Light-emitting device and projector

Abstract

To provide a light-emitting device capable of reducing scattering due to a second photonic crystal oscillated by a first photonic crystal.SOLUTION: A light-emitting device includes: a first semiconductor layer that includes a first conductive type; a second semiconductor layer that includes a second conductive type that is different from the first conductive type; a light emission layer that is provided between the first semiconductor layer and the second semiconductor layer; and a photonic crystal layer that is provided to the side opposite to the light emission layer of the second semiconductor layer. The photonic crystal layer includes: a first region that oscillates a light emitted by the light emission layer to a direction orthogonal to a lamination direction of the first semiconductor layer and the light emission layer, and in which a first photonic crystal that does not radiate the light to a direction different from an orthogonal direction is provided; and a second region which is not overlapped with the first region with respect to the lamination direction, and in which a second photonic crystal that radiates a light emitted by the light emission layer to the direction different from the direction orthogonal is provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light emitting device and a projector. [Background technology]

[0002] Photonic Crystal Surface Emitting Laser (PCEL) A known laser is a PCSEL (Plasma-Crystalline Surface Emitting Laser).

[0003] For example, Patent Document 1 describes a PCSEL in which a distributed feedback control photonic crystal and a surface emission control photonic crystal are superimposed. The distributed feedback control photonic crystal is configured so that light propagating with the active layer as a core is two-dimensionally distributed and fed back within the plane of the active layer and is not emitted in a direction perpendicular to the active layer. The surface emission control photonic crystal is configured so that propagating light is emitted in a direction perpendicular to the active layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-208127 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the PCSEL described in Patent Document 1, the holes forming the surface-emission control photonic crystal are arranged between adjacent holes forming the distributed feedback control photonic crystal, and as a result, the light that is distributed and fed back by the distributed feedback control photonic crystal is scattered by the holes that make up the surface-emission control photonic crystal, resulting in loss. [Means for solving the problem]

[0006] One aspect of the light emitting device according to the present invention is a first semiconductor layer having a first conductivity type; a second semiconductor layer having a second conductivity type different from the first conductivity type; a light emitting layer provided between the first semiconductor layer and the second semiconductor layer; a photonic crystal layer provided on the second semiconductor layer opposite to the light emitting layer; having The photonic crystal layer comprises: a first region provided with a first photonic crystal that resonates the light emitted from the light emitting layer in a direction perpendicular to a stacking direction of the first semiconductor layer and the light emitting layer and does not emit the light in a direction different from the perpendicular direction; a second region in which a second photonic crystal is provided, the second region not overlapping with the first region as viewed from the stacking direction and configured to emit light emitted from the light emitting layer in a direction different from the orthogonal direction; has.

[0007] One aspect of the projector according to the present invention is The present invention has one aspect of the light emitting device. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view illustrating a light emitting device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention. [Diagram 3] 5A to 5C are cross-sectional views each showing a schematic process for manufacturing the light emitting device according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view illustrating a light emitting device according to a first modified example of the embodiment. [Diagram 5] FIG. 11 is a plan view diagrammatically illustrating a light emitting device according to a second modified example of the embodiment. [Figure 6] FIG. 11 is a plan view diagrammatically illustrating a light emitting device according to a third modified example of the embodiment. [Figure 7] FIG. 11 is a plan view diagrammatically illustrating a light emitting device according to a third modified example of the embodiment. [Figure 8] FIG. 1 is a diagram illustrating a projector according to an embodiment of the present invention. [Figure 9]FIG. 11 is a diagram illustrating a projector according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are necessarily essential components of the present invention.

[0010] 1. Light-emitting device Configuration First, the light emitting device according to the present embodiment will be described with reference to the drawings. Fig. 1 is a plan view showing a light emitting device 100 according to the present embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1 showing a light emitting device 100 according to the present embodiment. In Figs. 1 and 2, an X-axis, a Y-axis, and a Z-axis are shown as three mutually orthogonal axes.

[0011] 1 and 2, the light emitting device 100 includes, for example, a substrate 10, a first semiconductor layer 20, a light emitting layer 30, a second semiconductor layer 40, a photonic crystal layer 50, a third semiconductor layer 60, a contact layer 70, a first electrode 80, and a second electrode 82. The light emitting device 100 is a PCSEL. For convenience, components other than the photonic crystal layer 50 are not shown in FIG. 1.

[0012] The substrate 10 has, for example, a first conductivity type. The first conductivity type is, for example, an n-type. The substrate 10 is, for example, an n-type GaAs substrate doped with Si.

[0013] The first semiconductor layer 20 is provided on the substrate 10 as shown in FIG. 2. The first semiconductor layer 20 is provided between the substrate 10 and the light emitting layer 30. The first semiconductor layer 20 has, for example, an n-type conductivity. The first semiconductor layer 20 is, for example, a DBR (Distributed Bragg Reflector) in which a high refractive index layer and a low refractive index layer having a refractive index lower than that of the high refractive index layer are alternately laminated. The high refractive index layer is, for example, an n-type Al doped with Si. 0.1 Ga 0.9 The low refractive index layer is, for example, an n-type Al doped with Si. 0.9 Ga 0.1 The first semiconductor layer 20 is an As layer. The number of high refractive index layers and low refractive index layers is not particularly limited. The first semiconductor layer 20 reflects the light generated in the light emitting layer 30 toward the contact layer 70 side.

[0014] In this specification, in the stacking direction (hereinafter also simply referred to as "stacking direction") between the first semiconductor layer 20 and the light emitting layer 30, when the light emitting layer 30 is used as a reference, the direction from the light emitting layer 30 toward the second semiconductor layer 40 is described as "upper", and the direction from the light emitting layer 30 toward the first semiconductor layer 20 is described as "lower". In the illustrated example, the stacking direction is the Z-axis direction. Also, the direction perpendicular to the stacking direction is also referred to as the "in-plane direction".

[0015] The light emitting layer 30 is provided on the first semiconductor layer 20. The light emitting layer 30 is provided between the first semiconductor layer 20 and the second semiconductor layer 40. The light emitting layer 30 generates light when a current is injected into it. The light emitting layer 30 has, for example, a well layer and a barrier layer. The well layer and the barrier layer are i-type semiconductor layers that are not intentionally doped with impurities. The well layer is, for example, a GaAs layer or an InGaAs layer. The barrier layer is, for example, an AlGaAs layer (e.g., Al x Ga 1-x The light emitting layer 30 has a MQW (Multiple Quantum Well) structure composed of a well layer and a barrier layer. There are.

[0016] The number of well layers and barrier layers constituting the light-emitting layer 30 is not particularly limited. For example, only one well layer may be provided. In this case, the light-emitting layer 30 has a SQW (Single Quantum Well) structure.

[0017] The second semiconductor layer 40 is provided on the light emitting layer 30. The second semiconductor layer 40 is provided between the light emitting layer 30 and the photonic crystal layer 50. The second semiconductor layer 40 has a second conductivity type different from the first conductivity type. The second conductivity type is, for example, p-type. The second semiconductor layer 40 is, for example, a p-type AlGaAs layer (e.g., Al 0.5 Ga 0.5 As layer).

[0018] The photonic crystal layer 50 is provided on the second semiconductor layer 40. The photonic crystal layer 50 is provided on the side of the second semiconductor layer 40 opposite to the light emitting layer 30. The photonic crystal layer 50 is provided between the second semiconductor layer 40 and the third semiconductor layer 60. The photonic crystal layer 50 is composed of a semiconductor layer and a first hole 53 and a second hole 55 formed in the semiconductor layer. The semiconductor layer is, for example, a p-type GaAs layer doped with C. The first hole 53 and the second hole 55 may be vacant holes or may be filled with, for example, p-type InGaP.

[0019] The photonic crystal layer 50 has a first region 50a in which a first photonic crystal 52 is provided, and a second region 50b in which a second photonic crystal 54 is provided. As shown in Fig. 1, the first region 50a surrounds the second region 50b when viewed from the stacking direction. The second region 50b does not overlap with the first region 50a when viewed from the stacking direction. In the illustrated example, the second region 50b is square.

[0020] When viewed from the stacking direction, the first photonic crystal 52 surrounds the second photonic crystal 54. The first photonic crystal 52 has a plurality of periodically arranged first holes 53. The first photonic crystal 52 is composed of the plurality of first holes 53 and a semiconductor layer between adjacent first holes 53.

[0021] The first holes 53 of the first photonic crystal 52 have, for example, rotational symmetry when viewed from the stacking direction. In the illustrated example, the shape of the first holes 53 is a circle. The multiple first holes 53 are arranged, for example, in a square lattice pattern in the X-axis direction and the Y-axis direction. The basic shape F1 of the multiple first holes 53 forming the first photonic crystal 52 has, for example, rotational symmetry. In the illustrated example, the shape F1 is composed of four circles (2×2 periods).

[0022] The first photonic crystal 52 resonates the light generated in the light emitting layer 30 in the in-plane direction. The first photonic crystal 52 performs distributed feedback (diffracts in the in-plane direction) of the light generated in the light emitting layer 30 using odd-order diffraction, preferably first-order diffraction. By performing distributed feedback using first-order diffraction, the first photonic crystal 52 can confine the light propagating in the in-plane direction more strongly within the plane. Therefore, even if the distance D1 between the first hole 53 and the light emitting layer 30 is increased, the light generated in the light emitting layer 30 can be resonated in the in-plane direction. By increasing the distance D1, the reliability of the light emitting layer 30 can be improved. The distance D1 is, for example, 50 nm or more and 500 nm or less, preferably 100 nm or more and 300 nm or less. By performing distributed feedback using first-order diffraction, firstly, light loss due to diffraction out of the plane does not occur, so that out-of-plane light loss is reduced. Secondly, at the refractive index interfaces constituting the photonic crystal 52, specifically, for example, at the surface where light propagating in the +X-axis direction enters any one of the first holes 53 and the surface where the light passes through that surface and exits from the first hole 53, it is possible to prevent the cancellation of the light components reflected in the -X-axis direction.

[0023] The first photonic crystal 52 uses odd-order diffraction for distributed feedback, and therefore does not diffract the light generated in the light emitting layer 30 in a direction perpendicular to the in-plane direction. The first photonic crystal 52 does not diffract the light generated in the light emitting layer 30 in the stacking direction.

[0024] The second photonic crystal 54 has a plurality of second holes 55 that are periodically arranged. The second photonic crystal 54 is composed of a plurality of second holes 55 and a semiconductor layer between adjacent second holes 55. When viewed from the stacking direction, the shape of the first holes 53 and the shape of the second holes 55 are different.

[0025] The second holes 55 of the second photonic crystal 54 do not have, for example, rotational symmetry when viewed from the stacking direction. In the illustrated example, the shape of the second holes 55 is a right-angled isosceles triangle. The second holes 55 have an inclined surface 56 inclined at 45° with respect to the X-axis and the Y-axis. The multiple second holes 55 are arranged in a square lattice pattern, for example. The basic shape F2 of the multiple second holes 55 forming the second photonic crystal 54 does not have, for example, rotational symmetry. In the illustrated example, the shape F1 is composed of four right-angled isosceles triangles (2×2 period). The pitch of the multiple second holes 55 is different from the pitch of the multiple first holes 53. In the illustrated example, the pitch of the multiple second holes 55 is larger than the pitch of the multiple first holes 53.

[0026] The "hole pitch" is the distance between the centers of adjacent holes in a given direction. If the planar shape of the hole is a circle, the "center of the hole" is the center of the circle, and if the planar shape of the hole is not a circle, the center of the smallest inclusive circle. For example, if the planar shape of the hole is a polygon, the center of the hole is the center of the smallest circle that contains the polygon, and if the planar shape of the hole is an ellipse, the center of the smallest circle that contains the ellipse.

[0027] The second photonic crystal 54 can emit the light generated in the light emitting layer 30 in a direction different from the in-plane direction. For example, the second photonic crystal 54 emits the light generated in the light emitting layer 30 in the stacking direction. The second photonic crystal 54 emits the light generated in the light emitting layer 30 in the stacking direction, for example, by using first-order diffraction. Note that the second photonic crystal 54 may emit the light generated in the light emitting layer 30 in a direction oblique to the stacking direction, for example, by using third-order diffraction. The second photonic crystal 54 may also diffract the light generated in the light emitting layer 30 in the in-plane direction.

[0028] 2, the distance D2 between the second hole 55 of the second photonic crystal 54 and the light emitting layer 30 is, for example, greater than the distance D1 between the first hole 53 of the first photonic crystal 52 and the light emitting layer 30. This makes it possible to maintain the reliability of the portion of the light emitting layer 30 that overlaps with the second photonic crystal 54. Specifically, for example, it is possible to suppress the occurrence of dislocations in this region and the dislocations from reaching the light emitting layer 30 over time.

[0029] Although not shown, the distance D1 may be smaller than the distance D2. This makes it possible to increase the intensity of the light emitted in the stacking direction while maintaining the reliability of the portion of the light emitting layer 30 that overlaps with the first photonic crystal 52. The distances D1 and D2 may be the same. This makes it possible to easily manufacture the first hole 53 and the second hole 55.

[0030] 2, the third semiconductor layer 60 is provided on the photonic crystal layer 50. The third semiconductor layer 60 is provided between the photonic crystal layer 50 and the contact layer 70. The material of the third semiconductor layer 60 is, for example, the same as that of the second semiconductor layer 40. The third semiconductor layer 60 can increase the distance between the light emitting layer 30 and the contact layer 70. This can reduce absorption of light generated in the light emitting layer 30 by the contact layer 70.

[0031] The contact layer 70 is provided on the third semiconductor layer 60. The contact layer 70 is provided between the third semiconductor layer 60 and the second electrode 82. The contact layer 70 overlaps with the first region 50a and the second region 50b when viewed from the stacking direction. The contact layer 70 overlaps with the first photonic crystal 52 and the second photonic crystal 54 when viewed from the stacking direction.

[0032] The contact layer 70 is, for example, a p-type GaAs layer doped with C. The impurity concentration of the contact layer 70 is higher than the impurity concentrations of the second semiconductor layer 40, the photonic crystal layer 50, and the third semiconductor layer 60. The resistivity of the contact layer 70 is lower than the resistivities of the second semiconductor layer 40, the photonic crystal layer 50, and the third semiconductor layer 60.

[0033] The first electrode 80 is provided under the substrate 10. The substrate 10 is provided between the first electrode 80 and the first semiconductor layer 20. The substrate 10 may be in ohmic contact with the first electrode 80. The first electrode 80 is electrically connected to the first semiconductor layer 20 via the substrate 10. As the first electrode 80, for example, a layer formed by laminating a Ti layer, an Au layer, a Pt layer, and an Au layer in this order from the substrate 10 side is used. The first electrode 80 is one of the electrodes for injecting a current into the light emitting layer 30.

[0034] The second electrode 82 is provided on the contact layer 70. The contact layer 70 may be in ohmic contact with the second electrode 82. The second electrode 82 is electrically connected to the second semiconductor layer 40 via the contact layer 70, the third semiconductor layer 60, and the photonic crystal layer 50. As the second electrode 82, for example, a layer formed by laminating a Ti layer, an Al layer, and an Au layer in this order from the contact layer 70 side is used. The second electrode 82 is the other electrode for injecting a current into the light emitting layer 30.

[0035] An opening 84 is formed in the second electrode 82. When viewed from the stacking direction, the opening 84 overlaps with the second photonic crystal 54. When viewed from the stacking direction, the second electrode 82 overlaps with the first photonic crystal 52.

[0036] 1.2. Operation In the light emitting device 100, a pin diode is formed by the p-type second semiconductor layer 40, the i-type light emitting layer 30, and the n-type first semiconductor layer 20. In the light emitting device 100, when a forward bias voltage of the pin diode is applied between the first electrode 80 and the second electrode 82, a current is injected into the light emitting layer 30, causing recombination of electrons and holes in the light emitting layer 30. This recombination produces light emission. The light generated in the light emitting layer 30 propagates through the light emitting layer 30 while receiving gain, and resonates in the in-plane direction due to the distributed feedback effect of the first photonic crystal 52 and the second photonic crystal 54 (diffraction in the in-plane direction in each photonic crystal), resulting in laser oscillation.

[0037] The laser oscillated light is emitted in a direction different from the in-plane direction due to the photonic crystal effect of the second photonic crystal 54. The second photonic crystal 54 emits the laser oscillated light in the stacking direction, for example, by using first-order diffraction. Light heading toward the first semiconductor layer 20 side is reflected by the first semiconductor layer 20 and emitted from the contact layer 70 side. The light emitting device 100 emits light from the opening 84.

[0038] 1, when viewed from the stacking direction, first holes 53 of first photonic crystal 52 are arranged in a square lattice pattern in the X-axis and Y-axis directions, and second holes 55 of second photonic crystal 54 have inclined surfaces 56 inclined at 45° with respect to the X-axis and Y-axis. Therefore, in second photonic crystal 54, resonance in the X-axis direction and resonance in the Y-axis direction can be connected, and two-dimensional resonance of light can be strengthened.

[0039] Although not shown, the light emitting device 100 may be mounted in a junction-down manner on a mounting substrate (not shown). In this case, the first semiconductor layer 20 may not constitute a DBR, and the second semiconductor layer 40 or the third semiconductor layer 60 may constitute a DBR.

[0040] Although the above describes an InGaAs-based light emitting layer 30, various material systems capable of emitting light when a current is injected depending on the wavelength of the emitted light can be used for the light emitting layer 30. For example, semiconductor materials such as InGaN-based, AlGaN-based, AlGaAs-based, InGaAsP-based, InP-based, GaP-based, and AlGaInP-based materials can be used.

[0041] 1.3. Effects For example, when a distributed feedback controlled photonic crystal and a surface emission controlled photonic crystal are superimposed and holes forming the surface emission controlled photonic crystal are arranged between adjacent holes forming the distributed feedback controlled photonic crystal, the original periodicity is not maintained in the distributed feedback controlled photonic crystal. In this case, two types of photonic crystal structures are mixed in the same region in a plan view, so that in at least one of the photonic crystals, the original periodic structure is not maintained due to the influence of the other photonic crystal, and scattering loss occurs.

[0042] The light emitting device 100 includes a first semiconductor layer 20 having a first conductivity type, a second semiconductor layer 40 having a second conductivity type different from the first conductivity type, a light emitting layer 30 provided between the first semiconductor layer 20 and the second semiconductor layer 40, and a photonic crystal layer 50 provided on the second semiconductor layer 40 opposite the light emitting layer 30. The photonic crystal layer 50 includes a first region 50a provided with a first photonic crystal 52 that resonates light emitted from the light emitting layer 30 in an in-plane direction and does not emit the light in a direction different from the in-plane direction, and a second region 50b provided with a second photonic crystal 54 that does not overlap with the first region 50a when viewed from the stacking direction and that emits light emitted from the light emitting layer 30 in a direction different from the in-plane direction.

[0043] Therefore, in the light emitting device 100, it is possible to reduce scattering by the second photonic crystal 54 of light resonating in the first photonic crystal 52, i.e., scattering loss caused by the original periodicity not being maintained in the first photonic crystal 52. This makes it possible to suppress an increase in the threshold value and a decrease in the slope efficiency.

[0044] Furthermore, since the light emitting device 100 uses the two photonic crystals 52 and 54, the light generated in the light emitting layer 30 is multi-wavelength, which makes it possible to reduce the influence of speckles.

[0045] Furthermore, in the light emitting device 100, the first photonic crystal 52, which resonates the light generated in the light emitting layer 30 in an in-plane direction, and the second photonic crystal 54, which emits the light generated in the light emitting layer 30 in a direction different from the in-plane direction, can be individually controlled and optimized.

[0046] Furthermore, in the light emitting device 100, light is not emitted from the region that overlaps with the first photonic crystal 52 when viewed from the stacking direction, so light can be resonated efficiently with low loss. This allows laser oscillation in a smaller area. Therefore, for example, when multiple light emitting devices 100 are arranged in an array, the intervals between the arrays become smaller, and the light intensity can be adjusted for each small area.

[0047] In the light emitting device 100, the second photonic crystal 54 emits light generated in the light emitting layer 30 in the stacking direction. Therefore, in the light emitting device 100, the light generated in the light emitting layer 30 can be emitted using first-order diffraction.

[0048] Light emitting device 100 has second electrode 82 and contact layer 70 provided between photonic crystal layer 50 and second electrode 82, and contact layer 70 overlaps first region 50a and second region 50b when viewed from the stacking direction. Therefore, in light emitting device 100, the intensity of light resonating in the in-plane direction by first photonic crystal 52 can be strengthened compared to, for example, a case in which the contact layer does not overlap the first region.

[0049] In the light emitting device 100, the first region 50a surrounds the second region 50b when viewed from the stacking direction. Therefore, in the light emitting device 100, light that resonates in the in-plane direction by the first photonic crystal 52 can be efficiently guided to the second photonic crystal 54.

[0050] In the light emitting device 100, the shape of the first hole 53 has rotational symmetry when viewed from the stacking direction, but the shape of the second hole 55 does not have rotational symmetry. Therefore, in the light emitting device 100, it is possible to suppress a non-illuminated spot directly above the light emitting device 100 that occurs due to light canceling out due to too good symmetry.

[0051] 2. Manufacturing method of light-emitting device Next, a method for manufacturing the light emitting device 100 according to this embodiment will be described with reference to the drawings. Fig. 3 is a cross-sectional view that typically shows the manufacturing process of the light emitting device 100 according to this embodiment.

[0052] 3, a first semiconductor layer 20, a light emitting layer 30, and a second semiconductor layer 40 are epitaxially grown in this order on a substrate 10. Examples of the epitaxial growth method include a metal organic chemical vapor deposition (MOCVD) method and a molecular beam epitaxy (MBE) method.

[0053] Next, the photonic crystal layer 50 is epitaxially grown on the second semiconductor layer 40. During the epitaxial growth of the photonic crystal layer 50, patterning is performed to form the first holes 53 and the second holes 55. This makes it possible to form the photonic crystal layer 50 having the first photonic crystal 52 and the second photonic crystal 54. Examples of the method for epitaxial growth include the MOCVD method and the MBE method. The patterning is performed by, for example, photolithography and etching, or electron beam lithography and etching.

[0054] 2, a third semiconductor layer 60 and a contact layer 70 are epitaxially grown in this order on the photonic crystal layer 50. Examples of the method for epitaxial growth include the MOCVD method and the MBE method.

[0055] Next, a first electrode 80 is formed under the substrate 10. Next, a second electrode 82 is formed on the contact layer 70. The first electrode 80 and the second electrode 82 are formed by, for example, a vacuum deposition method or a sputtering method. The order in which the first electrode 80 and the second electrode 82 are formed is not particularly limited.

[0056] Through the above steps, the light emitting device 100 can be manufactured.

[0057] 3. Modifications of the Light Emitting Device 3.1. First variant Next, a light emitting device according to a first modification of this embodiment will be described with reference to the drawings. Fig. 4 is a cross-sectional view that shows a schematic view of a light emitting device 200 according to a first modification of this embodiment.

[0058] Hereinafter, in the light emitting device 200 according to the first modified example of this embodiment, the components having the same functions as the components of the light emitting device 100 according to this embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted. This also applies to the light emitting devices according to the second and third modified examples of this embodiment described later.

[0059] In the light emitting device 100 described above, the first photonic crystal 52 distributes and feeds back the light generated in the light emitting layer 30 .

[0060] In contrast, in the light emitting device 200, the first photonic crystal 52 causes distributed reflection of the light generated in the light emitting layer 30.

[0061] 4, in the light emitting device 200, the first hole 53 penetrates from the upper surface of the contact layer 70 to the first semiconductor layer 20. In the illustrated example, the bottom surface of the first hole 53 is located between the upper surface and the lower surface of the first semiconductor layer 20 in the stacking direction.

[0062] In the light emitting device 200, protons (H +) is implanted. The implantation region 210 is provided on the side of the light emitting layer 30, the second semiconductor layer 40, the second region 50b of the photonic crystal layer 50, the third semiconductor layer 60, and the contact layer 70. The implantation region 210 surrounds the light emitting layer 30, the second semiconductor layer 40, the second region 50b, the third semiconductor layer 60, and the contact layer 70, for example, when viewed from the stacking direction. The first region 50a of the photonic crystal layer 50 is composed of the implantation region 210. The implantation region 210 has insulating properties.

[0063] The first holes 53 of the first photonic crystal 52 are formed in the injection region 210. The multiple first holes 53 form a photonic band gap due to a large refractive index difference between the semiconductor layer and the through holes.

[0064] The contact layer 70 overlaps with the second region 50b when viewed from the stacking direction. The contact layer 70 does not overlap with the first region 50a when viewed from the stacking direction. The second electrode 82 overlaps with the second region 50b when viewed from the stacking direction. The second electrode 82 does not overlap with the first region 50a when viewed from the stacking direction.

[0065] The light generated in the light emitting layer 30 is distributed and reflected in the in-plane direction by the first photonic crystal 52, and undergoes Fabry-Perot resonation in the region surrounded by the first photonic crystal 52 as viewed from the stacking direction. The second photonic crystal 54 emits the Fabry-Perot resonated light, for example, in the stacking direction. Note that light propagating in a direction away from the second photonic crystal 54 as viewed from the stacking direction is gradually attenuated by the photonic band gap in the region overlapping with the first photonic crystal 52.

[0066] In the light emitting device 200, the contact layer 70 does not overlap the first region 50a, but overlaps the second region 50b, as viewed from the stacking direction. Therefore, in the light emitting device 200, current is unlikely to be injected into the first photonic crystal 52, and since it is not a light emitting region, even if dislocations or the like occur, the effect on light is small, and reliability can be improved. Note that, since no current is injected into the first region 50a, absorption may occur in the light emitting layer 30 in the region overlapping with the first region 50a in plan view. To suppress this, a process such as Zn diffusion may be performed on the light emitting layer 30 in the first region 50a. Zn diffusion can destroy the quantum well structure of the light emitting layer 30 in this region, thereby reducing absorption loss.

[0067] 3.2. Second variant Next, a light emitting device according to a second modification of this embodiment will be described with reference to the drawings. 5 is a plan view diagrammatically illustrating a light emitting device 300 according to a second modified example of this embodiment.

[0068] As shown in Figure 5, light emitting device 300 differs from light emitting device 100 described above in that it has a reflector 310. For convenience, components other than photonic crystal layer 50 and reflector 310 are not shown in Figure 5.

[0069] Reflector 310 surrounds first region 50a of photonic crystal layer 50 when viewed from the stacking direction. Reflector 310 surrounds first photonic crystal 52 when viewed from the stacking direction. Reflector 310 is provided on the side of light-emitting layer 30. The material of reflector 310 is, for example, a metal or a dielectric. Reflector 310 is formed by, for example, a vacuum deposition method, a sputtering method, a CVD (Chemical Vapor Deposition) method, or the like.

[0070] The reflecting portion 310 reflects light generated in the light emitting layer 30. Specifically, the reflecting portion 310 reflects light that is generated in the light emitting layer 30 and propagates in a direction away from the second photonic crystal 54 when viewed from the stacking direction.

[0071] The light emitting device 300 includes a reflecting portion 310 that surrounds the first region 50a when viewed from the stacking direction and reflects light emitted from the light emitting layer 30. Therefore, in the light emitting device 300, when viewed from the stacking direction, light leaking from the first region 50a can be returned to the first region 50a.

[0072] 3.3. Third variant Next, a light emitting device according to a third modified example of this embodiment will be described with reference to the drawings. Fig. 6 is a plan view showing a light emitting device 400 according to a third modified example of this embodiment. For convenience, Fig. 6 omits illustration of components other than the first hole 53 of the first photonic crystal 52 and the second hole 55 of the second photonic crystal 54.

[0073] 1, in the light emitting device 100 described above, the first holes 53 of the first photonic crystal 52 are arranged in a square lattice pattern when viewed from the stacking direction, and the second holes 55 of the second photonic crystal 54 are arranged in a square lattice pattern.

[0074] In contrast, in the light emitting device 400, the first holes 53 are arranged in a regular triangular lattice pattern when viewed from the stacking direction as shown in Fig. 6. The second holes 55 are arranged in a regular triangular lattice pattern.

[0075] In the illustrated example, adjacent first holes 53 are aligned in the X-axis direction. Adjacent second holes 55 are aligned in the X-axis direction. When viewed from the stacking direction, the shape of the second holes 55 is a rhombus. The second holes 55 have a first inclined surface 57 and a second inclined surface 58.

[0076] The first inclined surface 57 is inclined at 30° with respect to the X-axis (with respect to the +X-axis direction). The first inclined surface 57 reflects, for example, light propagating in the +X-axis direction in a direction inclined at 60° with respect to the X-axis, as indicated by arrow A.

[0077] The second inclined surface 58 is inclined at 60° with respect to the X-axis. The second inclined surface 58 reflects, for example, light propagating in the +X-axis direction in a direction inclined at 120° with respect to the X-axis, as indicated by arrow B.

[0078] In the light emitting device 400, it is possible to connect a resonance in the X-axis direction, a resonance in a direction tilted at 60° with respect to the X-axis, and a resonance in a direction tilted at 120° with respect to the X-axis in the second photonic crystal 54. In this way, in the light emitting device 400, it is possible to connect resonances in three different directions, thereby strengthening the two-dimensional resonance of light.

[0079] As long as resonances in three different directions can be connected, the inclination angles of the inclined surfaces 57 and 58 with respect to the X-axis are not particularly limited. As shown in FIG. 7, the first inclined surface 57 may be inclined at 90° with respect to the X-axis, and the second inclined surface 58 may be inclined at 60° with respect to the X-axis, as viewed from the stacking direction. Although not shown, the first inclined surface 57 may be inclined at 90° with respect to the X-axis, and the second inclined surface 58 may be inclined at 120° with respect to the X-axis, as viewed from the stacking direction. The first inclined surface 57 may be inclined at 150° with respect to the X-axis, and the second inclined surface 58 may be inclined at 180° with respect to the X-axis (i.e., parallel). The first inclined surface 57 may be inclined at 30° with respect to the X-axis, and the second inclined surface 58 may be inclined at 0° with respect to the X-axis (i.e., parallel).

[0080] 4. Projector Next, a projector according to this embodiment will be described with reference to the drawings. Fig. 8 is a diagram showing a schematic diagram of a projector 500 according to this embodiment.

[0081] 8, the projector 500 includes, for example, a light source 510, a light modulation device 520, a cross dichroic prism 530, a projection device 540, and a housing 550. The projector 500 is, for example, a backlight type projector.

[0082] Three light sources 510 are provided. A first light source 510R of the three light sources 510 emits red light. A second light source 510G of the three light sources 510 emits green light. A third light source 510B of the three light sources 510 emits blue light.

[0083] The light source 510 includes, for example, a PCSEL array 512, a submount 514, a base 516, a Peltier module 517, a heat sink 518, and a cooling section 519.

[0084] The PCSEL array 512 has, for example, a plurality of light emitting devices 100. The plurality of light emitting devices 100 are arranged in an array. The number of the plurality of light emitting devices 100 is not particularly limited. The substrate 10 of the plurality of light emitting devices 100 may be common.

[0085] The PCSEL array 512 of the first light source 510R has a first light emitting device 100R that emits red light as the light emitting device 100. The PCSEL array 512 of the second light source 510G has a second light emitting device 100G that emits green light as the light emitting device 100. The PCSEL array 512 of the third light source 510B has a third light emitting device 100B that emits blue light as the light emitting device 100.

[0086] The submount 514 supports the PCSEL array 512. The material of the submount 514 is, for example, SiC. The base 516 supports the submount 514. The material of the submount 514 is, for example, copper. The Peltier module 517 supports the submount 514. The heat sink 518 supports the Peltier module 517. The cooling unit 519 cools the heat sink 518. The cooling unit 519 is, for example, a blower.

[0087] In the light source 510 , heat generated in the light emitting device 100 can be dissipated from the heat sink 518 via the submount 514 , the base 516 , and the Peltier module 517 .

[0088] The light emitted from the light source 510 is incident on the light modulation device 520. Three light modulation devices 520 are provided, corresponding to the number of light sources 510. The light modulation device 520 converts the incident light into The light is modulated in accordance with image information. The light modulation device 520 is, for example, a transmissive liquid crystal light valve.

[0089] The three color lights modulated by the light modulation device 520 are incident on the cross dichroic prism 530. The cross dichroic prism 530 is formed by bonding together four right-angle prisms. A dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are provided on the inner surface of the cross dichroic prism 530. The three color lights are synthesized by these dielectric multilayer films to form light that represents a color image.

[0090] The light combined by the cross dichroic prism 530 is incident on the projection device 540. The projection device 540 projects the combined light, for example, on a screen (not shown). The projection device 540 is, for example, a projection lens.

[0091] The housing 550 houses the light source 510, the light modulation device 520, the cross dichroic prism 530, and a part of the projection device 540. The shape of the housing 550 is not particularly limited.

[0092] 5. Projector Modifications Next, a projector according to a modification of this embodiment will be described with reference to the drawings. Fig. 9 is a diagram illustrating a projector 600 according to a modification of this embodiment.

[0093] Hereinafter, in a projector 600 according to a modified example of this embodiment, components having the same functions as those of the components of the projector 500 according to this embodiment described above are given the same reference numerals, and detailed description thereof will be omitted.

[0094] In the above-described projector 500, as shown in FIG. 8, three light sources 510 are provided, a first light source 510R emits red light, a second light source 510G emits green light, and a third light source 510B emits blue light.

[0095] In contrast, in projector 600, one light source 510 emits red light, green light, and blue light as shown in Fig. 9. Therefore, projector 600 can be made smaller than projector 500, for example.

[0096] A plurality of light sources 510 are provided. In the illustrated example, the heat sink 518 of the plurality of light sources 510 is common. The cooling unit 519 of the plurality of light sources 510 is common. The PCSEL array 512 has, for example, a first light emitting device 100R that emits red light, a second light emitting device 100G that emits green light, and a third light emitting device 100B that emits blue light. The first light emitting device 100R, the second light emitting device 100G, and the third light emitting device 100B are arranged, for example, in this order in a matrix shape. The number of the plurality of light emitting devices 100 is not particularly limited. For example, in the second photonic crystal region, one light emitting device 100 resonates in an in-plane direction by third-order diffraction, and emits light in a total of four directions inclined with respect to the stacking direction by first-order and second-order diffraction (each having an X-axis direction and a Y-axis direction).

[0097] There is provided only one light modulation device 520. Light emitted from the light source 510 is incident on the light modulation device 520. The light emitted from the light modulation device 520 is incident on the projection device 540 without passing through a cross dichroic prism.

[0098] Although not shown, an optical element such as a microlens array or a prism may be provided in the optical path between the light source 510 and the light modulation device 520.

[0099] In the above example, a transmissive liquid crystal light valve is used as the light modulation device, but a reflective light valve may be used, or a light valve other than liquid crystal, such as a digital micro mirror device, may be used. The configuration of the projection device may be changed as appropriate depending on the type of light valve used.

[0100] Alternatively, an image may be formed directly without using the light modulation device 520 by controlling the light emitting devices 100 of the light source 510 as pixels of an image in accordance with image information.

[0101] In addition, the light source 510 can also be applied to a light source device of a scanning type image display device having a scanning means, which is an image forming device that displays an image of a desired size on a display surface by scanning light from the light source 510 on a screen.

[0102] The light emitting device according to the above-described embodiment can also be used in a projector. The light emitting device according to the above-described embodiment can be used as a light source for, for example, a three-dimensional modeling device, a head mounted display, a light source for promoting plant structural properties, indoor and outdoor lighting, a laser printer, a scanner, an in-vehicle light, a sensing device such as a pulse measuring device that uses light, a communication device, and the like.

[0103] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be appropriately combined.

[0104] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments, or configurations that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0105] The following can be derived from the above-described embodiment and modifications.

[0106] One aspect of the light emitting device is a first semiconductor layer having a first conductivity type; a second semiconductor layer having a second conductivity type different from the first conductivity type; a light emitting layer provided between the first semiconductor layer and the second semiconductor layer; a photonic crystal layer provided on the second semiconductor layer opposite to the light emitting layer; having The photonic crystal layer comprises: a first region provided with a first photonic crystal that resonates the light emitted from the light emitting layer in a direction perpendicular to a stacking direction of the first semiconductor layer and the light emitting layer and does not emit the light in a direction different from the perpendicular direction; a second region in which a second photonic crystal is provided, the second region not overlapping with the first region as viewed from the stacking direction and configured to emit light emitted from the light emitting layer in a direction different from the orthogonal direction; has.

[0107] According to this light emitting device, it is possible to reduce scattering of light that resonates in the first photonic crystal, due to the second photonic crystal.

[0108] In one embodiment of the light emitting device, The second photonic crystal may emit light generated in the light emitting layer in the stacking direction.

[0109] According to this light emitting device, the light generated in the light emitting layer can be emitted using first-order diffraction.

[0110] In one embodiment of the light emitting device, An electrode; a contact layer provided between the photonic crystal layer and the electrode; having When viewed from the stacking direction, the contact layer may overlap the first region and the second region.

[0111] According to this light emitting device, the intensity of the light resonating in the in-plane direction by the first photonic crystal can be increased.

[0112] In one embodiment of the light emitting device, An electrode; a contact layer provided between the photonic crystal layer and the electrode; having When viewed from the stacking direction, the contact layer may not overlap the first region but may overlap the second region.

[0113] According to this light emitting device, current is less likely to be injected into the first photonic crystal, and reliability can be improved.

[0114] In one embodiment of the light emitting device, When viewed from the stacking direction, the first region may surround the second region.

[0115] According to this light emitting device, light that resonates in the in-plane direction by the first photonic crystal can be efficiently guided to the second photonic crystal.

[0116] In one embodiment of the light emitting device, The light-emitting layer may further include a reflecting portion that surrounds the first region when viewed in the stacking direction and reflects light emitted from the light-emitting layer.

[0117] According to this light emitting device, when viewed in the stacking direction, light leaking from the first region can be returned to the first region.

[0118] In one embodiment of the light emitting device, the first photonic crystal has a plurality of first holes that are periodically arranged; the second photonic crystal has a plurality of second holes that are periodically arranged; When viewed from the stacking direction, the shape of each of the plurality of first holes may be different from the shape of each of the plurality of second holes.

[0119] In one embodiment of the light emitting device, When viewed from the stacking direction, the shape of each of the plurality of first holes has rotational symmetry; The shape of each of the plurality of second holes does not have to have rotational symmetry.

[0120] According to this light emitting device, it is possible to suppress a non-illuminated spot that occurs directly above the light emitting device due to light canceling out due to too good symmetry.

[0121] One aspect of the projector is The present invention has one aspect of the light emitting device. [Explanation of symbols]

[0122] 10...substrate, 20...first semiconductor layer, 30...light emitting layer, 40...second semiconductor layer, 50...photonic crystal layer, 50a...first region, 50b...second region, 52...first photonic crystal, 53...first hole, 54...second photonic crystal, 55...second hole, 56...inclined surface, 57...first inclined surface, 58...second inclined surface, 60...third semiconductor layer, 70...contact layer, 80...first electrode, 82...second electrode, 84...opening, 100...light emitting device, 100R...first light emitting device, 100G...second light emitting device, 100B...third light emitting Apparatus, 200...light emitting device, 210...injection region, 300...light emitting device, 310...reflecting portion, 400...light emitting device, 500...projector, 510...light source, 510R...first light source, 510G...second light source, 510B...third light source, 512...PCSEL array, 514...submount, 516...base, 517...peltier module, 518...heat sink, 519...cooling portion, 520...light modulation device, 530...cross dichroic prism, 540...projection device, 550...housing, 600...projector

Claims

1. a first semiconductor layer having a first conductivity type; a second semiconductor layer having a second conductivity type different from the first conductivity type; a light emitting layer provided between the first semiconductor layer and the second semiconductor layer; a photonic crystal layer provided on the second semiconductor layer opposite to the light emitting layer; having The photonic crystal layer comprises: a first region provided with a first photonic crystal that resonates light emitted from the light emitting layer in a direction perpendicular to a stacking direction of the first semiconductor layer and the light emitting layer and does not emit the light in a direction different from the perpendicular direction; a second region in which a second photonic crystal is provided, the second region not overlapping with the first region as viewed from the stacking direction and configured to emit light emitted from the light emitting layer in a direction different from the orthogonal direction; A light emitting device comprising:

2. In claim 1, The second photonic crystal emits light generated in the light emitting layer in the stacking direction.

3. In claim 1, An electrode; a contact layer provided between the photonic crystal layer and the electrode; having the contact layer overlaps with the first region and the second region when viewed from the stacking direction.

4. In claim 1, An electrode; a contact layer provided between the photonic crystal layer and the electrode; having When viewed from the stacking direction, the contact layer does not overlap the first region and overlaps the second region.

5. In claim 1, The light emitting device, wherein the first region surrounds the second region as viewed from the stacking direction.

6. In claim 5, the light emitting device further comprising a reflecting portion that surrounds the first region when viewed from the stacking direction and reflects light emitted from the light emitting layer.

7. In claim 1, the first photonic crystal has a plurality of first holes that are periodically arranged; the second photonic crystal has a plurality of second holes that are periodically arranged; A light emitting device, wherein a shape of each of the plurality of first holes and a shape of each of the plurality of second holes are different when viewed from the stacking direction.

8. In claim 7, When viewed from the stacking direction, a shape of each of the plurality of first holes has rotational symmetry; A light emitting device, wherein the shape of each of the plurality of second holes does not have rotational symmetry.

9. A projector comprising the light emitting device according to claim 1 .

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