NANOWIRE-BASED OPTOELECTRONIC DEVICE WITH TRANSITION ZONES

Description

TECHNICAL FIELD

[0001] The present invention relates in particular to the field of microelectronics and optoelectronics technologies. It finds a particularly advantageous, but not limiting, application in LED-based display systems (from the English “Light-Emitting Diode”). STATE OF THE ART

[0002] Documents WO 2014 / 154880 A1, WO 2022 / 069431 A1, and WO 2022 / 002896 A1 are part of the technological background relating to the present invention.

[0003] A display screen generally comprises a plurality of pixels arranged on a so-called basal plane and emitting independently of one another. Each color pixel generally comprises at least three components for emitting and / or converting a luminous flux, also called sub-pixels. These sub-pixels each emit a luminous flux in substantially a single color (typically red, green and blue). The color of a pixel perceived by an observer comes from the superposition of the different luminous fluxes emitted by the sub-pixels.

[0004] Typically, an LED or micro-LED is used to emit the light flux associated with a sub-pixel. An LED may in particular comprise a plurality of active nanowires arranged in a periodic photonic crystal and emitting said light flux at the desired wavelength. This photonic crystal is characterized in particular by the diameter of the nanowires and the pitch between the nanowires.

[0005] There Figure 4aillustrates a typical arrangement of subpixels within a pixel. In practice, however, this type of arrangement does not provide optimal performance. There is therefore a need to improve the performance of nanowire-based self-emissive pixels. SUMMARY

[0006] To achieve this objective, according to the present invention, an optoelectronic device is provided according to independent claim 1 in the appendix, comprising at least: a first LED extending mainly in a plane defined by a first direction and a second direction, said first LED comprising a plurality of first nanowires having first diameters having a value substantially equal to a first target value ϕ 10 and organized in N LED,x,1 rows oriented in the second direction, called first rows, said first rows being separated by first distances taken in the first direction having a value substantially equal to a first target distance P 10,x , said first LED being configured to emit a first light beam having mainly a first wavelength λ 1 , and a first transition zone extending mainly in the plane and at least partly bordering said first LED, said first transition zone comprising a plurality of first transition nanowires having first transition diameters and organized in N trans,x,1 rows oriented in the second direction, called first transition rows and indexed according to a numbering from 1 to N trans,x,1 moving away from the first LED in the first direction, the first rows being indexed according to a numbering from 1 to N LED,x,1 in the first direction moving closer to the first transition zone, , the device being characterized in that the first transition zone comprises a first transition sub-zone formed by the N sub-trans,1 first transition rows, with 2 ≤ N sub-trans,1 ≤ N trans,x,1 , bordering the first LED, first transition sub-zone in which: the first transition nanowires are such that: i. the value of the first transition diameters of the first transition nanowires of the first transition row No. 1 varies in a proportion less than 5% of the first target value ϕ 10 , and ii. the value of the first transition diameter of each first transition nanowire of any first transition row No. i, i being between 2 and N sub-trans,1 , varies in a proportion between 3% and 13% of the value of the first transition diameter of the first transition nanowire of the first transition row No. i-1 being closest to it, and / or the first transition nanowires are such that: i.the first row n°N LED,x,1 and the first transition row n°1 being separated in the first direction x by a first interface distance d interface,1, the first interface distance d interface,1 and the distance in the first direction between the first transition row n°1 and the first transition row n°2 vary in a proportion comprised between 2% and 4% of the distance in the first direction between the first row n°N LED,x,1 -1 and the first row n°N LED,x,1 and the first interface distance d interface,1 respectively, and ii. the distance in the first direction between any first transition row n°i and the first transition row n°i+1 varies in a proportion comprised between 2% and 4% of the distance in the first direction between the first transition row n°i-1 and the first transition row n°i, i being comprised between 2 and N sub-trans,1 -1.

[0007] Advantageous embodiments of the optoelectronic device according to the present invention are the subject of the appended dependent claims.

[0008] The optoelectronic device may also be described as comprising at least: a first LED comprising a plurality of first nanowires having first diameters having a value substantially equal to a first target diameter value ϕ 10 and organized in rows oriented in a second direction, called first rows, and separated by first distances taken in a first direction having a value substantially equal to a first target distance value p 10,x , said first LED being configured to emit a first light beam having mainly a first wavelength λ1, and a first transition zone at least partly bordering said first LED, and comprising a plurality of first transition nanowires having first transition diameters and organized in rows oriented in the second direction, called first transition rows, and separated by first transition distances in the first direction, said first LED and said first transition zone being separated, between a first row and a first adjacent transition row, by a first interface distance in the first direction, the device being characterized in that, moving away from the first LED in the first direction: the value of the first transition diameters of the first transition row adjacent to the first LED varies in a proportion of less than 5% of the first target diameter value, and the value of the first transition diameters varies from one to another, between two adjacent first transition rows, in a proportion of between 3% and 13%, and / or the value of the first interface distance is between 2% and 4% of the first target distance value, the value of the distance between the first transition row adjacent to the first LED and the first transition row adjacent thereto is between 2% and 4% of the first interface distance, and the value of the first transition distances varies from one to another, between two adjacent first transition rows, in a proportion of between 2% and 4%.

[0009] An important issue in these technologies concerns the transition zones between adjacent sub-pixels. Indeed, the sub-pixels constituting current display screens are typically placed next to each other, while a sub-pixel very often has a different nanowire diameter and pitch between nanowires than the neighboring sub-pixel. Only abrupt transition zones 1000' separate the sub-pixels, as shown in Figure 4a The same applies at the upper level, between pixels. The presence of these abrupt 1000' transition zones has the disadvantage of breaking the symmetry of the network and, consequently, of creating detrimental edge effects during the growth of the nanowires. These edge effects also prevent the achievement of an optical cavity effect at the level of each sub-pixel, which is nevertheless advantageous.

[0010] The presence of a transition zone makes it possible to avoid any break in symmetry and to reduce the phenomenon of edge effects.

[0011] According to an advantageous possibility, the transition nanowires also make it possible to extend the gamut of a set of sub-pixels, that is to say the set of colors that it can render. The spectrum of colors that can be emitted by a pixel is in fact typically limited to the set of colors included in the triangle defined by the native colors emitted by three sub-pixels constituting said pixel on the chromaticity diagram of the CIE (International Commission on Illumination) XYZ colorimetric system, typically red (C 1 ), green (C 2 ) and blue (C 3 ), as represented in Figure 6a The colors included in this triangle, called gamut 4, are actually obtained by linear combinations of the three native colors emitted by the three sub-pixels of the pixel. Only a reduced range of chromaticities can thus be obtained. The present invention proposes a solution to extend this range.

[0012] Thus, in this regard, it is expected that the first transition nanowires have an active region configured to emit a first transition light beam having mainly a first transition wavelength distinct from the first wavelength λ1. BRIEF DESCRIPTION OF THE FIGURES

[0013] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which: There figure 1 represents a top view of the device according to an embodiment of the invention, comprising an LED and a transition zone. The figure 2 represents a top view of the device according to an embodiment of the invention, comprising two LEDs separated by a transition zone. The figure 3represents a cross-section of the device according to one embodiment of the invention, comprising two LEDs separated by a transition zone. The Figure 4a represents a four-LED device having abrupt transition zones between the LEDs, according to the prior art. The Figure 4b represents a device with four LEDs according to an embodiment of the invention, this device having progressive transition zones between the LEDs. The Figure 5 represents a device according to the invention with three LEDs separated by progressive transition zones. The Figure 6a represents the chromaticity diagram of a pixel commonly used in current display screens. The Figure 6b represents the chromaticity diagram of a pixel that can be obtained using the device that is the subject of the invention. The figure 7represents a three-LED device according to one embodiment of the invention, this device having active progressive transition zones between the LEDs as well as an intermediate region emitting white light. The figure 8 represents a device according to the invention with two LEDs separated by a progressive transition zone.

[0014] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. In particular, the dimensions of each of the elements are not representative of reality. DETAILED DESCRIPTION

[0015] Before beginning a detailed review of embodiments of the invention, optional characteristics which may possibly be used in combination or alternatively are set out below: According to one embodiment, the first transition diameters of the first transition nanowires of the same first transition row are equal.

[0016] According to one embodiment: the value of the first transition diameters of the first transition nanowires of the first transition rows exhibits a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the first LED, and / or the distance between two successive first transition rows moving away from the first LED exhibits a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the first LED.

[0017] According to one embodiment: the value of the first transition diameters of the first transition nanowires of the first transition rows exhibits a linear evolution over at least three successive first transition rows moving away from the first LED, and / or the distance between two successive first transition rows moving away from the first LED exhibits a linear evolution over at least three successive first transition rows moving away from the first LED.

[0018] According to one embodiment, the first nanowires and the first transition nanowires are further organized in rows along the first direction.

[0019] According to one embodiment, the first direction and the second direction are orthogonal.

[0020] According to one embodiment, the first transition sub-zone extends over at least three rows, preferably at least five rows, of first transition nanowires.

[0021] According to one embodiment, the first transition sub-zone has a surface S 1000 and the first LED has a surface S 100 such that S 100 / 5 < S 1000 < S 100 / 2.

[0022] According to one embodiment, the first nanowires on the one hand and the first transition nanowires on the other hand are powered by separate electrical contacts.

[0023] According to one embodiment, the device further comprises: a second LED extending mainly in the plane, said second LED comprising a plurality of second nanowires having second diameters having a value substantially equal to a second target diameter ϕ 20 and organized in N LED,x,2 rows oriented in the second direction, called second rows, and indexed according to a numbering from 1 to N LED,x,2 moving away from the first transition zone in the first direction, said second rows being separated by first distances taken in the first direction having a value substantially equal to a second target distance p 20,x , said second LED being configured to emit a second light beam having mainly a second wavelength λ 2 , said first and second LEDs being separated at least by the first transition zone.

[0024] According to an embodiment N sub-trans,1 = N trans,x,1 and: the value of the first transition diameters of the first transition nanowires of the first transition row n°N sub-trans,1 varies in a proportion less than 5% of the second target diameter ϕ 20 , and / or the second row n°1 and the first transition row n°N sub-trans,1 being separated in the first direction by a second interface distance d interface,2 , the distance in the first direction between the first transition row n°N sub-trans,1 and the first transition row n°N sub-trans,1 -1 vary in a proportion between 2% and 4% of the second interface distance d interface,2 .

[0025] According to one embodiment, the first transition zone comprises a second transition sub-zone formed by the first transition rows n°N sub-trans,2 to N trans,x,1, with N sub-trans,1 ≤ N sub-trans,2 <N trans,x,1 , deuxième sous-zone de transition dans laquelle : the first transition nanowires are such that: i. the value of the first transition diameters of the first transition nanowires of the first transition row n° N trans,x,1 varies in a proportion less than 5% of the second target diameter ϕ 20 , and ii. the value of the first transition diameters of the first transition nanowires of any first transition row n°i, i being between N sub-trans,2 and N trans,x,1 -1 varies in a proportion between 3% and 13% of the value of the first transition diameters of the first transition nanowires of the first transition row n°i+1, and / or the first transition nanowires are such that: i.the second row No. 1 and the first transition row No. N trans,x,1 being separated in the first direction x by a second interface distance d interface,2 , the distance in the first direction (x) between the first transition row No. N trans,x,1 and the first transition row No. N trans,x,1 -1 and the second interface distance d interface,2 vary in a proportion comprised between 2% and 4% of the second interface distance d interface,2 and of the distance in the first direction (x) between the second row No. 1 and the second row No. 2 respectively, ii. the distance in the first direction between any first transition row No. i and the first transition row No. i-1 varies in a proportion comprised between 2% and 4% of the distance in the first direction between the first transition row No. i and the first transition row No. i+1, i being comprised between N trans,x,1 -1 and N sub-trans,2 +1. .

[0026] According to one embodiment: the value of the first transition diameters of the first transition nanowires of the first transition rows exhibits a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the second LED, and / or the distance between two successive first transition rows moving away from the first LED exhibits a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the second LED.

[0027] According to one embodiment: the value of the first transition diameters of the first transition nanowires of the first transition rows exhibits a linear evolution over at least three successive first transition rows moving away from the second LED, and / or the distance between two successive first transition rows moving away from the first LED exhibits a linear evolution over at least three successive first transition rows moving away from the second LED.

[0028] According to one embodiment, the second rows are spaced along the first direction x by a distance called the second pitch p 2 .

[0029] According to an embodiment N sub-trans,1 < N sub-trans,2 and in which: the distance between the first transition rows n°N sub-trans,1 to n°N threshold,1, with N sub-trans,1 <N seuil,1 ≤ N sous-trans,2 est constante et / ou, les premiers diamètres de transition des premiers nanofils de transition des premières rangées de transition n°N sous-trans,1 à n°N seuil,1 , avec N sous-trans,1 <N seuil,1 ≤ N sous-trans,2 sont constants, thus forming a sub-zone called the first threshold sub-zone.

[0030] According to one embodiment at least a portion of the first transition nanowires comprise an active region configured to emit a first transition light beam.

[0031] According to one embodiment, the first transition light beam mainly has a first transition wavelength λ trans,1 , with λ trans,1 ≠ λ 1 and λ trans,1 ≠ λ 2 .

[0032] According to one embodiment: the first nanowires are organized in N LED,y,1 rows oriented in the first direction, called first secondary rows, indexed according to a numbering from 1 to N LED,y,1 and separated by first secondary distances taken in the second direction having a value substantially equal to a first target secondary distance p 10,y , and the second nanowires are organized in N LED,y,2 rows oriented in the first direction, called second secondary rows and indexed according to a numbering from 1 to N LED,y,2 and separated by second secondary distances taken in the second direction having a value substantially equal to a second target secondary distance p 20,y .

[0033] According to one embodiment, the device further comprises: a third LED extending mainly in the plane, said third LED comprising a plurality of third nanowires having third diameters having a value substantially equal to a third target diameter ϕ 30 and organized in N LED,x,3 rows oriented in the second direction, called third rows and in N LED,y,3 rows oriented in the first direction, called third secondary rows, said third LED being configured to emit a third light beam having mainly a third wavelength λ 3 , a second transition zone extending mainly in the plane and at least partly bordering said second LED and said third LED, said second transition zone comprising a plurality of second transition nanowires having second transition diameters and organized in N trans,y,2 rows oriented in the first direction,said second secondary transition rows and indexed according to a numbering from 1 to N trans,y,2 when approaching the second LED in the second direction, a third transition zone extending mainly in the plane and at least partly bordering said third LED and said first LED, said third transition zone comprising a plurality of third transition nanowires having third transition diameters and organized in N trans,y,3 rows oriented in the first direction, said third secondary transition rows and indexed according to a numbering from 1 to N trans,y,3 when approaching the first LED in the second direction, , said second and third LEDs being separated by the second transition zone, said third and first LEDs being separated by the third transition zone, wherein the second nanowires of the second transition zone are such that: i. the value of the second transition diameters of the second transition nanowires of the second transition row No. 1 varies in a proportion less than 5% of the third target diameter ϕ 30 , and ii. the value of the second transition diameter of each second transition nanowire of any second secondary transition row No. i, i being between 2 and N trans,y,2 , varies in a proportion between 3% and 13% of the value of the second transition diameter of the second transition nanowire of the second secondary transition row No. i-1 being closest to it, and iii.the value of the second transition diameters of the second transition nanowires of the second transition row n°N trans,y,2 varies in a proportion less than 5% of the second target diameter ϕ 20 , and / or i. the second secondary row n°1 and the second secondary transition row n°N trans,y,2 being separated in the second direction (y) by a third interface distance d interface,3 , the third interface distance d interface,3 and the distance in the second direction (y) between the second secondary transition row n°N trans,y,2 and the second secondary transition row n° N trans,y,2 -1 vary in a proportion of between 2% and 4% of the distance in the second direction (y) between the second secondary transition row n°N trans,y,2 and the second secondary transition row n°N trans , y,2 -1 and the third interface distance d interface,3 respectively, ii.the distance in the second direction between any second secondary transition row no. i and the second secondary transition row no. i+1 varies in a proportion between 2% and 4% of the distance in the second direction between the second secondary transition row no. i-1 and the second secondary transition row no. i, i being between 2 and N trans,y,2 -1 , and iii.the third secondary row No. N LED,y,3 and the second secondary transition row No. 1 being separated in the second direction by a fourth interface distance d interface,4 , the fourth interface distance d interface,4 and the distance in the second direction between the second secondary transition row No. 2 and the second secondary transition row No. 1 vary in a proportion of between 2% and 4% of the distance in the second direction between the third secondary row No. N LED,y,3 and the third secondary row No. N LED,y,3 -1 and the fourth interface distance d interface,4 respectively, and wherein the third nanowires of the third transition zone are such that: i. the value of the third transition diameters of the third transition nanowires of the third transition row No. 1 varies in a proportion of less than 5% of the third target diameter ϕ 30 , and ii.the value of the third transition diameter of each third transition nanowire of any third secondary transition row n°i, i being between 2 and N trans,y,3 , varies in a proportion between 3% and 13% of the value of the third transition diameter of the third transition nanowire of the third secondary transition row n°i-1 being closest to it, and iii. the value of the third transition diameters of the third transition nanowires of the third transition row n°N trans,y,3 varies in a proportion less than 5% of the first target diameter ϕ 10 , and / or i.the first secondary row No. 1 and the third secondary transition row No. N trans,y,3 being separated in the second direction by a sixth interface distance d interface,6, the sixth interface distance d interface,6 and the distance in the second direction between the third secondary transition row No. N trans,y,3 and the third secondary transition row No. N trans,y,3 -1 vary in a proportion of between 2% and 4% of the distance in the second direction between the third secondary transition row No. N trans,y,3 and the third secondary transition row No. N trans,y,3 -1 and the sixth interface distance d interface,3 respectively, ii.the distance in the second direction between any third secondary transition row no. i and the third secondary transition row no. i+1 varies in a proportion between 2% and 4% of the distance in the second direction between the third secondary transition row no. i-1 and the third secondary transition row no. i, i being between 2 and N trans,y,3 -1 ,and iii.the third secondary row No. N LED,y,3 and the third secondary transition row No. 1 being separated in the second direction by a fifth interface distance d interface , 5 , and the fifth interface distance d interface,5 and the distance in the second direction between the third secondary transition row No. 2 and the third secondary transition row No. 1 vary in a proportion between 2% and 4% of the distance in the second direction between the third secondary row No. N LED,y,3 and the third secondary row No. N LED,y,3 -1 and the fourth interface distance d interface,4 respectively.

[0034] According to one embodiment, the device further comprises an intermediate region bordered by the first transition zone, the second transition zone, the third transition zone and the third LED, said intermediate region comprising a plurality of intermediate nanowires having a diameter distribution such that all of said intermediate nanowires emit at a plurality of wavelengths distributed across the entire visible spectrum.

[0035] A wire or nanowire is understood to mean a 3D structure of elongated shape in the longitudinal direction. The longitudinal dimension of the 3D structure, along z in the figures, is greater, and preferably much greater, than the transverse dimensions of the 3D structure, in the xy plane in the figures. The longitudinal dimension is for example at least five times, and preferably at least ten times, greater than the transverse dimensions.

[0036] Diameter is understood to mean the largest transverse dimension of the nanowire. In the present invention, the 3D structures do not necessarily have a circular cross-section. In particular, in the case of GaN-based 3D structures, this cross-section may be hexagonal. The diameter then corresponds to the distance separating two opposite vertices of the hexagonal cross-section. Alternatively, the diameter may correspond to an average diameter calculated from the diameter of a circle inscribed in the polygon of the cross-section and the diameter of a circumscribed circle of this polygon.

[0037] 3D structures can also have a hexagonal or polygonal cross-section.

[0038] In this patent application, the terms "light-emitting diode", "LED" or simply "diode" are used synonymously. An "LED" can also be understood as a "micro-LED".

[0039] In the following, the following abbreviations relating to a material M are possibly used: Mi refers to the intrinsic or unintentionally doped material M, according to the terminology usually used in the field of microelectronics for the suffix -i. Mn refers to the N, N+ or N++ doped material M, according to the terminology usually used in the field of microelectronics for the suffix -n. Mp refers to the P, P+ or P++ doped material M, according to the terminology usually used in the field of microelectronics for the suffix -p.

[0040] A substrate, a layer, a device, "based" on a material M, is understood to mean a substrate, a layer, a device comprising this material M only or this material M and possibly other materials, for example alloying elements, impurities or doping elements. Thus, a 3D structure based on gallium nitride (GaN) may for example comprise gallium nitride (GaN or GaN-i) or doped gallium nitride (GaN-p, GaN-n). An active region based on gallium-indium nitride (InGaN) may for example comprise gallium-aluminium nitride (AIGaN) or gallium nitride with different aluminium and indium contents (GalnAIN). In the context of the present invention, the material M is generally crystalline.

[0041] A reference frame, preferably orthonormal, comprising the x, y, z axes is shown in the attached figures.

[0042] The terms "substantially", "approximately", "of the order of" mean, when they refer to a value, "within 10%" of that value or, when they refer to an angular orientation, "within 10°" of that orientation. Thus, a direction substantially normal to a plane means a direction presenting an angle of 90±10° with respect to the plane.

[0043] A light beam with a wavelength λ is defined as a beam whose peak wavelength is at wavelength λ. The spectrum of the beam typically follows a Gaussian distribution. The peak of the spectrum is then understood as the maximum value of the Gaussian.

[0044] The term "light beam emitted mainly in a direction d" means a beam whose maximum light intensity is located in the axis defining the direction d.

[0045] To determine the geometry of 3D structures and the compositions of the different elements (wire, active region, collar for example) of these 3D structures, we can carry out Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) analyses or even STEM (Scanning Transmission Electron Microscopy).

[0046] TEM or STEM are particularly well suited to the observation and identification of quantum wells - whose thickness is generally of the order of a few nanometers - in the active region. Different techniques listed below in a non-exhaustive manner can be implemented: dark field and bright field imaging, weak beam imaging, and wide-angle diffraction (HAADF) (acronym for "High Angle Annular Dark Field").

[0047] The chemical compositions of different elements can be determined using the well-known EDX or X-EDS method, an acronym for "energy dispersive x-ray spectroscopy" which means "energy dispersive analysis of X-ray photons".

[0048] This method is well suited for analyzing the composition of small optoelectronic devices such as 3D LEDs. It can be implemented on metallurgical sections within a Scanning Electron Microscope (SEM) or on thin sections within a Transmission Electron Microscope (TEM).

[0049] The optical properties of the various elements, and in particular the main emission wavelengths of GaN-based axial 3D LEDs and / or InGaN-based active regions, can be determined by spectroscopy.

[0050] Cathodoluminescence (CL) and photoluminescence (PL) spectroscopies are well suited to optically characterize the 3D structures described in the present invention.

[0051] The techniques mentioned above make it possible in particular to determine whether an optoelectronic device with an axial 3D structure in the form of a wire comprises InGaN-based quantum wells formed at the top of a GaN-based wire, and a masking layer indicative of an implementation of a MOVPE-type deposition.

[0052] It should be noted that in the chromaticity diagrams shown in Figures 6a And 6b , the coordinates correspond to the x and y trichromatic coordinates typically defined by the CIE XYZ colorimetric system standards.

[0053] As illustrated in the figure 3 , the optoelectronic device 1 which is the subject of the invention typically comprises a substrate 2 extending along the xy plane shown in the figures 1 to 5The substrate has an upper face 20 also extending in the first direction and the second direction. The substrate 2 may be in the form of a stack comprising, in the z direction, a support 21, a surface layer called the nucleation layer 22 and a masking layer 23.

[0054] The support 21 can be made of sapphire to limit the mesh parameter mismatch with GaN, or silicon to reduce costs and for technological compatibility issues. In the latter case, it can be in the form of a wafer with a diameter of 200 mm or 300 mm. It serves in particular as a support for 3D structures.

[0055] The nucleation layer 22 is for example based on AlN. It can alternatively be based on other metal nitrides, for example GaN or AIGaN. It can be formed on the silicon support 21 by epitaxy, preferably by vapor phase epitaxy with organometallic precursors MOVPE (acronym for “MetalOrganic Vapor Phase Epitaxy”). In a known manner, one or more intermediate buffer layers can be arranged between the nucleation layer 22 and the support 21. According to one example, the nucleation layer 22 has a thickness of between 1 nm and 10 µm. It preferably has a thickness of the order of a few hundred nanometers, for example approximately 100 nm or 200 nm, to a few microns, for example of the order of 2 µm. It can also have a thickness of less than 100 nm. Such a thickness makes it possible to limit the appearance of structural defects in the nucleation layer 22.In particular, the growth of this nucleation layer 22 can be pseudomorphic, that is to say that the epitaxial constraints (linked in particular to the difference in lattice parameters between Si and AIN, GaN or AIGaN) can be elastically released during growth. The crystalline quality of this nucleation layer 22 can thus be optimized.

[0056] The masking layer 23 is preferably made of a dielectric material, for example silicon nitride Si3N4. It can be deposited by chemical vapor deposition CVD (acronym for “Chemical Vapor Deposition”) on the nucleation layer 22. It partially masks the nucleation layer 22 and comprises preferably circular openings exposing areas of the nucleation layer 22. These openings typically have different dimensions, for example different diameters, depending on the areas considered, in particular the areas corresponding to the first LED and / or the first transition area and / or the second LED and / or the second transition area etc. The openings can be distributed regularly within each area, for example in the form of an ordered network. Different pitches d, i.e. the distance separating the centers of two adjacent openings 120, can be defined depending on said areas.These openings can be made for example by UV or DUV lithography (acronym for Deep UV), by electron beam lithography or by NIL (acronym for Nanoinprint lithography). Such a masking layer 23 allows localized growth of a 3D structure such as a nanowire from the nucleation layer 22 and at each opening. The lower part of the 3D structure then rests on the nucleation layer of the substrate 2 via its base.

[0057] The optoelectronic device 1 further comprises a first LED 100 arranged on the upper face 20 of the substrate 2 and also extending in the xy plane. This first LED 100 typically comprises at least one active nanowire 101. Such a nanowire 101 advantageously extends from the possible nucleation layer 22 and through an opening of the possible masking layer 23 of the substrate 2. The first LED 100 advantageously comprises a plurality of first active nanowires 101, as shown in all of the figures 1 to 5 .

[0058] The first nanowires 101 have first diameters having a value substantially equal to a target value called the first target diameter ϕ 10 . It is understood that, due to the inaccuracies resulting from the manufacturing methods, the first nanowires 101 can hardly all have a diameter equal to the first target diameter ϕ 10 . A first real diameter denoted ϕ 1,n is therefore defined for each first nanowire, n indexing the first nanowires and therefore varying from 1 to N 1 , N 1 being the number of first nanowires 101. This first real diameter is preferably such that 0.9.ϕ 10 < ϕ 1,n < 1.1.ϕ 10 . The variations in the value of the nanowire diameter due to manufacturing hazards can in fact be estimated at approximately 10% of the target value.

[0059] A first active nanowire 101 comprises an active region 102 and is typically electrically connected. This active region 102 is the site of radiative recombinations of electron-hole pairs making it possible to obtain light radiation having a main wavelength. The active region 102 typically comprises a plurality of quantum wells, for example formed by emissive layers based on GaN, InN, InGaN, AIGaN, AIN, AlInGaN, GaP, AlGaP, AlInGap, AlGaAs, GaAs, InGaAs, AlIAs, or a combination of several of these materials.

[0060] The set of first active nanowires 101 of the first LED 100 preferably forms a photonic crystal which can be described by several parameters and in particular: the emission wavelength, the network pitch, the filling rate, also called opening rate or density, generally between 10 and 90%, the type of mesh (hexagonal, square, etc.), the refractive index of the material filling the spaces between the nanowires 101, commonly called “filler”, preferably between 1 and 1.7, and the dimensions of the nanowires.

[0061] A crystal is typically characterized by the ratio between the lattice pitch and the emission wavelength.

[0062] As illustrated in the figure 8, the first nanowires 101 are advantageously arranged in rows oriented in a first direction and / or a second direction. These rows are called first rows and first secondary rows respectively. In the figures, the first direction and the second direction correspond respectively to the x and y directions of the orthonormal reference frame. Thus, in the figures, the first direction and the second direction are normal. However, it is possible that they are not. The first rows and the first secondary rows are respectively N LED,x,1 and N LED,y,1 in number. They are also identified using an indexing ranging from 1 to N LED,x,1 and from 1 to N LED,y,1 respectively.

[0063] All of these rows and therefore the first nanowires 101 advantageously form a regular two-dimensional network. It may for example be a monoclinic network, an orthorhombic network, a tetragonal network or even a hexagonal network.

[0064] The first rows are advantageously separated by first distances taken along the first direction having a value substantially equal to a first target distance p 10,x . It is understood that due to inaccuracies arising from the manufacturing processes, the distance between two neighboring first rows may vary around the first target distance p 10,x . Variations in the value of the distance between two neighboring first rows due to manufacturing hazards may be estimated at approximately 10% of the target value.

[0065] The first LED 100 typically comprises a layer based on a transparent conductive oxide, commonly referred to as TCO (from the English “Transparent Conductive Oxide”), the thickness of which is preferably between 100 and 300 nm. The nanowires may be arranged, in the longitudinal direction, between a mirror layer based on a metallic material, typically Al, and the TCO layer. This arrangement of the nanowires between the mirror layer and the TCO layer possibly makes it possible to create a Fabry-Perot cavity in the longitudinal direction.

[0066] The first LED 100 is advantageously sized to have dimensions of the order of those of a sub-pixel of a display device.

[0067] The first LED 100 is configured to emit a first light beam 110. Advantageously, the first light beam 110 is configured to be emitted mainly in a direction normal to the substrate 2, i.e. extending parallel to the z axis shown in the figures 1 to 5 , called longitudinal direction. The light beam 110 however comprises a multitude of rays propagating in as many emission directions. The emission is for example omnidirectional. According to another embodiment, the rays of the beam are typically emitted according to a Lambertian or orthotropic profile, that is to say that the luminance of the LED 100 is angularly uniform, but that the luminous intensity emitted depends on the emission direction. The luminous intensity of the beam typically varies according to Lambert's law: I = I 0 cos θ with I the luminous intensity along an emission direction, I 0 the luminous intensity at the source and θ the angle of the emission direction relative to the normal to the source surface, here the longitudinal direction. It is understood that any other emission profile is possible and that the first LED 100 is not limited to a Lambertian source.

[0068] The device 1 further comprises a first transition zone 1000 at least partially bordering the first LED 100.

[0069] The first transition zone 1000 comprises a plurality of first transition nanowires 1001 extending in the transverse direction from the upper face 20 of the substrate 2.

[0070] The first transition nanowires 1001 may be active or passive depending on the intended use. A "passive nanowire" is a nanowire that does not emit light radiation. A passive nanowire is typically similar to an active nanowire but is not electrically connected.

[0071] The first transition nanowires 1001 preferably form a photonic crystal extending over the substrate 2. The parameters used to describe this photonic crystal are the same as those describing the photonic crystal formed by the active nanowires 102 (network pitch, mesh type, filling rate, etc.), with the exception of the emission length which here is not defined when the first transition nanowires are passive.

[0072] The first transition nanowires 1001 are advantageously arranged in rows oriented in the first direction x and / or the second direction y. These rows are called first transition rows and first secondary transition rows and are N trans,x,1 and N trans,y,1 in number respectively. They are also identified using an indexing ranging from 1 to N LED,x,1 moving away from the first LED 100 and from 1 to N LED,y,1 respectively.

[0073] Advantageously, the set of first transition nanowires 1001 forms a regular two-dimensional network, preferably of the same type as the set of first nanowires 101. This makes it possible to optimize the manufacturing of the first LED 100 and the first transition zone 1000, which is advantageously done simultaneously.

[0074] The presence of a transition sub-zone 1100 is provided bordering the first LED 100 and formed by N sub-trans,1 first transition rows, N sub-trans,1 being between 2 and N trans,x,1 . The first transition nanowires 1001 of the first transition sub-zone 1100 have the particularity of having diameters called first transition diameters and / or distances between first consecutive transition rows evolving away from the first LED 100. This particularity makes it possible to avoid an abrupt change in diameter and / or distance between nanowires at the edge of the first LED. This makes it possible to avoid edge effects that are detrimental to the efficiency of the first LED 100.

[0075] The variations in the value of the first transition diameters of the first transition nanowires 1001 or in the value of the distance between two consecutive rows of first transition nanowires moving away from the first LED 100 is indeed fundamental.

[0076] These variations within the first transition sub-zone 1100 may have different progression laws moving away from the first LED 100. The variations in diameters and the variations relating to the distance between two consecutive first transition rows may have similar or distinct progression laws. These variations may, for example, be monotonous or even strictly monotonous, i.e. increasing or decreasing or even strictly increasing or strictly decreasing. The variation of these parameters may also be linear. It is also not excluded that one of the two parameters exhibits an increasing then decreasing evolution moving away from the first LED, or vice versa.The diameter and / or the distance between two consecutive rows may indeed increase in certain regions of the first transition sub-zone 1100 and decrease in other regions of the first transition sub-zone 1100, depending on the intended applications. Advantageously, it is provided that the first transition nanowires 1001 constituting the first transition rows immediately bordering the first LED 100 have first transition diameters varying monotonically over several rows, for example 3 to 5 rows. In the same way, it is advantageously provided that the distance between two first consecutive transition rows varies monotonically over several first transition rows immediately bordering the first LED, for example 3 to 5 rows.The term “first transition rows immediately bordering the first LED” means the first transition rows that are encountered first when moving away from the first LED 100 in the first direction x. In other words, these are the first transition nanowires 1001 having the smallest distance along x to the LED 100, or the smallest indexing.

[0077] Whatever the law followed by the variations in the diameters of the first transition nanowires and the distances between first transition rows within the first transition sub-zone 1100, to avoid any abrupt transition of the first transition diameter and / or the distance between two consecutive rows moving away from the first LED 100, it is expected that these variations are limited. It is expected in particular that moving away from the first LED 100, the diameter of the transition nanowires 1001 of two consecutive rows can only increase or decrease by 3 to 13% of the row preceding it. The pitch between two consecutive rows moving away from the first LED 100 can only increase or decrease by 2 to 4% compared to the pitch preceding it.

[0078] It is also provided, in order to avoid any abrupt transition between the first LED 100 and the first transition zone 1000, that the first transition nanowires 1001 immediately bordering the first LED 100 have a diameter close to the target diameter of the first nanowires 101 of the first LED 100. Their diameter typically varies in a proportion of less than 5% of ϕ 10 .

[0079] In the same vein, any abrupt transition of the distance between nanowires at the interface between the first LED 100 and the first transition zone 1000 is prevented. To do this, a first interface distance d interface,1 is defined separating the first row bordering the first transition zone 1000 (first row n°N LED,x,1 ) and the first transition row bordering the first LED 100 (first transition row n°1). The value of the first interface distance d interface,1 and that of the distance in the first direction x between the first transition row n°1 and the first transition row n°2 vary in a proportion of between 2% and 4% of the distance in the first direction x between the first row n°N LED,1 -1 and the first row n°N LED,1 and the first interface distance d interface,1 respectively.

[0080] It is also conceivable that the first transition zone 1000 comprises a sub-zone bordering the first transition sub-zone, called the threshold sub-zone, in which at least one of the two parameters among the diameter of the first transition nanowires 1001 and the distance between the first neighboring transition rows remains constant when moving away from the first LED 100.

[0081] The electrical power supply of a set of active nanowires is typically carried out in parallel. The active nanowires of the same set are in fact conventionally connected in parallel to an upper electrode and a lower electrode arranged under the substrate 2 from which said active nanowires extend.

[0082] In the context of the invention, it is advantageously provided that the first nanowires 101 of the first LED 100 and the first transition nanowires 1001 of the first transition zone 1000 are powered separately, by separate electrodes. Such a separation makes it possible in particular to control which nanowires are powered and consequently which zones emit. This characteristic finds its full advantage in the application of the present invention relating to the extension of the gamut of the device described later. However, it is not excluded that the first nanowires 101 of the first LED 100 and the first transition nanowires 1001 of the first transition zone 1000 are powered simultaneously by the same electrode.

[0083] According to an advantageous embodiment illustrated in the figure 2, the optoelectronic device 1 comprises a second LED 200 arranged on the upper face of the substrate 2 and adjacent to the first LED 100. The two LEDs 100, 200 can be likened to two adjacent sub-pixels of a display screen.

[0084] The second LED 200 is configured to emit a second light beam 210 being, like the first light beam 110, advantageously configured to be mainly emitted in the transverse direction. The second light beam 210 is for example omnidirectional and typically has a Lambertian profile.

[0085] The second light source 200 comprises at least one second active nanowire 201 extending from the upper face 20 of the substrate 2, and preferably a plurality of second active nanowires 201. The second active nanowires 201 preferably form a photonic crystal that can be described in the same way as the photonic crystal formed by the first active nanowires 101. The second nanowires 201 are advantageously arranged in rows oriented in a first direction and / or a second direction. These rows are called second rows and second secondary rows respectively. The second rows and second secondary rows are respectively N LED,x,2 and N LED,y,2 in number. They are furthermore identified using an indexing ranging from 1 to N LED,x,2 moving away from the first transition zone and from 1 to N LED,y,2 respectively.The second rows are advantageously separated by second distances taken along the first direction having a value substantially equal to a second target distance P 20,x . It is understood that due to the inaccuracies resulting from the manufacturing processes, the distance between two neighboring second rows may vary around the second target distance p 20,x . The variations in the value of the distance between two neighboring second rows due to manufacturing hazards may be estimated at approximately 10% of the target value.

[0086] As for the first nanowires 101, a second real diameter denoted ϕ 2,n is defined for each second nanowire 201, n indexing the second nanowires and therefore varying from 1 to N 2 , N 2 being the number of first nanowires 101. This first real diameter is preferably such that 0.9.ϕ 20 < ϕ 2,n < 1.1.ϕ 20 , ϕ 20 , being a second target diameter.

[0087] The transition zone 1000 separates the first LED 100 and the second LED 200. Several configurations of the transition zone are possible. For example, it is possible to provide that within the transition zone, and therefore separating the first LED 100 and the second LED 200, there are: the first transition sub-zone 1100 as previously described bordering the first LED 100, possibly a second transition sub-zone 1200 bordering the second LED 200, possibly a threshold sub-zone as previously described and separating the first transition sub-zone 1100 and the second transition sub-zone 1200.

[0088] The characteristics of the first transition sub-zone 1100 apply mutatis mutandis to the second transition sub-zone 1200.

[0089] Advantageously, the first transition diameters and / or the distances between first neighboring transition rows vary progressively: from the target value of the first diameters, ϕ 10 , of the first nanowires 101 of the first LED 100, to the target value of the second diameters, ϕ 20 , of the second nanowires 201 of the second LED 200, the values ​​ϕ 10 and ϕ 20 being taken by the diameters of the transition nanowires 1001 of the first transition rows No. 1 and N trans,x,1 respectively, and / or from the first target distance, p 10,x , to the second target distance, p 20,x , the values ​​p 10,x and p 20,x being respectively taken between the first transition row No. 1 and the first transition row No. 2 on the one hand and the first transition row No. N trans,x,1 -1 and the first transition row No. N trans,x,1 on the other hand, respectively.

[0090] There figure 2 illustrates for example the case where the diameter of the transition nanowires 1001 varies from ϕ 10 to ϕ 20 when crossing the transition zone 1000 from the first LED 100 to the second LED 200.

[0091] There figure 3 illustrates in particular the case where the distance between two successive first transition rows varies from p 10,x to p 20,x when crossing the transition zone 1000 from the first LED 100 to the second LED 200.

[0092] This preferably continuous or even monotonous variation forms a smooth transition between the first and second LEDs 100, 200. This makes it possible to avoid breaks in symmetry between the different nanowire networks forming the first and second LEDs 100, 200. Edge effects are thus advantageously limited or eliminated.

[0093] Preferably, this variation of the first transition diameters and / or the distances between first neighboring transition rows is linear.

[0094] The embodiments described above, in which the device 1 comprises a transition zone and respectively one and two LEDs, can be extended to devices comprising a greater number of LEDs and transition zones. A device with three LEDs 100, 200, 300 and two transition zones 1000, 2000 respectively separating the first and second LEDs 100, 200 on the one hand and the second and a third LED 200, 300 on the other hand, is for example illustrated in Figure 5. According to one possibility, the device comprises three LEDs 100, 200, 300 and three transition zones 1000, 2000, 3000, the first transition zone 1000 separating the first and second LEDs 100, 200, the second transition zone 2000 separating the second and third LEDs and the third transition zone 3000 separating the third and first LEDs. This embodiment makes it possible in particular to produce RGB pixels consisting of three sub-pixels R, G, B, corresponding to the three LEDs 100, 200, 300, emitting respectively in red (R designating “red” i.e. red), green (G designating “green” i.e. green) and blue (B designating “blue” i.e. blue).

[0095] It is also conceivable that the device 1 comprises four LEDs 100, 200, 300, 400 separated by four transition zones 1000, 2000, 3000, 4000 as shown in the Figure 4b .

[0096] The characteristics of the first and second LEDs 100, 200 described above apply mutatis mutandis to the third and fourth LEDs 300, 400. As illustrated in Figure 4b , the latter typically comprise respectively third nanowires 301 and fourth nanowires 401 having respectively a third target diameter ϕ 30 and a fourth target diameter ϕ 40 and ordered in rows oriented in the second direction. These rows are typically themselves spaced in the first direction by a third target distance p 30,x and a fourth target distance p 40,x, respectively.

[0097] The characteristics of the first transition zone 1000 described above apply mutatis mutandis to the three transition zones 2000, 3000, 4000.

[0098] According to an advantageous embodiment of the present invention, at least a portion of the nanowires of the transition zone(s) are active nanowires and are used to extend the range of colors that can be rendered by the device 1.

[0099] The figures, and in particular the Figures 6a , 6b And 7 , illustrate this embodiment applied to a device with four LEDs emitting three native colors (C1, C2 and C3), but it is understood that this principle can be applied to any device comprising more than two LEDs.

[0100] The colors usually emitted by the sub-pixels of the same pixel are red (C1 on the chromaticity diagram shown in Figure 6a), green (C2 on the chromaticity diagram) and blue (C3 on the chromaticity diagram). However, other colors can be rendered from such a pixel. All colors included in gamut 4 defined by the colors emitted by the three sub-pixels on the chromaticity diagram of the CIE XYZ colorimetric system can be obtained by linear combinations of the three native colors. For example, it is possible, by turning off the sub-pixel emitting in the blue and by linear combination of the red and green beams, to make the color perceived by an observer yellow. However, not all the hues of the spectrum locus, that is to say the set of pure colors perceptible by human vision, are included in gamut 4 characterizing the hues that can be generated by the pixel. Some hues located outside gamut 4 could however be necessary to render an image faithfully.Transition zones can be used to advantage to reach these hues of the locus 3 spectrum located outside of gamut 4.

[0101] Indeed, the parameters characterizing all the transition nanowires of a transition zone separating two LEDs can be configured so that this zone emits a beam whose wavelength is outside the gamut 4. Among these parameters is in particular the diameter of each of the transition nanowires.

[0102] It is for example conceivable that, on several consecutive rows, the transition nanowires 1001 are all configured to emit a beam at the same wavelength called transition wavelength λ trans , distinct from the wavelengths emitted by said adjacent LEDs. The wavelength of the overall beam obtained by the superposition of the beams emitted by each of these transition nanowires 1001 is then also λ trans .

[0103] According to another embodiment, it is provided that the overall beam at the wavelength λ trans lying outside the gamut 4 is generated by a set of transition nanowires 1001. This is in fact made possible by an averaging effect of the individual beams generated by each of the transition nanowires 1001 involved. These transition nanowires 1001 can moreover quite easily have parameters (pitch, diameters) varying progressively, as described previously.

[0104] In any case, the transition wavelength λ trans is chosen to be advantageous in the context of image display.

[0105] As mentioned previously, the first nanowires 101 of the first LED 100 and the first transition nanowires 1001 of the first transition zone 1000 are advantageously electrically powered independently of each other, by separate electrodes. This makes it possible to power only the first transition nanowires 1001. The device 1 can then emit only the color corresponding to said transition zone. The possibility of isolating this color can be particularly advantageous for the rendering of certain images.

[0106] According to an advantageous embodiment, it is provided that all of the first transition nanowires of a threshold sub-zone as described above and separating a first LED 100 and a second LED 200 are configured to emit a wavelength λ trans distinct from λ 1 and λ 2 .

[0107] According to a particularly advantageous embodiment shown in the figure 7, the device 1 comprises an intermediate region 500 comprising a plurality of intermediate nanowires 501 configured so that the intermediate region emits a beam of white light. This embodiment is particularly suitable for devices 1 comprising three or four LEDs separated two by two by transition zones. As shown in the figure 7, the intermediate region 500 is, in this example, bordered by the first, second and third transition zones 1000, 2000, 3000 as well as the third LED 300. The intermediate nanowires 501 have in particular a variety of diameters making it possible to emit at a plurality of wavelengths distributed substantially over the entire visible spectrum. The intermediate region 500 thus advantageously generates, by an averaging effect, a beam of substantially white light. The diameters of the intermediate nanowires 501 immediately bordering each of the transition zones 1000, 2000, 3000 are further chosen so as to avoid any abrupt transition, on the model of a transition zone as described previously. It should be noted that the dimensioning of the nanowire network of the intermediate region 500 (pitch, diameter), must take into account the value of the current injected into each of the intermediate nanowires.The light power emitted by these intermediate nanowires 501 depends on this current, and even at constant current, it is not equal from one nanowire to another when they emit at different wavelengths. The sizing of the intermediate nanowires 501 must therefore be done accordingly: obtaining white light depends on the number of intermediate nanowires 501 emitting at each wavelength and the power emitted by each of them. Typically, the intermediate region 500 is powered by a single electrode: the injected current is then identical for each of the intermediate nanowires 501. However, it is conceivable that several electrodes are provided to power different sets of intermediate nanowires 501. This makes it possible to adjust the sizing of the intermediate nanowires 501 more precisely and to facilitate obtaining white light.

[0108] It is understood that this embodiment applies to any device according to the invention comprising a number of LEDs greater than three.

[0109] Through the various embodiments described above, it appears clearly that the invention proposes an effective solution to the problems due to edge effects around the pixels and sub-pixels of display screens, as well as to the current limitations of the gamut of these same screens.

[0110] The invention is however not limited to the embodiments previously described.

[0111] In particular, the number, shape and arrangement of each element of the device can be adapted according to display needs.

[0112] The scope of the present invention is as defined by the following claims.

Claims

1. An optoelectronic device (1) comprising at least: - a first LED (100) extending mainly in a plane (xy) defined by a first direction (x) and a second direction (y), said first LED (100) comprising a plurality of first nanowires (101) having first diameters having a value substantially equal to a first target diameter ϕ10 and organised into NLED,x,1 rows oriented in the second direction (y), called first rows, said first rows being separated by first distances taken in the first direction (x) having a value substantially equal to a first target distance p10,x, said first LED (100) being configured to emit a first light beam having mainly a first wavelength λ1, and - a first transition area (1000) extending mainly in the plane (xy) and at least partly bordering said first LED (100), said first transition area (1000) comprising a plurality of first transition nanowires (1001) having first transition diameters and organised into Ntrans,x,1 rows oriented in the second direction (y), called first transition rows and indexed according to a numbering from 1 to Ntrans,x,1 moving away from the first LED (100) in the first direction (x), the first rows being indexed according to a numbering from 1 to NLED,x,1 in the first direction (x) approaching the first transition area (1000), the device being characterised in that the first transition area (1000) comprises a first transition sub-area (1100) formed by the Nsub-trans,1 first transition rows, with 2 ≤ Nsub-trans,1 ≤ Ntrans,x,1, bordering the first LED (100), first transition sub-area (1100) wherein: - the first transition nanowires (1001) are such that: i. the value of the first transition diameters of the first transition nanowires (1001) of the first transition row n°1 varies in a proportion less than 5% of the first target diameter ϕ10, and ii. the value of the first transition diameter of the first transition nanowire (1001) of any first transition row n°i, i being comprised between 2 and Nsub-trans,1, varies in a proportion comprised between 3% and 13% of the value of the first transition diameter of the first transition nanowire (1001) of the first transition row n°i-1 being closest thereto, and / or - the first transition nanowires (1001) are such that: i. the first row n°NLED,x,1 and the first transition row n°1 being separated in the first direction x by a first interface distance dinterface,1, the first interface distance dinterface,1 and the distance in the first direction (x) between the first transition row n°1 and the first transition row n°2 vary in a proportion comprised between 2% and 4% of the distance in the first direction (x) between the first row n°NLED,x,1-1 and the first row n°NLED,x,1 and the first interface distance dinterface,1 respectively, and ii. the distance in the first direction (x) between any first transition row n°i and the first transition row n°i+1 varies in a proportion comprised between 2% and 4% of the distance in the first direction (x) between the first transition row n°i-1 and the first transition row n°i, i being comprised between 2 and Nsub-trans,1-1.

2. The optoelectronic device (1) according to the preceding claim wherein the first transition diameters of the first transition nanowires (1001) of the same first transition row are equal.

3. The optoelectronic device (1) according to any one of the preceding claims wherein: - the value of the first transition diameters of the first transition nanowires (1001) of the first transition rows has a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the first LED (100), and / or - the distance between two successive first transition rows moving away from the first LED (100) has a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the first LED (100).

4. The optoelectronic device (1) according to the preceding claim wherein: - the value of the first transition diameters of the first transition nanowires (1001) of the first transition rows has a linear evolution over at least three successive first transition rows moving away from the first LED (100), and / or - the distance between two successive first transition rows moving away from the first LED (100) has a linear evolution over at least three successive first transition rows moving away from the first LED (100).

5. The optoelectronic device (1) according to the preceding claim wherein the first nanowires (101) and the first transition nanowires (1001) are further organised into rows in the first direction (x).

6. The optoelectronic device (1) according to any one of the preceding claims wherein the first transition sub-area (1100) extends over at least three rows, preferably at least five rows, of first transition nanowires (1001).

7. The optoelectronic device (1) according to any one of the preceding claims wherein the first transition sub-area (1100) has a surface S1000 and the first LED (100) has a surface S100 such that S100 / 5 < S1000 < S100 / 2.

8. The optoelectronic device (1) according to any one of the preceding claims wherein the first nanowires (101) on the one hand and the first transition nanowires (1001) on the other hand are supplied by separate electrical contacts.

9. The optoelectronic device (1) according to any one of the preceding claims further comprising: - a second LED (200) extending mainly in the plane (xy), said second LED (200) comprising a plurality of second nanowires (201) having second diameters having a value substantially equal to a second target diameter ϕ20 and organised into NLED,x,2 rows oriented in the second direction (y), called second rows, and indexed according to a numbering from 1 to NLED,x,2 moving away from the first transition area (1000) in the first direction (x), said second rows being separated by first distances taken in the first direction (x) having a value substantially equal to a second target distance p20,x, said second LED (200) being configured to emit a second light beam having mainly a second wavelength λ2, said first and second LEDs (100, 200) being separated at least by the first transition area (1000).

10. The optoelectronic device (1) according to the preceding claim wherein NSub-trans,1 = Ntrans,x,1 and wherein: - the value of the first transition diameters of the first transition nanowires (1001) of the first transition row n°Nsub-trans,1 varies in a proportion of less than 5% of the second target diameter ϕ20, and / or - the second row n°1 and the first transition row noNsub-trans,1 being separated in the first direction (x) by a second interface distance dinterface,2, - the distance in the first direction (x) between the first transition row n°Nsub-trans,1 and the first transition row n°Nsub-trans,1-1 varies in a proportion comprised between 2% and 4% of the second interface distance dinterface,2.

11. The optoelectronic device (1) according to claim 9 wherein the first transition area (1000) comprises a second transition sub-area (1200) formed by the first transition rows n°Nsub-trans,2 to Ntrans,x,1, with Nsub-trans,1 ≤ Nsub-trans,2 ≤ Ntrans,x,1, second transition sub-area (1200) wherein: - the first transition nanowires (1001) are such that: i. the value of the first transition diameters of the first transition nanowires (1001) of the first transition row n°Ntrans,x,1 varies in a proportion less than 5% of the second target diameter ϕ20, and ii. the value of the first transition diameters of the first transition nanowires (1001) of any first transition row n°i, i being comprised between Nsub-trans,2 and Ntrans,x,1-1 varies in a proportion comprised between 3% and 13% of the value of the first transition diameters of the first transition nanowires (1001) of the first transition row n°i+1, and / or - the first transition nanowires (1001) are such that: i. the second row n°1 and the first transition row n°Ntrans,x,1 being separated in the first direction x by a second interface distance dinterface,2, the distance in the first direction (x) between the first transition row n°Ntrans,x,1 and the first transition row n°Ntrans,x,1-1 and the second interface distance dinterface,2 vary in a proportion comprised between 2% and 4% of the second interface distance dinterface,2 and the distance in the first direction (x) between the second row n°1 and the second row n°2 respectively, ii. the distance in the first direction (x) between any first transition row n°i and the first transition row n°i-1 varies in a proportion comprised between 2% and 4% of the distance in the first direction (x) between the first transition row n°i and the first transition row n°i+1, i being comprised between Ntrans,x,1-1 and Nsub-trans,2+1.

12. The optoelectronic device (1) according to the preceding claim wherein: - the value of the first transition diameters of the first transition nanowires (1001) of the first transition rows has a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the second LED (200), and / or - the distance between two successive first transition rows moving away from the first LED (100) has a strictly increasing or strictly decreasing evolution over at least three successive first transition rows moving away from the second LED (200).

13. The optoelectronic device (1) according to the preceding claim wherein: - the value of the first transition diameters of the first transition nanowires (1001) of the first transition rows has a linear evolution over at least three successive first transition rows moving away from the second LED (200), and / or - the distance between two successive first transition rows moving away from the first LED (100) has a linear evolution over at least three successive first transition rows moving away from the second LED (200).

14. The optoelectronic device (1) according to any one of the preceding claims wherein at least part of the first transition nanowires (1001) comprise an active region (1002) configured to emit a first transition light beam which mainly has a first transition wavelength λtrans,1, with λtrans,1 ≠ λ1 and λtrans,1 ≠ λ2.

15. The optoelectronic device (1) according to any one of claims 9 to 14 wherein: - the first nanowires (101) are organised into NLEE,y,1 rows oriented in the first direction (x), called first secondary rows, indexed according to a numbering from 1 to NLED,y,1 and separated by first secondary distances taken in the second direction (y) having a value substantially equal to a first target secondary distance p10,y, and - the second nanowires (201) are organised into NLEE,y,2 rows oriented in the first direction (x), called second secondary rows and indexed according to a numbering from 1 to NLED,y,2 and separated by second secondary distances taken in the second direction (y) having a value substantially equal to a second target secondary distance P20,y.

16. The optoelectronic device (1) according to the preceding claim further comprising: - a third LED (300) extending mainly in the plane (xy), said third LED (300) comprising a plurality of third nanowires (301) having third diameters having a value substantially equal to a third target diameter ϕ30 and organised into NLED,x,3 rows oriented in the second direction (y), called third rows and into NLEE,y,3 rows oriented in the first direction (x), called third secondary rows, said third LED (300) being configured to emit a third light beam having mainly a third wavelength λ3, - a second transition area (2000) extending mainly in the plane (xy) and at least partly bordering said second LED (200) and said third LED (300), said second transition area (2000) comprising a plurality of second transition nanowires (2001) having second transition diameters and organised into Ntrans,y,2 rows oriented in the first direction (x), called second secondary transition rows and indexed according to a numbering from 1 to Ntrans,y,2 approaching the second LED (200) in the second direction (y), - a third transition area (3000) extending mainly in the plane (xy) and at least partly bordering said third LED (300) and said first LED (100), said third transition area (3000) comprising a plurality of third transition nanowires (3001) having third transition diameters and organised into Ntrans,y,3 rows oriented in the first direction (x), called third secondary transition rows and indexed according to a numbering from 1 to Ntrans,y,3 approaching the first LED (100) in the second direction (y), said second and third LEDs (200, 300) being separated by the second transition area (2000), said third and first LEDs (300, 100) being separated by the third transition area (3000), wherein the second nanowires of the second transition area (2000) are such that: i. the value of the second transition diameters of the second transition nanowires (2001) of the second transition row n°1 varies in a proportion less than 5% of the third target diameter ϕ30, and ii. the value of the second transition diameter of each second transition nanowire (2001) of any second secondary transition row n°i, i being comprised between 2 and Ntrans,y,2, varies in a proportion comprised between 3% and 13% of the value of the second transition diameter of the second transition nanowire (2001) of the second secondary transition row n°i-1 closest thereto, and iii. the value of the second transition diameters of the second transition nanowires (2001) of the second transition row n°Ntrans,y,2 varies in a proportion less than 5% of the second target diameter ϕ20, and / or i. the second secondary row n°1 and the second secondary transition row n°Ntrans,y,2 being separated in the second direction (y) by a third interface distance dinterface,3, the third interface distance dinterface,3 and the distance in the second direction (y) between the second secondary transition row n°Ntrans,y,2 and the second secondary transition row n°Ntrans,y,2-1 vary in a proportion comprised between 2% and 4% of the distance in the second direction (y) between the second secondary transition row n°Ntrans,y,2 and the second secondary transition row n°Ntrans,y,2-1 and the third interface distance dinterface,3 respectively, ii. the distance in the second direction (y) between any second secondary transition row n°i and the second secondary transition row n° i + 1 varies in a proportion comprised between 2% and 4% of the distance in the second direction (y) between the second secondary transition row n°i-1 and the second secondary transition row n°i, i being comprised between 2 and Ntrans,y,2-1, and iii. the third secondary row n°NLED,y,3 and the second secondary transition row n°1 being separated in the second direction (y) by a fourth interface distance dinterface,4, the fourth interface distance dinterface,4 and the distance in the second direction (y) between the second secondary transition row n°2 and the second secondary transition row n°1 vary in a proportion comprised between 2% and 4% of the distance in the second direction (y) between the third secondary row n°NLED,y,3 and the third secondary row n°NLED,y,3-1 and the fourth interface distance dinterface,4 respectively, and wherein the third nanowires of the third transition area (3000) are such that: i. the value of the third transition diameters of the third transition nanowires (3001) of the third transition row n°1 varies in a proportion less than 5% of the third target diameter ϕ30, and ii. the value of the third transition diameter of each third transition nanowire (3001) of any third secondary transition row n°i, i being comprised between 2 and Ntrans,y,3, varies in a proportion comprised between 3% and 13% of the value of the third transition diameter of the third transition nanowire (3001) of the third secondary transition row n°i-1 closest thereto, and iii. the value of the third transition diameters of the third transition nanowires (3001) of the third transition row n°Ntrans,y,3 varies in a proportion less than 5% of the first target diameter ϕ10, and / or i. the first secondary row n°1 and the third secondary transition row n°Ntrans,y,3 being separated in the second direction (y) by a sixth interface distance dinterface,6, the sixth interface distance dinterface,6 and the distance in the second direction (y) between the third secondary transition row n°Ntrans,y,3 and the third secondary transition row n°Ntrans,y,3-1 vary in a proportion comprised between 2% and 4% of the distance in the second direction (y) between the third secondary transition row n°Ntrans,y,3 and the third secondary transition row n°Ntrans,y,3-1 and the sixth interface distance dinterface,3 respectively, ii. the distance in the second direction (y) between any third secondary transition row n°i and the third secondary transition row n° i + 1 varies in a proportion comprised between 2% and 4% of the distance in the second direction (y) between the third secondary transition row n°i-1 and the third secondary transition row n°i, i being comprised between 2 and Ntrans,y,3-1, and iii. the third secondary row n°NLED,y,3 and the third secondary transition row n°1 being separated in the second direction (y) by a fifth interface distance dintertace,5, the fifth interface distance dinterface,5 and the distance in the second direction (y) between the third secondary transition row n°2 and the third secondary transition row n°1 vary in a proportion comprised between 2% and 4% of the distance in the second direction (y) between the third secondary row n°NLED,y,3 and the third secondary row n°NLED,y / 3-1 and the fourth interface distance dinterface,4 respectively.