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

Abstract

The present 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 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; the current limiting layer comprises a light emitting region and an oxidation region surrounding the light emitting region; a tunnel junction is located between adjacent active layers; a modulation layer is located on a side of the second Bragg reflector away from the active layer, and 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, and 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 particularly 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 applications of high-power multi-transverse-mode vertical-cavity surface-emitting lasers (VCSELs) have developed rapidly. They have been widely used in fields such as 3D face recognition, autonomous driving, and high-bit-rate data communication. Certain improvements have been made in terms of the power and efficiency of multi-transverse-mode vertical-cavity surface-emitting lasers. 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 their 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 relatively low precision requirements. Especially in the field of high-speed communication, with the adoption of the four-level pulse amplitude modulation PAM4 (4-Level Pulse Amplitude Modulation) scheme, the importance of power has become even more prominent. Therefore, developing high-power single-transverse-mode vertical-cavity surface-emitting lasers is of crucial significance.

[0003] Since 2005, the output power of single-transverse-mode vertical-cavity surface-emitting lasers has been stable in the range of 6 mW to 8 mW. Until 2021, a single-transverse-mode vertical-cavity surface-emitting laser with a laser output of 10 mW was achieved through an improved zinc diffusion process, but its electro-optical conversion efficiency was still very low, only about 12%. It should be particularly emphasized that the realization of high efficiency 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 total 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 neuromorphic photonic computing and vertical-cavity surface-emitting laser-based deep learning fields. 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 further includes: a front electrode layer located on the side of the modulation layer along the second direction, and the front electrode layer and the modulation layer have an overlapping projection in the second direction; wherein, the second microstructural region is located between the first microstructural region and the front electrode layer; wherein, the second direction is perpendicular to the first direction.

[0014] The present application also provides a method for manufacturing a high-power and high-efficiency single-mode semiconductor light-emitting structure, including: 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 that of the second Bragg reflector; both the active layer and the current confinement layer are located between the first Bragg reflector and the second Bragg reflector, and the tunnel junction is located between adjacent active layers; wherein, the current confinement layer includes a light-emitting region and an oxidized region surrounding the light-emitting region; forming a modulation layer on the side of the second Bragg reflector facing away from the active layer, the modulation layer including a first microstructural region and a second microstructural region surrounding the first microstructural region, wherein, the first microstructural region has a projection on a first part of the light-emitting region along the first direction, and the second microstructural 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 the side of the second Bragg reflector facing away from the active layer; etching the initial modulation layer to form the modulation layer.

[0016] The technical solution of the present invention has the following beneficial effects:

[0017] For the high-power and high-efficiency single-mode semiconductor light-emitting structure provided by the technical solution of the present invention, multiple active layers are cascaded through tunnel junctions, which can achieve higher gain in the cavity, thereby enabling higher power output. Introducing the modulation layer will reduce the proportion of intracavity loss, thereby achieving efficiency improvement. Higher gain can support maintaining a low threshold current when the second Bragg reflector has a low reflectivity. In addition, due to the setting of the modulation layer, the range of the overall reflectivity of the second Bragg reflector and the modulation layer is increased, realizing a larger range of reflectivity modulation. Since the second Bragg reflector has a low reflectivity and the overall reflectivity of the second Bragg reflector and the modulation layer realizes a larger range of reflectivity modulation, the modulation ability of the modulation layer on the intracavity optical field can be enhanced, thereby realizing the gain difference between modes, and thus realizing higher-power single-mode power output. In addition, due to the setting of the modulation layer to achieve a larger range of reflectivity modulation, more light is emitted, further improving the power. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 Schematic diagram of a high-power and high-efficiency single-mode semiconductor light-emitting structure according to an embodiment of the present application;

[0020] Figure 2 Schematic diagram of the change of the reflectivity along the position in the second direction obtained in the comparative example and the test example. Specific embodiments

[0021] It has been found through research that the reasons for the limited power and efficiency of single-mode vertical-cavity surface-emitting lasers come from multiple key factors. First of all, as a kind of microcavity laser, the gain volume of the vertical-cavity surface-emitting laser along the light-emitting direction is very small, resulting in a 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 restricted, and usually the aperture of the light-emitting area is 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, which further exacerbates the self-heating effect of the vertical-cavity surface-emitting laser. The self-heating effect further limits the upper limit of its drive current and hinders the possibility of achieving high-power single-transverse-mode laser output. To obtain high-power single-transverse-mode laser output, various 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 when the aperture of the light-emitting area is increased, the threshold gain difference of its transverse modes continuously decreases, 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 high-order mode and the fundamental transverse mode through technical means while expanding the aperture of the light-emitting area. Various techniques have been adopted, such as zinc diffusion, high-contrast gratings, surface relief, triangular hole structures, photonic crystals, and anti-waveguide cavities, to adjust the threshold gain difference between the fundamental transverse mode and the high-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 design of single-junction vertical-cavity surface-emitting lasers is usually very high, up to more than 98%, making it difficult for these methods to effectively regulate the intracavity modes, resulting in a limited single-mode operating range. In short, the increase in the lateral gain area is limited, and the suppression ratio between the fundamental mode and the high-order mode is insufficient, making it difficult to significantly improve the power. Secondly, the reflectivity of the top Bragg reflector used in the design of vertical-cavity surface-emitting lasers usually exceeds 98%, and a very high number of Bragg reflector pairs are required to achieve this reflectivity. However, this design significantly increases the series resistance, resulting in an enhanced Joule heating effect. The doped Bragg reflector also introduces free-carrier absorption, and the introduced microstructures increase the internal loss, making it difficult for single-mode vertical-cavity surface-emitting lasers to achieve high efficiency. 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 results in a weak coupling between the surface structure and the oscillation in the laser cavity, limiting the ability of the microstructure to regulate the optical mode.

[0022] On this basis, the embodiment of the present application provides a high-power and high-efficiency single-mode semiconductor light-emitting structure, and the power and efficiency of the single-mode semiconductor light-emitting structure are effectively improved.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] An embodiment of the present invention provides a high-power and high-efficiency single-mode semiconductor light-emitting structure, referring to Figure 1 ,include:

[0027] 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;

[0028] 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;

[0029] A tunnel junction located between adjacent active layers;

[0030] 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.

[0031] In the high-power and high-efficiency single-mode semiconductor light-emitting structure according to the embodiment of the present application, multiple active layers are cascaded through tunnel junctions, which can achieve higher gain in the cavity, thereby enabling higher power output. Introducing the modulation layer 22 reduces the proportion of cavity loss, thus achieving efficiency improvement. Higher gain can support maintaining a low threshold current even when the second Bragg reflector 20 has a low reflectivity. Additionally, due to the setting of the modulation layer, the overall reflectivity range of the second Bragg reflector 20 and the modulation layer 22 increases, achieving a larger range of reflectivity modulation. Since the second Bragg reflector 20 has a low reflectivity and the overall of the second Bragg reflector 20 and the modulation layer 22 achieves a larger range of reflectivity modulation, the modulation ability of the modulation layer 22 on the intracavity optical field can be enhanced, thereby achieving a gain difference between modes, and thus achieving higher-power single-mode power output. Additionally, due to the setting of the modulation layer 22 to achieve a larger range of reflectivity modulation, more light is emitted, further increasing the power.

[0032] In addition, with higher power output, the operating current can be significantly reduced, thereby improving reliability and extending the lifespan.

[0033] 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.

[0034] In this embodiment, the reflectivity of the second Bragg reflector 20 is less than or equal to 92%, for example, 70% - 92%.

[0035] In this embodiment, the reflectivity of the second Bragg reflector 20 is less than that of the second Bragg reflector used in the prior art. The reflectivity of the second Bragg reflector 20 is relatively small, 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.

[0036] In some embodiments, the second Bragg reflector 20 is doped with conductive ions. Since the number of Bragg reflector pairs in the second Bragg reflector 20 can be reduced, the free carrier absorption introduced by the conductive ions in the second Bragg reflector 20 can be reduced.

[0037] In this embodiment, the multiple active layers include a first active layer 5 to an Nth active layer arranged in sequence 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 side.

[0038] In this embodiment, the number of tunnel junctions is one or more. The one or more tunnel junctions include a first tunnel junction 9 to an (N - 1)th tunnel junction. Any (n - 1)th tunnel junction is located between an (n - 1)th active layer and an nth active layer, where n is an integer greater than or equal to 2 and less than or equal to N.

[0039] In this embodiment, the number of current confinement layers is one or more. The one or more current confinement layers include a first current confinement layer 7 to an Nth current confinement layer. Any (n - 1)th current confinement layer is located between an (n - 1)th active layer and an (n - 1)th tunnel junction. The Nth current confinement layer is located between an Nth active layer and a second Bragg reflector 20.

[0040] The active layers, current confinement layers, and tunnel junctions are arranged in the first direction Z.

[0041] Any (n - 1)th current confinement layer includes an (n - 1)th light-emitting region and an (n - 1)th oxidation region surrounding the (n - 1)th light-emitting region. The Nth current confinement layer includes an Nth light-emitting region and an Nth oxidation region surrounding the Nth light-emitting region. The (n - 1)th light-emitting region and the Nth light-emitting region are oppositely arranged in the first direction Z, and the (n - 1)th oxidation region and the Nth oxidation region are oppositely arranged in the first direction Z.

[0042] The first microstructure region 22a has a projection on a first part of the (n - 1)th light-emitting region along the first direction Z, and the second microstructure region 22b has a projection on a second part of the (n - 1)th light-emitting region along the first direction Z. The second part of the (n - 1)th light-emitting region surrounds the first part of the (n - 1)th light-emitting region. The first microstructure region 22a has a projection on a first part of the Nth light-emitting region along the first direction Z, and the second microstructure region 22b has a projection on a second part of the Nth light-emitting region along the first direction Z. The second part of the Nth light-emitting region surrounds the first part of the Nth light-emitting region.

[0043] In some embodiments, the size of the light-emitting region in the second direction is 4 μm - 9 μm. The relatively large size of the light-emitting region in the second direction increases the light output power. Exemplarily, the size of any (n - 1)th light-emitting region in the second direction is 4 μm - 9 μm; the size of the Nth light-emitting region in the second direction is 4 μm - 9 μm.

[0044] In some embodiments, referring to Figure 1 , the first microstructure region 22a is a solid structure, and the second microstructure region 22b is a groove.

[0045] In other embodiments, the first microstructure region 22a is a first grating structure, and the second microstructure region 22b is a second grating structure. The first grating structure includes first grating bars and first grating slits. The second grating structure includes second grating bars and second grating slits. The grating period of the first grating structure is different from that of the second grating structure. By setting the first grating structure and the second grating structure to have different grating periods, the reflectivities of the first grating structure and the second grating structure are made different. Exemplarily, the reflectivity of the second grating structure is less than that of the first grating structure. The first grating structure and the second grating structure can also adjust the polarization characteristics of the emitted light.

[0046] 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; a back electrode layer 1 located on the side of the semiconductor substrate layer 2 away from the first Bragg reflector 3.

[0047] 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.

[0048] 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 an overlapping projection in the second direction; wherein, the second microstructure region 22b is located between the first microstructure region 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 region have an overlapping projection in the first direction.

[0049] In other embodiments, the front electrode layer is located on the side of the modulation layer 22 away from the first Bragg reflector 3. And the front electrode layer and the first microstructure region 22a have no overlapping projection in the first direction Z, and the front electrode layer and the second microstructure region 22b have no overlapping projection in the first direction Z. The front electrode layer and the oxidation region have an overlapping projection in the first direction.

[0050] In one embodiment, the end of the front electrode layer facing the modulation layer in the second direction is farther away from the modulation layer in the second direction than the end of the oxidation region facing the modulation layer in the second direction. The size of the front electrode layer in the second direction is 60% - 80% of the size of the oxidation region in the second direction. The size of the front electrode layer in the second direction is less than 80% of the size of the oxidation region in the second direction, which reduces the light absorption of 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 oxidation region in the second direction, which makes the lateral conduction path not too small and helps to reduce the resistance.

[0051] In this embodiment, the high-power and high-efficiency single-mode semiconductor light-emitting structure further 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 confinement layer. The (2n - 2)th waveguide structure is located between the (n - 1)th active layer and the (n - 1)th tunnel junction. The (2n - 1)th waveguide structure is located between the (n - 1)th tunnel junction and the nth active layer. The (2n - 2)th waveguide structure includes a (2n - 2)th lower waveguide layer and a (2n - 2)th upper waveguide layer. The (2n - 2)th upper waveguide layer is located on the side of the (2n - 2)th lower waveguide layer away from the first Bragg reflector 3. The (n - 1)th current confinement layer is located between the (2n - 2)th lower waveguide layer and the (2n - 2)th upper waveguide layer.

[0052] 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.

[0053] The first current limiting layer 7 includes a first light emitting region and a first oxidation region surrounding the first light emitting region. The second current limiting layer 13 includes a second light emitting region and a second oxidation region surrounding the second light emitting region. The third current limiting layer 19 includes a third light emitting region and a third oxidation region surrounding the third light emitting region. The first light emitting region, the second light emitting region, and the third light emitting region are oppositely arranged in the first direction Z. The first oxidation region, the second oxidation region, and the third oxidation region are oppositely arranged in the first direction Z. The first microstructure region 22a has a projection on a first part of the first light emitting region along the first direction Z. The second microstructure region 22b has a projection on a second part of the first light emitting region along the first direction Z. The second part of the first light emitting region surrounds the first part of the first light emitting region. The first microstructure region 22a has a projection on a first part of the second light emitting region along the first direction Z. The second microstructure region 22b has a projection on a second part of the second light emitting region along the first direction Z. The second part of the second light emitting region surrounds the first part of the second light emitting region. The first microstructure region 22a has a projection on a first part of the third light emitting region along the first direction Z. The second microstructure region 22b has a projection on a second part of the third light emitting region along the first direction Z. The second part of the third light emitting region surrounds the first part of the third light emitting region.

[0054] It should be noted that Figure 1 in the example, N is equal to 3. In other embodiments, N can also be selected as other values.

[0055] In one embodiment, the size of the first microstructure region 22a in the second direction is 20% - 35% of the size of the light emitting region in the second direction; wherein, the second direction is perpendicular to the first direction. Exemplarily, the size of the first microstructure region 22a in the second direction is 20% - 35% of the size of the first light emitting region in the second direction, the size of the first microstructure region 22a in the second direction is 20% - 35% of the size of the second light emitting region in the second direction, and the size of the first microstructure region 22a in the second direction is 20% - 35% of the size of the third light emitting region in the second direction. If the size of the first microstructure region 22a in the second direction is less than 20%, the modulation area of the first microstructure region 22a in the second direction is small, the mode volume for maintaining high gain is small, so that the degree of improvement in the single-mode output power is limited, and the degree of efficiency improvement is limited; if the size of the first microstructure region 22a in the second direction is greater than 35%, it will cause the high-order mode spatial part to obtain high gain, and it is difficult to maintain single-mode output under full current.

[0056] 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%.

[0057] In one embodiment, the thickness of the first microstructural 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.

[0058] 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 a material shaping method, and the material of the modulation layer has air holes, and the air holes are used to adjust the effective optical path of the output light in the modulation layer 22, so as to have a stronger adjustment effect on the output light and form a stronger feedback in the cavity.

[0059] Exemplarily, when the first microstructural region 22a is a solid structure and the second microstructural region 22b is a groove, the material of the first microstructural region 22a has air holes. When the first microstructural region 22a is a first grating structure and the second microstructural region 22b is a second grating structure, the material of the first grating bar and the material of the second grating bar have air holes.

[0060] In other embodiments, the material of the modulation layer may not have air holes.

[0061] In one embodiment, when the second microstructural region 22b is a groove, the second microstructural region 22b penetrates through the modulation layer 22 along the first direction Z. In other embodiments, when the second microstructural region 22b is a groove, the second microstructural region is located in a modulation layer with a partial thickness along the first direction.

[0062] Figure 2 Schematic diagram of the change of the reflectivity obtained for the comparative example and the test example along the position in the second direction. Figure 2 In the figure, curve L1 is a schematic diagram of the change of the reflectivity of the second Bragg reflector in the semiconductor light-emitting structure of the comparative example along the position in the second direction. Figure 2 In the figure, curve L2 is a schematic diagram of the change of the overall reflectivity of the second Bragg reflector and the modulation layer in the semiconductor light-emitting structure of the test example along the position in the second direction. The reflectivity of the second Bragg reflector in the test example is less than or equal to 92%. The overall of the second Bragg reflector and the modulation layer in the test example can achieve a larger range of reflectivity modulation. Figure 2 In the figure, the horizontal axis represents the optical thickness, and the vertical axis represents the reflectivity. Figure 2 In the figure, for the test example, the horizontal axis represents the optical thickness of the second Bragg reflector and the modulation layer; for the comparative example, the horizontal axis represents the optical thickness of the second Bragg reflector.

[0063] Another embodiment of the present invention further provides a method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure, including: 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 that of the second Bragg reflector; both the active layer and the current confinement layer are located between the first Bragg reflector and the second Bragg reflector, and the tunnel junction is located between adjacent active layers; wherein, the current confinement layer includes a light-emitting region and an oxidized region surrounding the light-emitting region; forming a modulation layer on the side of the second Bragg reflector facing away from the active layer, the modulation layer includes 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, and 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.

[0064] The step of forming the modulation layer includes: forming an initial modulation layer on the side of the second Bragg reflector facing away from the active layer; etching the initial modulation layer to form the modulation layer.

[0065] Through conventional epitaxial growth, the present application can achieve the preparation of a high-power and high-efficiency single-mode semiconductor light-emitting structure without complex processes, realize single-mode, as well as a great improvement in power and efficiency, and truly achieve the performance of ultra-high speed and high efficiency with one-stop epitaxial growth. This can greatly reduce the manufacturing difficulty and growth manufacturing cost.

[0066] In one embodiment, the method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: providing a semiconductor substrate layer 2; forming a first Bragg reflector 3 on one side of the semiconductor substrate layer 2 along the first direction; forming a back electrode layer 1 on the surface of the semiconductor substrate layer 2 on the side facing away from the first Bragg reflector 3.

[0067] In this embodiment, the method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure further 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 confinement layer, the (2n - 2)th waveguide structure is located between the (n - 1)th active layer and the (n - 1)th tunnel junction, the (2n - 1)th waveguide structure is located between the (n - 1)th tunnel junction and the nth active layer, the (2n - 2)th waveguide structure includes a (2n - 2)th lower waveguide layer and a (2n - 2)th upper waveguide layer, and the (2n - 2)th upper waveguide layer is located on the side of the (2n - 2)th lower waveguide layer facing away from the first Bragg reflector 3; the (n - 1)th current confinement layer is located between the (2n - 2)th lower waveguide layer and the (2n - 2)th upper waveguide layer.

[0068] In this embodiment, the method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure further includes: forming an ohmic contact layer 21, where the ohmic contact layer 21 is located between the modulation layer 22 and the second Bragg reflector 20.

[0069] 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 foregoing embodiment.

[0070] The descriptions of the first microstructure region and the second microstructure region refer to the description of the foregoing embodiment.

[0071] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom still fall within the protection scope of the present 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, and a reflectivity of the second Bragg reflector is less than or equal to 92%; 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, 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; a size of the first microstructure region along the second direction is 20% to 35% of a size of the light exit region along the second direction; wherein the second direction is perpendicular to the first direction; 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%; The first microstructure region is a first grating structure, the second microstructure region is a second grating structure, and the first grating structure and the second grating structure have different grating periods; Alternatively, the first microstructure area is a solid structure, and the second microstructure area is a groove; wherein the semiconductor light-emitting structure also includes a front electrode layer located on the side of the modulation layer along the second direction, and the groove is located between the first microstructure area and the front electrode layer, and the second direction is perpendicular to the first direction, or the groove extends in the modulation layer along the first direction.

2. 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.

3. 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.

4. 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.

5. The high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 1, characterized in that: The front electrode layer is located at a 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.

6. 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, and the reflectivity of the second Bragg reflector is less than or equal to 92%; 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 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; the size of the first microstructure region along the second direction is 20% to 35% of the size of the light exit region along the second direction; wherein the second direction is perpendicular to the first direction; 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%; The first microstructure region is a first grating structure, the second microstructure region is a second grating structure, and the first grating structure and the second grating structure have different grating periods; Alternatively, the first microstructure area is a solid structure, and the second microstructure area is a groove; wherein the semiconductor light-emitting structure also includes a front electrode layer located on the side of the modulation layer along the second direction, and the groove is located between the first microstructure area and the front electrode layer, and the second direction is perpendicular to the first direction, or the groove extends in the modulation layer along the first direction.

7. The method for preparing a high-power and high-efficiency single-mode semiconductor light-emitting structure according to claim 6, 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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