High-power and high-efficiency single-mode semiconductor light-emitting structure and preparation method thereof

Abstract

The invention provides a high-power and high-efficiency single-mode semiconductor light-emitting structure and a preparation method thereof, the high-power and high-efficiency single-mode semiconductor light-emitting structure comprises a first Bragg reflector and a second Bragg reflector which are arranged along a first direction, and the reflectivity of the first Bragg reflector is greater than that of the second Bragg reflector; the multiple active layers are located between the first Bragg reflector and the second Bragg reflector and arranged in the first direction; the current limiting layer comprises a light emitting region and an oxidation region surrounding the light emitting region; the tunnel junctions are positioned between the adjacent active layers; the modulation layer is located on the side, away from the active layer, of the second Bragg reflector, the modulation layer comprises a first microstructure region and a second microstructure region surrounding the first microstructure region, the first microstructure region has a projection on a first part of the light emitting region in the first direction, and the second microstructure region has a projection on a second part of the light emitting region in the second direction; the second microstructure region has a projection on a second part of the light emitting region along the first direction, and the second part surrounds the first part.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a high-power and high-efficiency single-mode semiconductor light-emitting structure and a preparation method thereof. Background Art

[0002] In recent years, the application of high-power multi-transverse mode vertical cavity surface emitting lasers (VCSELs) has developed rapidly. They have been widely used in 3D face recognition, autonomous driving, high bit rate data communication and other fields. The power and efficiency of multi-transverse mode vertical cavity surface emitting lasers have been improved to a certain extent. However, the performance improvement of single transverse mode vertical cavity surface emitting lasers in terms of power and efficiency has been slow. Therefore, due to the low power, single transverse mode vertical cavity surface emitting lasers are usually only used for short-distance requirements in data centers and quantum sensing fields with low precision requirements. Especially in the field of high-speed communications, with the adoption of the four-level pulse amplitude modulation PAM4 (4-Level Pulse Amplitude Modulation) scheme, the importance of power has become increasingly prominent. Therefore, the development of high-power single transverse mode vertical cavity surface emitting lasers is of vital importance.

[0003] Since 2005, the output power of single-transverse mode vertical cavity surface emitting lasers has remained stable in the range of 6mW to 8mW. Until 2021, a single-transverse mode vertical cavity surface emitting laser with a laser output of 10mW was achieved through an improved zinc diffusion process, but its electro-optical conversion efficiency is still very low, only about 12%. It is particularly emphasized that the high-efficiency realization of single-mode vertical cavity surface emitting lasers is the focus of current research on vertical cavity surface emitting lasers in the communication field, because it helps to reduce the overall power consumption of data centers. In addition, single-mode vertical cavity surface emitting lasers also show energy-saving potential in emerging applications, such as in brain-like photonic computing and deep learning based on vertical cavity surface emitting lasers. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is how to effectively improve the power and efficiency of a single-mode semiconductor light-emitting structure, thereby providing a high-power and high-efficiency single-mode semiconductor light-emitting structure and a preparation method thereof.

[0005] The present application provides a high-power and high-efficiency single-mode semiconductor light-emitting structure, comprising: a first Bragg reflector and a second Bragg reflector arranged along a first direction, wherein the reflectivity of the first Bragg reflector is greater than the reflectivity of the second Bragg reflector; a plurality of active layers arranged along the first direction between the first Bragg reflector and the second Bragg reflector, and a current limiting layer; wherein the current limiting layer comprises a light emitting region and an oxidation region surrounding the light emitting region; a tunnel junction located between adjacent active layers; a modulation layer located on a side of the second Bragg reflector away from the active layer, wherein the modulation layer comprises a first microstructure region and a second microstructure region surrounding the first microstructure region, wherein the first microstructure region has a projection on a first part of the light emitting region along the first direction, the second microstructure region has a projection on a second part of the light emitting region along the first direction, and the second part surrounds the first part.

[0006] Optionally, a size of the first microstructure area along the second direction is 20% to 35% of a size of the light exit area along the second direction; wherein the second direction is perpendicular to the first direction.

[0007] Optionally, a reflectivity of the second Bragg reflector is less than or equal to 92%.

[0008] Optionally, the overall reflectivity range of the second Bragg reflector and the modulation layer has a lower limit value and an upper limit value, and the ratio of the difference between the upper limit value and the lower limit value to the upper limit value is greater than or equal to 25%.

[0009] Optionally, the thickness of the first microstructure region of the modulation layer in the first direction is 1 / 4 of the central wavelength of light emitted by the high-power and high-efficiency single-mode semiconductor light-emitting structure.

[0010] Optionally, the material of the modulation layer is a semiconductor material or an insulating dielectric material.

[0011] Optionally, the first microstructure region is a solid structure, and the second microstructure region is a groove; or, the first microstructure region is a first grating structure, and the second microstructure region is a second grating structure, and the first grating structure and the second grating structure have different grating periods.

[0012] Optionally, it also includes: an ohmic contact layer located between the modulation layer and the second Bragg reflector.

[0013] Optionally, it also includes: a front electrode layer, located on the side of the modulation layer along the second direction, the front electrode layer and the modulation layer have overlapping projections in the second direction; wherein the second microstructure area is located between the first microstructure area and the front electrode layer; wherein the second direction is perpendicular to the first direction.

[0014] The present application also provides a method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure, comprising: forming a plurality of active layers, tunnel junctions, current limiting layers and second Bragg reflectors arranged along the first direction on one side of a first Bragg reflector along the first direction; the reflectivity of the first Bragg reflector is greater than the reflectivity of the second Bragg reflector; the active layer and the current limiting layer are both located between the first Bragg reflector and the second Bragg reflector, and the tunnel junction is located between adjacent active layers; wherein the current limiting layer comprises a light emitting region and an oxidation region surrounding the light emitting region; forming a modulation layer on the side of the second Bragg reflector away from the active layer, the modulation layer comprising a first microstructure region and a second microstructure region surrounding the first microstructure region, wherein the first microstructure region has a projection on a first part of the light emitting region along the first direction, the second microstructure region has a projection on a second part of the light emitting region along the first direction, and the second part surrounds the first part.

[0015] Optionally, the step of forming the modulation layer includes: forming an initial modulation layer on a side of the second Bragg reflector away from the active layer; and etching the initial modulation layer to form the modulation layer.

[0016] The technical solution of the present invention has the following beneficial effects: The high-power and high-efficiency single-mode semiconductor light-emitting structure provided by the technical solution of the present invention has multiple active layers cascaded through tunnel junctions, which can achieve higher gain in the cavity, thereby achieving higher power output. The introduction of the modulation layer will reduce the proportion of losses in the cavity, thereby achieving an improvement in efficiency. Higher gain can support the reduction of the second Bragg reflector with a low reflectivity while maintaining a low threshold current. In addition, due to the provision of the modulation layer, the overall reflectivity range of the second Bragg reflector and the modulation layer is increased, and a wider range of reflectivity modulation is achieved. Since the second Bragg reflector has a low reflectivity, and the second Bragg reflector and the modulation layer as a whole achieve a wider range of reflectivity modulation, the modulation ability of the modulation layer to the light field in the cavity can be improved, so that the gain difference between the modes can be achieved, thereby achieving a higher power single-mode power output. In addition, since the modulation layer is provided to achieve a wider range of reflectivity modulation, more light is emitted, which further increases the power. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 1 A schematic diagram of a high-power and high-efficiency single-mode semiconductor light-emitting structure according to an embodiment of the present application; Figure 2 Schematic diagram of the change in position of the reflectivity along the second direction obtained for the comparative example and the test example. DETAILED DESCRIPTION

[0019] After research, it was found that the reasons why single-mode vertical cavity surface emitting lasers are limited in power and efficiency come from multiple key factors. First, as a microcavity laser, the gain volume of the vertical cavity surface emitting laser along the light output direction is very small, resulting in low round-trip gain. Secondly, in order to ensure single transverse mode output, the lateral size of the vertical cavity surface emitting laser is severely limited, and the aperture of the light-emitting area is usually less than 3 microns. This small aperture design limits the lateral gain volume, thereby reducing the emission power of the vertical cavity surface emitting laser and greatly increasing the series resistance, thereby exacerbating the self-heating effect of the vertical cavity surface emitting laser. The self-heating effect further limits the upper limit of its driving current, hindering the possibility of achieving high-power single transverse mode laser output. In order to obtain high-power single transverse mode laser output, a variety of strategies have been proposed. One method is to increase the aperture of the light-emitting area to enhance the lateral gain volume and reduce its series resistance. However, simply increasing the aperture of the light-emitting area cannot directly obtain single transverse mode laser output. This is because while increasing the aperture of the light-emitting area, the threshold gain difference of its transverse mode continues to decrease, so that the vertical cavity surface emitting laser cannot directly achieve single transverse mode laser output. Therefore, this method also needs to adjust the threshold gain difference between the higher-order mode and the fundamental transverse mode through technical means, while expanding the aperture of the light-emitting area. Various technologies, such as zinc diffusion, high-contrast gratings, surface relief, triangular hole structure, photonic crystal and anti-waveguide cavity, are used to adjust the threshold gain difference between the fundamental transverse mode and the higher-order mode. However, in single-junction vertical cavity surface emitting lasers, most of these methods introduce structures above the light-emitting layer to achieve the regulation of the threshold gain difference between modes. In order to maintain low threshold operation, the surface reflectivity of single-junction vertical cavity surface emitting lasers is usually designed to be very high, up to 98% or more, making it difficult for these methods to effectively regulate the intracavity mode, resulting in a limited single-mode operating range. In short, the increase in the lateral gain area is limited, the suppression ratio between the fundamental mode and the higher-order mode is insufficient, and it is difficult to significantly increase the power. Secondly, the reflectivity of the top Bragg reflector used in the design of the vertical cavity surface emitting laser is usually more than 98%, and a very high Bragg reflector logarithm is required to achieve this reflectivity. However, this design significantly increases the series resistance, resulting in an enhanced Joule heating effect. Doped Bragg reflectors also introduce free-carrier absorption, and the introduced microstructures increase internal losses, making it difficult to achieve high efficiency in single-mode vertical cavity surface emitting lasers. At the same time, surface microstructures, including metasurfaces, continuous bound state photonic crystal structures, topological photonics, and high-contrast gratings, can also be used for beam modulation of vertical cavity surface emitting lasers. However, the high surface reflectivity in these designs leads to weak coupling between the surface structure and the oscillations in the laser cavity, limiting the ability of the microstructure to regulate the optical mode.

[0020] On this basis, the embodiments of the present application provide a high-power and high-efficiency single-mode semiconductor light-emitting structure, which effectively improves the power and efficiency of the single-mode semiconductor light-emitting structure.

[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] An embodiment of the present invention provides a high-power and high-efficiency single-mode semiconductor light-emitting structure, referring to Figure 1 ,include: A first Bragg reflector 3 and a second Bragg reflector 20 arranged along a first direction Z, wherein the reflectivity of the first Bragg reflector 3 is greater than the reflectivity of the second Bragg reflector 20; A plurality of active layers and a current limiting layer arranged along the first direction Z between the first Bragg reflector 3 and the second Bragg reflector 20; wherein the current limiting layer comprises a light emitting region and an oxidation region surrounding the light emitting region; A tunnel junction located between adjacent active layers; The modulation layer 22 is located on the side of the second Bragg reflector 20 away from the active layer, and the modulation layer 22 includes a first microstructure area 22a and a second microstructure area 22b surrounding the first microstructure area 22a, wherein the first microstructure area 22a has a projection on a first part of the light exit area along the first direction Z, and the second microstructure area 22b has a projection on a second part of the light exit area along the first direction Z, and the second part surrounds the first part.

[0025] In the high-power and high-efficiency single-mode semiconductor light-emitting structure of the embodiment of the present application, multiple active layers are cascaded through tunnel junctions, which can achieve higher gain in the cavity, thereby achieving higher power output. The introduction of the modulation layer 22 will reduce the proportion of intracavity losses, thereby achieving efficiency improvement. Higher gain can support the reduction of the second Bragg reflector 20 having a low reflectivity while maintaining a low threshold current. In addition, due to the provision of the modulation layer, the overall reflectivity range of the second Bragg reflector 20 and the modulation layer 22 is increased, and a wider range of reflectivity modulation is achieved. Since the second Bragg reflector 20 has a low reflectivity, and the second Bragg reflector 20 and the modulation layer 22 as a whole achieve a wider range of reflectivity modulation, the modulation ability of the modulation layer 22 to the intracavity light field can be improved, so that the gain difference between modes can be achieved, thereby achieving a higher power single-mode power output. In addition, since the modulation layer 22 is provided to achieve a wider range of reflectivity modulation, more light is emitted, which further increases the power.

[0026] In addition, higher power output is achieved while the operating current can be greatly reduced, thereby improving reliability and extending life.

[0027] The high-power and high-efficiency single-mode semiconductor light-emitting structure is a surface-emitting semiconductor light-emitting device, such as a surface-emitting semiconductor laser.

[0028] In this embodiment, the reflectivity of the second Bragg reflector 20 is less than or equal to 92%, for example, 70% to 92%.

[0029] In this embodiment, the reflectivity of the second Bragg reflector 20 is lower than that of the second Bragg reflector used in the prior art. The reflectivity of the second Bragg reflector 20 is lower, and the number of Bragg reflector pairs in the second Bragg reflector 20 can be reduced, thereby reducing the series resistance and the Joule heating effect.

[0030] In some embodiments, conductive ions are doped in the second Bragg reflector 20. Since the number of Bragg reflector pairs in the second Bragg reflector 20 can be reduced, free carrier absorption introduced by the conductive ions in the second Bragg reflector 20 can be reduced.

[0031] In this embodiment, the plurality of active layers include the first active layer 5 to the Nth active layer sequentially arranged along the first direction Z, where N is an integer greater than or equal to 2. Exemplarily, the first direction Z is perpendicular to the surface of the first Bragg reflector 3 facing the active layer.

[0032] In this embodiment, the number of tunnel junctions is one or more, and the one or more tunnel junctions include the first tunnel junction 9 to the N-1th tunnel junction. Any n-1th tunnel junction is located between the n-1th active layer and the nth active layer, and n is an integer greater than or equal to 2 and less than or equal to N.

[0033] In this embodiment, the number of the current limiting layer is one or more, and the one or more current limiting layers include the first current limiting layer 7 to the Nth current limiting layer, and any n-1th current limiting layer is located between the n-1th active layer and the n-1th tunnel junction. The Nth current limiting layer is located between the Nth active layer and the second Bragg reflector 20.

[0034] The active layer, the current confinement layer and the tunnel junction are arranged in a first direction Z.

[0035] Any n-1th current limiting layer includes an n-1th light emitting region and an n-1th oxidation region surrounding the n-1th light emitting region. The Nth current limiting layer includes an Nth light emitting region and an Nth oxidation region surrounding the Nth light emitting region. The n-1th light emitting region and the Nth light emitting region are arranged opposite to each other in the first direction Z, and the n-1th oxidation region and the Nth oxidation region are arranged opposite to each other in the first direction Z.

[0036] The first microstructure area 22a has a projection on the first part of the n-1 light exit area along the first direction Z, the second microstructure area 22b has a projection on the second part of the n-1 light exit area along the first direction Z, and the second part of the n-1 light exit area surrounds the first part of the n-1 light exit area. The first microstructure area 22a has a projection on the first part of the N light exit area along the first direction Z, the second microstructure area 22b has a projection on the second part of the N light exit area along the first direction Z, and the second part of the N light exit area surrounds the first part of the N light exit area.

[0037] In some embodiments, the size of the light emitting area along the second direction is 4 microns to 9 microns. The size of the light emitting area along the second direction is larger, which improves the light output power. Exemplarily, the size of any n-1th light emitting area along the second direction is 4 microns to 9 microns; the size of the Nth light emitting area along the second direction is 4 microns to 9 microns.

[0038] In some embodiments, reference Figure 1 The first microstructure region 22a is a solid structure, and the second microstructure region 22b is a groove.

[0039] In other embodiments, the first microstructure area 22a is a first grating structure, and the second microstructure area 22b is a second grating structure. The first grating structure includes a first grating bar and a first grating slit. The second grating structure includes a second grating bar and a second grating slit. The grating period of the first grating structure is different from the grating period of the second grating structure. By setting the first grating structure and the second grating structure to have different grating periods, the reflectivity of the first grating structure and the reflectivity of the second grating structure are different. Exemplarily, the reflectivity of the second grating structure is less than the reflectivity of the first grating structure. The first grating structure and the second grating structure can also adjust the polarization characteristics of the output light.

[0040] In this embodiment, the high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: a semiconductor substrate layer 2 located on the side of the first Bragg reflector 3 away from the second Bragg reflector 20 ; and a back electrode layer 1 located on the side of the semiconductor substrate layer 2 away from the first Bragg reflector 3 .

[0041] In this embodiment, the high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: an ohmic contact layer 21 located between the modulation layer 22 and the second Bragg reflector 20 .

[0042] In this embodiment, the high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: a front electrode layer 23, located on the side of the modulation layer 22 along the second direction, and the front electrode layer 23 and the modulation layer 22 have overlapping projections in the second direction; wherein the second microstructure area 22b is located between the first microstructure area 22a and the front electrode layer 23; wherein the second direction is perpendicular to the first direction. The front electrode layer 23 and the oxidation area have overlapping projections in the first direction.

[0043] In other embodiments, the front electrode layer is located on the side of the modulation layer 22 away from the first Bragg reflector 3. The front electrode layer and the first microstructure area 22a have no overlapping projections in the first direction Z, and the front electrode layer and the second microstructure area 22b have no overlapping projections in the first direction Z. The front electrode layer and the oxidation area have overlapping projections in the first direction.

[0044] In one embodiment, the end of the front electrode layer on the side facing the modulation layer in the second direction is away from the modulation layer in the second direction relative to the end of the oxide zone on the side facing the modulation layer in the second direction. The size of the front electrode layer in the second direction is 60% to 80% of the size of the oxide zone in the second direction. The size of the front electrode layer in the second direction is less than 80% of the size of the oxide zone in the second direction, which reduces the absorption of light by the front electrode layer and further improves the power. The size of the front electrode layer in the second direction is greater than 60% of the size of the oxide zone in the second direction, so that the lateral conductive path is not too small, which helps to reduce resistance.

[0045] In this embodiment, the high-power and high-efficiency single-mode semiconductor light-emitting structure also includes: a first waveguide structure 4 to a 2Nth waveguide structure, the first waveguide structure 4 is located between the first Bragg reflector 3 and the first active layer 5, the 2Nth waveguide structure is located between the Nth active layer and the Nth current limiting layer, the 2n-2th waveguide structure is located between the n-1th active layer and the n-1th tunnel junction, the 2n-1th waveguide structure is located between the n-1th tunnel junction and the nth active layer, the 2n-2th waveguide structure includes a 2n-2th lower waveguide layer and a 2n-2th upper waveguide layer, the 2n-2th upper waveguide layer is located on the side of the 2n-2th lower waveguide layer away from the first Bragg reflector 3; the n-1th current limiting layer is located between the 2n-2th lower waveguide layer and the 2n-2th upper waveguide layer.

[0046] In this embodiment, when N is equal to 3, the high-power and high-efficiency single-mode semiconductor light-emitting structure includes: a first Bragg reflector 3; a first active layer 5, a second active layer 11 and a third active layer 17 arranged in sequence along the first direction Z on one side of the first Bragg reflector 3, the second active layer 11 is located on the side of the first active layer 5 away from the first Bragg reflector 3, and the third active layer 17 is located on the side of the second active layer 11 away from the first active layer 5; a first tunnel junction 9, the first tunnel junction 9 is located between the first active layer 5 and the second active layer 11; the second tunnel junction 15 is located between the second active layer 11 and the third active layer 17; the first current limiting layer 7 is located between the first active layer 5 and the first tunnel junction 9; the second current limiting layer 13 is located between the second active layer 11 and the second tunnel junction 15; the third current limiting layer 19 is located between the third active layer 17 and the second Bragg reflector 20. The high-power and high-efficiency single-mode semiconductor light-emitting structure also includes a first waveguide structure 4, a second waveguide structure, a third waveguide structure 10, a fourth waveguide structure, a fifth waveguide structure 16 and a sixth waveguide structure 18. The first waveguide structure 4 is located between the first Bragg reflector 3 and the first active layer 5. The sixth waveguide structure 18 is located between the third active layer 11 and the third current limiting layer 19. The second waveguide structure is located between the first active layer 5 and the first tunnel junction 9. The second waveguide structure includes a second lower waveguide layer 6 and a second upper waveguide layer 8. The second upper waveguide layer 8 is located on the side of the second lower waveguide layer 6 away from the first Bragg reflector 3. The first current limiting layer 7 is located between the second lower waveguide layer 6 and the second upper waveguide layer 8. The third waveguide structure 10 is located between the first tunnel junction 9 and the second active layer 9. The fourth waveguide structure is located between the second active layer 11 and the second tunnel junction 15, the fourth waveguide structure includes a fourth lower waveguide layer 12 and a fourth upper waveguide layer 14, the fourth upper waveguide layer 14 is located on the side of the fourth lower waveguide layer 12 away from the first Bragg reflector 3, the second current limiting layer 13 is located between the fourth lower waveguide layer 12 and the fourth upper waveguide layer 14, the fifth waveguide structure 16 is located between the second tunnel junction 15 and the third active layer 17; the semiconductor substrate layer 2 is located on the side of the first Bragg reflector 3 away from the second Bragg reflector 20; the back electrode layer 1 is located on the side of the semiconductor substrate layer 2 away from the first Bragg reflector 3; the ohmic contact layer 21 is located between the modulation layer 22 and the second Bragg reflector 20; the front electrode layer.

[0047] The first current limiting layer 7 includes a first light exiting area and a first oxidation area surrounding the first light exiting area, the second current limiting layer 13 includes a second light exiting area and a second oxidation area surrounding the second light exiting area, and the third current limiting layer 19 includes a third light exiting area and a third oxidation area surrounding the third light exiting area. The first light exiting area, the second light exiting area and the third light exiting area are relatively arranged in the first direction Z, and the first oxidation area, the second oxidation area and the third oxidation area are relatively arranged in the first direction Z. The first microstructure area 22a has a projection on a first part of the first light exiting area along the first direction Z, the second microstructure area 22b has a projection on a second part of the first light exiting area along the first direction Z, and the second part of the first light exiting area surrounds the first part of the first light exiting area. The first microstructure area 22a has a projection on a first part of the second light exiting area along the first direction Z, the second microstructure area 22b has a projection on a second part of the second light exiting area along the first direction Z, and the second part of the second light exiting area surrounds the first part of the second light exiting area. The first microstructure area 22a has a projection on the first part of the third light exit area along the first direction Z, the second microstructure area 22b has a projection on the second part of the third light exit area along the first direction Z, and the second part of the third light exit area surrounds the first part of the third light exit area.

[0048] It should be noted that Figure 1 In the example, N is equal to 3. In other embodiments, N may also select other values.

[0049] In one embodiment, the size of the first microstructure area 22a along the second direction is 20% to 35% of the size of the light exit area along the second direction; wherein the second direction is perpendicular to the first direction. Exemplarily, the size of the first microstructure area 22a along the second direction is 20% to 35% of the size of the first light exit area along the second direction, the size of the first microstructure area 22a along the second direction is 20% to 35% of the size of the second light exit area along the second direction, and the size of the first microstructure area 22a along the second direction is 20% to 35% of the size of the third light exit area along the second direction. If the size of the first microstructure area 22a along the second direction is less than 20%, the modulation area of ​​the first microstructure area 22a along the second direction is small, and the mode volume maintaining high gain is small, so that the degree of improvement of the single-mode output power is limited, and the degree of improvement of the efficiency is limited; if the size of the first microstructure area 22a along the second direction is greater than 35%, the high-order mode space part will obtain high gain, and it is difficult to maintain single-mode output at full current.

[0050] In one embodiment, the overall reflectivity range of the second Bragg reflector 20 and the modulation layer 22 has a lower limit value and an upper limit value, and the ratio of the difference between the upper limit value and the lower limit value to the upper limit value is greater than or equal to 25%.

[0051] In one embodiment, the thickness of the first microstructure region 22a of the modulation layer 22 in the first direction is 1 / 4 of the central wavelength of the light emitted by the high-power and high-efficiency single-mode semiconductor light-emitting structure.

[0052] In one embodiment, the material of the modulation layer 22 is a semiconductor material or an insulating dielectric material. In other embodiments, the modulation layer 22 is formed by material molding, and the material of the modulation layer has air holes, which are used to adjust the effective optical path of the output light in the modulation layer 22, so that the output light has a stronger adjustment effect and forms a stronger feedback in the cavity.

[0053] Exemplarily, when the first microstructure region 22a is a solid structure and the second microstructure region 22b is a groove, the material of the first microstructure region 22a has air holes. When the first microstructure region 22a is a first grating structure and the second microstructure region 22b is a second grating structure, the material of the first grating strips and the material of the second grating strips have air holes.

[0054] In other embodiments, the material of the modulation layer may not have air holes.

[0055] In one embodiment, when the second microstructure region 22b is a groove, the second microstructure region 22b penetrates the modulation layer 22 along the first direction Z. In other embodiments, when the second microstructure region 22b is a groove, the second microstructure region is located in a partial thickness of the modulation layer along the first direction.

[0056] Figure 2 Schematic diagram of the change in position of the reflectivity along the second direction obtained for the comparative example and the test example. Figure 2 The middle curve L1 is a schematic diagram of the change in the reflectivity of the second Bragg reflector in the semiconductor light emitting structure of the comparative example along the second direction. Figure 2 The middle curve L2 is a schematic diagram of the change in the reflectivity of the second Bragg reflector and the modulation layer in the semiconductor light emitting structure of the test example along the second direction. The reflectivity of the second Bragg reflector in the test example is less than or equal to 92%. The second Bragg reflector and the modulation layer in the test example can achieve a wider range of reflectivity modulation. Figure 2 The horizontal axis represents the optical thickness, and the vertical axis represents the reflectivity. Figure 2 In the figure, the horizontal axis of the test example represents the optical thickness of the second Bragg reflector and the modulation layer; the horizontal axis of the comparative example represents the optical thickness of the second Bragg reflector.

[0057] Another embodiment of the present invention also provides a method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure, comprising: forming a plurality of active layers, tunnel junctions, current limiting layers and second Bragg reflectors arranged along the first direction on one side of a first Bragg reflector along the first direction; the reflectivity of the first Bragg reflector is greater than the reflectivity of the second Bragg reflector; the active layer and the current limiting layer are both located between the first Bragg reflector and the second Bragg reflector, and the tunnel junction is located between adjacent active layers; wherein the current limiting layer includes a light emitting area and an oxidation area surrounding the light emitting area; a modulation layer is formed on the side of the second Bragg reflector away from the active layer, the modulation layer including a first microstructure area and a second microstructure area surrounding the first microstructure area, wherein the first microstructure area has a projection on a first part of the light emitting area along the first direction, the second microstructure area has a projection on a second part of the light emitting area along the first direction, and the second part surrounds the first part.

[0058] The step of forming the modulation layer includes: forming an initial modulation layer on a side of the second Bragg reflector away from the active layer; and etching the initial modulation layer to form the modulation layer.

[0059] This application can achieve the preparation of high-power and high-efficiency single-mode semiconductor light-emitting structures through conventional epitaxial growth without complicated processes, achieving single-mode, and greatly improving power and efficiency, truly realizing one-stop epitaxial growth to achieve ultra-high rate and high efficiency performance. This can greatly reduce the manufacturing difficulty and growth manufacturing cost.

[0060] In one embodiment, the method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure also includes: providing a semiconductor substrate layer 2; forming a first Bragg reflector 3 on one side of the semiconductor substrate layer 2 along a first direction; and forming a back electrode layer 1 on a surface of the semiconductor substrate layer 2 facing away from the first Bragg reflector 3.

[0061] In this embodiment, the method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure also includes: a first waveguide structure 4 to a 2Nth waveguide structure, the first waveguide structure 4 is located between the first Bragg reflector 3 and the first active layer 5, the 2Nth waveguide structure is located between the Nth active layer and the Nth current limiting layer, the 2n-2th waveguide structure is located between the n-1th active layer and the n-1th tunnel junction, the 2n-1th waveguide structure is located between the n-1th tunnel junction and the nth active layer, the 2n-2th waveguide structure includes a 2n-2th lower waveguide layer and a 2n-2th upper waveguide layer, the 2n-2th upper waveguide layer is located on the side of the 2n-2th lower waveguide layer away from the first Bragg reflector 3; the n-1th current limiting layer is located between the 2n-2th lower waveguide layer and the 2n-2th upper waveguide layer.

[0062] In this embodiment, the method for preparing the high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: forming an ohmic contact layer 21 , wherein the ohmic contact layer 21 is located between the modulation layer 22 and the second Bragg reflector 20 .

[0063] In this embodiment, the high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: forming a front electrode layer, and the position of the front electrode layer refers to the description of the above-mentioned embodiment.

[0064] The description of the first microstructure region and the second microstructure region refers to the description of the aforementioned embodiment.

[0065] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A high-power and high-efficiency single-mode semiconductor light-emitting structure, characterized in that: include: A first Bragg reflector and a second Bragg reflector arranged along a first direction, wherein a reflectivity of the first Bragg reflector is greater than a reflectivity of the second Bragg reflector; A plurality of active layers and a current limiting layer arranged along the first direction between the first Bragg reflector and the second Bragg reflector; wherein the current limiting layer comprises a light emitting region and an oxidation region surrounding the light emitting region; A tunnel junction located between adjacent active layers; A modulation layer is located on a side of the second Bragg reflector away from the active layer, the modulation layer comprising a first microstructure region and a second microstructure region surrounding the first microstructure region, wherein the first microstructure region has a projection on a first part of the light exit region along the first direction, the second microstructure region has a projection on a second part of the light exit region along the first direction, and the second part surrounds the first part.

2. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The size of the first microstructure area along the second direction is 20% to 35% of the size of the light exit area along the second direction; wherein the second direction is perpendicular to the first direction.

3. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The reflectivity of the second Bragg reflector is less than or equal to 92%.

4. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The overall reflectivity range of the second Bragg reflector and the modulation layer has a lower limit value and an upper limit value, and a ratio of a difference between the upper limit value and the lower limit value to the upper limit value is greater than or equal to 25%.

5. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The thickness of the first microstructure region of the modulation layer in the first direction is 1 / 4 of the central wavelength of the light emitted by the high-power and high-efficiency single-mode semiconductor light-emitting structure.

6. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The material of the modulation layer is a semiconductor material or an insulating dielectric material.

7. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The first microstructure region is a solid structure, and the second microstructure region is a groove; or, the first microstructure region is a first grating structure, and the second microstructure region is a second grating structure, and the first grating structure and the second grating structure have different grating periods.

8. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: Also includes: The ohmic contact layer is located between the modulation layer and the second Bragg reflector.

9. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: Also includes: A front electrode layer is located on the side of the modulation layer along the second direction, and the front electrode layer and the modulation layer have overlapping projections in the second direction; wherein the second microstructure area is located between the first microstructure area and the front electrode layer; wherein the second direction is perpendicular to the first direction.

10. A method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure, characterized in that: include: Forming a plurality of active layers, tunnel junctions, current confinement layers and a second Bragg reflector arranged along the first direction on one side of the first Bragg reflector along the first direction; The reflectivity of the first Bragg reflector is greater than the reflectivity of the second Bragg reflector; The active layer and the current limiting layer are both located between the first Bragg reflector and the second Bragg reflector, and the tunnel junction is located between adjacent active layers; wherein the current limiting layer includes a light emitting region and an oxidized region surrounding the light emitting region; A modulation layer is formed on the side of the second Bragg reflector facing away from the active layer, and the modulation layer includes a first microstructure area and a second microstructure area surrounding the first microstructure area, wherein the first microstructure area has a projection on a first part of the light exit area along the first direction, and the second microstructure area has a projection on a second part of the light exit area along the first direction, and the second part surrounds the first part.

11. The method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 10, characterized in that: The step of forming the modulation layer includes: forming an initial modulation layer on a side of the second Bragg reflector away from the active layer; and etching the initial modulation layer to form the modulation layer.

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