above recited ranges are possible (e.g., the red-emitting InGaN layer comprises indium atoms in an amount that is at least 1 at% greater and less than or equal to 40 at% greater than the amount of indium atoms in the InGaN buffer layer). Other ranges are also possible.

[0060] In some embodiments, the concentration of indium atoms in the red-emitting InGaN layer is at least 1.1, at least 2, at least 3, at least 4, or at least 5 times the concentration of indium atoms in the InGaN buffer layer. In certain embodiments, the concentration of indium atoms in the red-emitting InGaN layer is less than or equal to 20, less than or equal to 15, or less than or equal to 10 times the concentration of indium atoms in the InGaN buffer layer. Combinations of the above recited ranges are possible (e.g., the concentration of indium atoms in the red-emitting InGaN layer is at least 1.1 and less than or equal to 20 times the concentration of indium atoms in the InGaN buffer layer). Other ranges are also possible.

[0061] As described herein in greater detail, the red-emitting InGaN layer may have an advantageously high strain relaxation percentage, in accordance with certain embodiments. For example, in some embodiments, the red-emitting InGaN layer has a strain relaxation percentage that is substantially similar to the strain relaxation percentage of the InGaN buffer layer. In certain embodiments, the strain relaxation percentage of the red-emitting InGaN layer differs from the strain relaxation percentage of the InGaN buffer layer by less than or equal to 10%, less than or equal to 5%, less than or equal to 1%, or less). In some embodiments, the red-emitting InGaN layer has a strain relaxation percentage greater than or equal to 80% and less than or equal to 100%.

[0062] In some embodiments, the red-emitting InGaN layer may have an advantageously low dislocation density, as described herein in greater detail. In certain embodiments, for example, the red-emitting InGaN layer has a dislocation density that is substantially similar to the dislocation density of the InGaN buffer layer. In certain embodiments, the dislocation density of the red-emitting InGaN layer differs from the dislocation density of the InGaN buffer layer by less than or equal to 10%, less than or equal to 5%, less than or equal to 1%, or less). In some embodiments, the red-emitting InGaN layer has a dislocation density less than or equal to 109cm'2and greater than or equal to 1 cm'2. According to some embodiments, the red-emitting InGaN layer is configured to emit electromagnetic radiation. In certain embodiments, for example, the red-emitting InGaN layer is configured to emit light at a wavelength corresponding to red light.

[0063] The red-emitting InGaN layer may be configured to emit electromagnetic radiation at any of a variety of suitable wavelengths. In some embodiments, for example, the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength greater than or equal to 620 nm, greater than or equal to 630 nm, greater than or equal to 640 nm, greater than or equal to 650 nm, or greater than or equal to 660 nm. In certain embodiments, the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength less than or equal to 670 nm, less than or equal to 660 nm, less than or equal to 650 nm, less than or equal to 640 nm, or less than or equal to 630 nm. Combinations of the above recited ranges are possible (e.g., the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength greater than or equal to 620 nm and less than or equal to 670 nm, the red-emitting InGaN layer is configured to emit electromagnetic radiation a wavelength greater than or equal to 640 nm and less than or equal to 650 nm). Other ranges are also possible.

[0064] The red-emitting InGaN layer may have any of a variety of suitable thicknesses. Referring, for example, to FIG. 3, red-emitting InGaN layer 106 has thickness 302c. In some embodiments, the red-emitting InGaN layer has a thickness greater than or equal to 0.1 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 500 micrometers, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 1 centimeter, or greater. In certain embodiments, the red-emitting InGaN layer has a thickness less than or equal to 10 centimeters, less than or equal to 1 centimeter, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, less than or equal to 500 micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, or less than or equal to 0.5 micrometers. Combinations of the above recited ranges are possible (e.g., the red-emitting InGaN layer has a thickness greater than or equal to 0.1 micrometers and less than or equal to 10 centimeters). Other ranges are also possible. In certain embodiments, the red-emitting InGaN layer is advantageously thin. In certain embodiments, the red-emitting InGaN layer is or comprises a LED layer (e.g., a micro-LED layer). In some embodiments, the LED layer is a multiple quantum well (MQW)- based LED layer (e.g., a MQW-based micro-LED layer).

[0065] The article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the 2D material that is over the substrate may have any of a variety of suitable thicknesses. For example, referring to FIG. 3, article 102a has thickness 302e. In certain embodiments, the article (e.g., article 102a) has a thickness greater than 0.2 micrometers, greater than or equal to 0.3 micrometers, greater than or equal to 0.4 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 20 micrometers, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 200 micrometers, greater than or equal to 500 micrometers, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 1 centimeter, greater than or equal to 2 centimeters, greater than or equal to 5 centimeters, greater than or equal to 10 centimeters, greater than or equal to 20 centimeters, or greater. In some embodiments, the article (e.g., article 102a) has a thickness less than 21 centimeters, less than or equal to 20 centimeters, less than or equal to 10 centimeters, less than or equal to 5 centimeters, less than or equal to 2 centimeters, less than or equal to 1 centimeter, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, less than or equal to 500 micrometers, less than or equal to 200 micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 20 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, less than or equal to 0.5 micrometers, less than or equal to 0.4 micrometers, less than or equal to 0.3 micrometers, or less. Combinations of the above recited ranges are possible (e.g., the article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the 2D material that is over the substrate has a thickness greater than 0.2 micrometers and less than 21 centimeters). Other ranges are also possible.

[0066] As described herein in greater detail, the red-emitting InGaN layer and the InGaN buffer layer may be separated from the 2D material that is over the substrate (e.g., as described herein in reference to FIGS. 1-2). FIG. 4 shows a schematic diagram of an article comprising a red- emitting InGaN layer that is over an InGaN buffer layer, in accordance with certain embodiments. In some embodiments, as shown in FIG. 4, article 102b comprises InGaN buffer layer

[0067] 104.

[0068] The InGaN buffer layer may comprise indium in any of a variety of suitable amounts (e.g., the InGaN buffer layer comprises indium in an amount less than or equal to 20 at% and greater than or equal to 1 at%), as described herein in greater detail with respect to FIG. 3. The InGaN buffer layer may have any of a variety of suitable strain relaxation percentages possible (e.g., the InGaN buffer layer has strain relaxation greater than or equal to 80% and less than or equal to 100%), as described herein in greater detail with respect to FIG. 3. The InGaN buffer layer may have any of a variety of suitable dislocation densities (e.g., less than or equal to 109cm'2and greater than or equal to 1 cm'2), as described herein in greater detail with respect to FIG. 3. The InGaN buffer layer may have any of a variety of suitable thicknesses (e.g., thickness 302b), as described herein in greater detail with respect to FIG. 3.

[0069] In certain embodiments, referring to FIG. 4, article 102b comprises red-emitting InGaN layer 106. In some embodiments, red-emitting InGaN layer 106 is over InGaN buffer layer 104. In certain embodiments, red-emitting InGaN layer 106 is directly over InGaN buffer layer 104.

[0070] The red-emitting InGaN layer may comprise indium in any of a variety of suitable amounts (e.g., the red-emitting InGaN layer comprises indium in an amount greater than or equal to 20 at% and less than or equal to 40 at%), as described herein in greater detail with respect to FIG. 3. The red-emitting InGaN layer may be configured to emit electromagnetic radiation at any of a variety of suitable wavelengths (e.g., the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength greater than or equal to 620 nm and less than or equal to 670 nm), as described herein in greater detail with respect to FIG. 3. The red-emitting InGaN layer may have any of a variety of suitable thicknesses (e.g., thickness 302c), as described herein in greater detail with respect to FIG. 3).

[0071] The article comprising the red-emitting InGaN layer that is over the InGaN buffer layer may have any of a variety of suitable thicknesses. For example, referring to FIG. 4, article 102b has thickness 302f. In certain embodiments, the article (e.g., article 102b) has a thickness greater than 0.1 micrometers, greater than or equal to 0.2 micrometers, greater than or equal to 0.3 micrometers, greater than or equal to 0.4 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 20 micrometers, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 200 micrometers, greater than or equal to 500 micrometers, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 1 centimeter, greater than or equal to 2 centimeters, greater than or equal to 5 centimeters, greater than or equal to 10 centimeters, or greater. In some embodiments, the article (e.g., article 102b) has a thickness less than 11 centimeters, less than or equal to 10 centimeters, less than or equal to 5 centimeters, less than or equal to 2 centimeters, less than or equal to 1 centimeter, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, less than or equal to 500 micrometers, less than or equal to 200 micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 20 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, less than or equal to 0.5 micrometers, less than or equal to 0.4 micrometers, less than or equal to 0.3 micrometers, less than or equal to 0.2 micrometers, or less. Combinations of the above recited ranges are possible (e.g., the red-emitting InGaN layer that is over the InGaN buffer layer has a thickness greater than 0.1 micrometers and less than 11 centimeters). Other ranges are also possible.

[0072] As described herein in greater detail, the red-emitting InGaN layer and the InGaN buffer layer may be transferred to a second substrate (e.g., as described herein in reference to FIGS. 1- 2). FIG. 5 shows a schematic diagram of an article comprising a red-emitting InGaN layer that is over an InGaN buffer layer that is over a second substrate, in accordance with certain embodiments.

[0073] According to some embodiments, referring to FIG. 5, article 102c comprises second substrate 112. The second substrate may comprise any of a variety of suitable materials. In certain embodiments, for example, the second substrate comprises silicon (Si), silicon dioxide (SiO2), glass, quartz, a complementary metal-oxide- silicon (CMOS) backplane, an oxide thin film transistor (TFT) backplane, and / or combinations thereof. Other materials for the second substrate are also possible.

[0074] The second substrate may have any of a variety of suitable thicknesses. Referring, for example, to FIG. 5, second substrate 112 has thickness 302d. In some embodiments, the second substrate has a thickness greater than or equal to 0.1 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 500 micrometers, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 1 centimeter, or greater. In certain embodiments, the second substrate has a thickness less than or equal to 10 centimeters, less than or equal to 1 centimeter, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, less than or equal to 500 micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, or less than or equal to 0.5 micrometers. Combinations of the above recited ranges are possible (e.g., the second substrate has a thickness greater than or equal to 0.1 micrometers and less than or equal to 10 centimeters). Other ranges are also possible. In certain embodiments, the second substrate is advantageously thin.

[0075] In certain embodiments, article 102c comprises InGaN buffer layer 104. In some embodiments, InGaN buffer layer 104 is over second substrate 112. In certain embodiments, InGaN buffer layer 104 is directly over second substrate 112.

[0076] The InGaN buffer layer may comprise indium in any of a variety of suitable amounts (e.g., the InGaN buffer layer comprises indium in an amount less than or equal to 20 at% and greater than or equal to 1 at%), as described herein in greater detail with respect to FIG. 3. The InGaN buffer layer may have any of a variety of suitable strain relaxation percentages possible (e.g., the InGaN buffer layer has strain relaxation greater than or equal to 80% and less than or equal to 100%), as described herein in greater detail with respect to FIG. 3. The InGaN buffer layer may have any of a variety of suitable dislocation densities (e.g., less than or equal to 109cm'2and greater than or equal to 1 cm'2), as described herein in greater detail with respect to FIG. 3. The InGaN buffer layer may have any of a variety of suitable thicknesses (e.g., thickness 302b), as described herein in greater detail with respect to FIG. 3).

[0077] In certain embodiments, article 102c comprises red-emitting InGaN layer 106. In some embodiments, red-emitting InGaN layer 106 is over InGaN buffer layer 104 that is over second substrate 112. According to certain embodiments, red-emitting InGaN layer 106 is directly over InGaN buffer layer 104 that is over (e.g., directly over) second substrate 112.

[0078] The red-emitting InGaN layer may comprise indium in any of a variety of suitable amounts (e.g., the red-emitting InGaN layer comprises indium in an amount greater than or equal to 20 at% and less than or equal to 40 at%), as described herein in greater detail with respect to FIG. 3. The red-emitting InGaN layer may be configured to emit electromagnetic radiation at any of a variety of suitable wavelengths (e.g., the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength greater than or equal to 620 nm and less than or equal to 670 nm), as described herein in greater detail with respect to FIG. 3. The red-emitting InGaN layer may have any of a variety of suitable thicknesses (e.g., thickness 302c), as described herein in greater detail with respect to FIG. 3). The article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the second substrate may have any of a variety of suitable thicknesses. For example, referring to FIG. 5, article 102c has thickness 302g. In certain embodiments, the article (e.g., article 102c) has a thickness greater than 0.2 micrometers, greater than or equal to 0.3 micrometers, greater than or equal to 0.4 micrometers, greater than or equal to 0.5 micrometers, greater than or equal to 1 micrometer, greater than or equal to 2 micrometers, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 20 micrometers, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 200 micrometers, greater than or equal to 500 micrometers, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 1 centimeter, greater than or equal to 2 centimeters, greater than or equal to 5 centimeters, greater than or equal to 10 centimeters, greater than or equal to 20 centimeters, or greater. In some embodiments, the article (e.g., article 102c) has a thickness less than 21 centimeters, less than or equal to 20 centimeters, less than or equal to 10 centimeters, less than or equal to 5 centimeters, less than or equal to 2 centimeters, less than or equal to 1 centimeter, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, less than or equal to 500 micrometers, less than or equal to 200 micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 20 micrometers, less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 2 micrometers, less than or equal to 1 micrometer, less than or equal to 0.5 micrometers, less than or equal to 0.4 micrometers, less than or equal to 0.3 micrometers, or less. Combinations of the above recited ranges are possible (e.g., the article comprising the red-emitting InGaN layer that is over the InGaN buffer layer that is over the second substrate has a thickness greater than 0.2 micrometers and less than 21 centimeters). Other ranges are also possible.

[0079] According to certain embodiments, a device and / or system is described. In certain embodiments, the device and / or system comprises a red-emitting layer that is over an InGaN buffer layer. In some embodiments, for example, the device and / or system comprises article 102b shown in FIG. 4. In other embodiments, the device and / or system comprises a red- emitting layer that is over an InGaN buffer layer that is over a second substrate. For example, in some embodiments, the device and / or system comprises article 102c shown in FIG. 5. In certain embodiments, the device and / or system is or comprises a LED stack (e.g., a micro-LED stack) comprising one or more LEDs (e.g., micro-LEDs) configured to emit light at a wavelength corresponding to light in the ultraviolet (UV) and / or visible electromagnetic spectrum. In some embodiments, the device and / or system is or comprises a multicolor LED stack comprising at least two LEDs, each LED configured to emit light at a distinct wavelength corresponding to light in the UV and / or visible electromagnetic spectrum. In certain embodiments, the device and / or system is or comprises a full color LED stack comprising a plurality of LEDs (i.e., at least two LEDs), the stack being configured to emit light at a first wavelength corresponding to red light, a second wavelength corresponding to green light, and a third wavelength corresponding to blue light (e.g., a RGB LED stack).

[0080] The term “ultraviolet electromagnetic spectrum”, as used herein, refers to electromagnetic radiation having a wavelength of from 100 nm to below 380 nm. The term “visible electromagnetic spectrum” is used herein to describe electromagnetic radiation having a wavelength of from 380 nm to 750 nm. “Blue light,” as used herein, refers to electromagnetic radiation having a wavelength of from 450 nm to less than 495 nm. As used herein, “green light” refers to electromagnetic radiation having a wavelength of from 495 nm to 570 nm.

[0081] When a structure (e.g., layer and / or device) is referred to as being “on,” “over,” or “overlying” another structure (e.g., layer or substrate), it is over at least a portion of that structure. In some cases, a structure that is referred to as being “on,” “over,” or “overlying” another structure is over the entirety of that structure. When a structure (e.g., layer and / or device) is referred to as being “on,” “over,” or “overlying” another structure (e.g., layer or substrate), it can be directly on the structure, or an intervening structure (e.g., a layer, air gap) also may be present. A structure that is “directly on,” “directly over,” or “in direct contact with” another structure means that no intervening structure is present.

[0082] U.S. Provisional Patent Application No. 63 / 683,151, filed August 14, 2024, and entitled “TWO-DIMENSIONAL MATERIAL ASSISTED EPITAXY OF RED LIGHT EMITTERS,” is incorporated herein by reference in its entirety for all purposes.

[0083] While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present invention.

[0084] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0085] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0086] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0087] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0088] As used herein, “wt%” is an abbreviation of weight percentage. As used herein, “at%” is an abbreviation of atomic percentage.

[0089] Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

[0090] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0091] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: forming a red-emitting InGaN layer over an InGaN buffer layer that is over a two-dimensional (2D) material that is over a substrate, wherein: the red-emitting InGaN layer and the substrate have a percent lattice mismatch of at least 0.1%, and an indium content of the red-emitting InGaN layer is greater than an indium content of the InGaN buffer layer.

2. The method of claim 1, further comprising forming the InGaN buffer layer over the 2D material that is over the substrate.

3. The method of any one of claims 1-2, further comprising separating the red- emitting InGaN layer and the InGaN buffer layer from the 2D material that is over the substrate.

4. The method of any one of claims 1-3, wherein the substrate is a first substrate, and further comprising transferring the red-emitting InGaN layer and the InGaN buffer layer to a second substrate.

5. The method of any one of claims 1-4, wherein the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength greater than or equal to 620 nm and less than or equal to 670 nm.

6. The method of any one of claims 1-5, wherein the red-emitting InGaN layer comprises indium in an amount greater than or equal to 20 atomic percent (at%).

7. The method of any one of claims 1-6, wherein the InGaN buffer layer comprises indium in an amount less than 20 at%.

8. The method of any one of claims 1-7, wherein the 2D material comprises graphene, amorphous boron nitride (aBN), amorphous graphene (aGr), amorphous carbon, and / or a graphene buffer layer (GBL).

9. The method of any one of claims 1-8, wherein the substrate comprises GaN, AIN, sapphire, 4H-SiC, and / or 6H-SiC.

10. The method of any one of claims 1-9, wherein forming the red-emitting InGaN layer over the InGaN buffer layer that is over the 2D material that is over the substrate comprises growing the red-emitting InGaN layer by molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD).

11. The method of any one of claims 1-10, wherein the red-emitting InGaN layer and the substrate have a percent lattice mismatch of less than or equal to 8%.

12. An article, comprising: an InGaN buffer layer; and a red-emitting InGaN layer over the InGaN buffer layer, wherein the InGaN buffer layer has a strain relaxation greater than or equal to 80%.

13. The article of claim 12, further comprising a 2D material that is over a first substrate, wherein the InGaN buffer layer is over the 2D material.

14. The article of claim 12, further comprising a second substrate, wherein the InGaN buffer layer is over the second substrate.

15. The article of any one of claims 12-14, wherein the red-emitting InGaN layer comprises indium in an amount greater than or equal to 20 at%.

16. The article of any one of claims 12-15, wherein the InGaN buffer layer comprises indium in an amount less than 20 at%.

17. The article of any one of claims 12-16, wherein the red-emitting InGaN layer is configured to emit electromagnetic radiation at a wavelength greater than or equal to 620 nm and less than or equal to 670 nm.

Images