Vertical-cavity surface-emitting semiconductor laser diode and method for the manufacture thereof
The present invention includes a vertical-cavity surface-emitting semiconductor laser diode having a resonator with a first distributed Bragg reflector, an active zone which has a p-n junction and is embedded into a semiconductor layer sequence, and a second distributed Bragg reflector. The semiconductor laser diode has an emission wavelength λ, wherein a periodic structure is arranged within the resonator as an optical grating made of semiconductive material and dielectric material, the main plane of extension of which is arranged substantially perpendicularly to the direction of emission of the semiconductor laser diode. The periodic structure is in direct contact with at least one of the semiconductor layers embedding the active zone and with at least one of the two distributed Bragg reflectors.
1. A vertical-cavity surface-emitting semiconductor laser diode having a resonator with a first distributed Bragg reflector, an active zone which has a p-n junction and is embedded into a sequence of semiconductor layers, and a second distributed Bragg reflector, the semiconductor laser diode having an emission wavelength λ, characterized by
a periodic structure arranged within the resonator as an optical grating made of a semiconductive material and a dielectric material;
a main plane of extension of the periodic structure being arranged substantially perpendicularly to a direction of emission of the semiconductor laser diode; and
the periodic structure being in direct contact with at least one of the semiconductor layers and with at least one of the distributed Bragg reflectors, and wherein
the periodic structure is made of at least one material of the semiconductor layers and at least one material of the two distributed Bragg reflectors,
the period of the periodic structure is at most λ/n, n being a function of the index of refraction of the semiconductive material and/or the index of refraction of the dielectric material, and
n is the higher of the two indices of refraction.
2. The semiconductor laser diode according to claim 1 , wherein the period of the periodic structure is at most λ/2n.
3. The semiconductor laser diode according to claim 2 , wherein the periodic structure is embodied as a subwavelength grating.
4. The semiconductor laser diode according to claim 1 , wherein the periodic structure directly adjoins the second distributed Bragg reflector.
5. The semiconductor laser diode according to claim 4 , wherein a material of the periodic structure is the same as a material of an adjoining layer of the second distributed Bragg reflector.
6. The semiconductor laser diode according to claim 5 , wherein the second distributed Bragg reflector is an alternating layer system consisting of at least two materials having different indices of refraction.
7. The semiconductor laser diode according to claim 5 , wherein a dielectric material of the periodic structure is the same as a material of an adjoining layer of the second distributed Bragg reflector.
8. The semiconductor laser diode according to claim 1 , wherein the resonator further comprises a tunnel contact layer on a p side of the active zone.
9. The semiconductor laser diode according to claim 8 , wherein a dimension of a projection of the periodic structure onto the tunnel contact layer corresponds at least to a dimension of an aperture of the tunnel contact layer.
10. The semiconductor laser diode according to claim 9 , wherein the tunnel contact layer adjoins an n-doped semiconductor layer.
11. The semiconductor laser diode according to claim 8 , wherein an area of a projection of the periodic structure onto the tunnel contact layer corresponds at least to an area of an aperture of the tunnel contact layer.
12. A vertical-cavity surface-emitting semiconductor laser diode having a resonator with a first distributed Bragg reflector, an active zone which has a p-n junction and is embedded into a sequence of semiconductor layers, and a second distributed Bragg reflector, the semiconductor laser diode having an emission wavelength λ, characterized by
a periodic structure arranged within the resonator as an optical grating made of a semiconductive material and a dielectric material;
a main plane of extension of the periodic structure being arranged substantially perpendicularly to a direction of emission of the semiconductor laser diode; and
the periodic structure being in direct contact with at least one of the semiconductor layers and with at least one of the distributed Bragg reflectors, and wherein
the resonator further comprises a tunnel contact layer on a p side of the active zone,
a dimension of a projection of the periodic structure onto the tunnel contact layer corresponds at least to a dimension of an aperture of the tunnel contact layer,
the tunnel contact layer adjoins an n-doped semiconductor layer, and
the periodic structure directly adjoins the n-doped semiconductor layer.
13. The semiconductor laser diode according to claim 12 , wherein the semiconductive material of the periodic structure is the same as a material of the n-doped semiconductor layer.
14. The semiconductor laser diode according to claim 12 , wherein the periodic structure is made of at least one material of the semiconductor layers and at least one material of one of the two distributed Bragg reflectors.
15. The semiconductor laser diode according to claim 14 , wherein a period of the periodic structure is less than or equal to λ.
16. The semiconductor laser diode according to claim 14 , wherein a period of the periodic structure is less than or equal to λ/2.
17. The semiconductor laser diode according to claim 14 , wherein the period of the periodic structure is at most λ/n, n being a function of the index of refraction of the semiconductive material and/or the index of refraction of the dielectric material.
18. The semiconductor laser diode according to claim 17 , wherein n is the higher of the two indices of refraction.
19. The semiconductor laser diode according to claim 17 , wherein the period of the periodic structure is at most λ/2n.
20. The semiconductor laser diode according to claim 19 , wherein the periodic structure is embodied as a subwavelength grating.
21. The semiconductor laser diode according to claim 12 , wherein the periodic structure directly adjoins the second distributed Bragg reflector.
22. The semiconductor laser diode according to claim 21 , wherein a material of the periodic structure is the same as a material of an adjoining layer of the second distributed Bragg reflector.
23. The semiconductor laser diode according to claim 22 , wherein the second distributed Bragg reflector is an alternating layer system consisting of at least two materials having different indices of refraction.
24. The semiconductor laser diode according to claim 22 , wherein the dielectric material of the periodic structure is the same as a material of an adjoining layer of the second distributed Bragg reflector.
25. The semiconductor laser diode according to claim 12 , wherein the semiconductive material of the periodic structure is the same as a material of the n-doped semiconductor layer.