Extended wavelength strained layer lasers having nitrogen disposed therein

• US 5,719,894 A
• Filed: 09/25/1996
• Issued: 02/17/1998
• Est. Priority Date: 09/25/1996
• Status: Expired due to Term

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Picolight Inc (Lumentum Holdings Inc.)
• Inventors: Jewell, Jack L., Temkin, Henryk
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Kang, Ellen Eunjoo
• Application Number:
  US08/721,590
• Time in Patent Office: 510 Days
• Field of Search: 372/45, 372/46, 372/43, 372/96, 372/92, 257/9, 257/12
• US Class Current: 372/45.011
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/105 with a resonant cavity structure
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2302/00 Amplification / lasing wavelength
• CPC Class Codes: H01S 5/1221 Detuning between Bragg wavelength and gain maximum
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/2215 using native oxidation of semiconductor layers
• CPC Class Codes: H01S 5/3201 incorporating bulkstrain effects, e.g. strain compensation, strain related to polarisation
• CPC Class Codes: H01S 5/3202 grown on specifically orientated substrates, or using orientation dependent growth
• CPC Class Codes: H01S 5/3206 ordering or disordering the natural superlattice in ternary or quaternary materials
• CPC Class Codes: H01S 5/32366 (In)GaAs with small amount of N
• CPC Class Codes: H01S 5/32383 small amount of Thallum (TI), e.g. GaTIP
• CPC Class Codes: H01S 5/3403 having a strained layer structure in which the strain performs a special function, e.g. general strain effects, strain versus polarisation
• CPC Class Codes: H01S 5/3406 including strain compensation
• CPC Class Codes: H01S 5/342 containing short period superlattices [SPS]
• CPC Class Codes: H01S 5/34306 emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers
• CPC Class Codes: H01S 5/34313 with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs

Abstract

Several methods are used in novel ways with newly identified and viable parameters to decrease the peak transition energies of the pseudomorphic InGaAs/GaAs heterostructures. These techniques, taken separately or in combination, suffice to permit operation of light emitting devices at wavelengths of 1.3 μm or greater of light-emitting electro-optic devices. These methods or techniques, by example, include: (1) utilizing new superlattice structures having high In concentrations in the active region, (2) utilizing strain compensation to increase the usable layer thickness for quantum wells with appropriately high In concentrations, (3) utilizing appropriately small amounts of nitrogen (N) in the pseudomorphic InGaAsN/GaAs laser structure, and (4) sue of nominal (111) oriented substrates to increase the usable layer thickness for quantum wells with appropriately high In concentrations. In all of the above techniques, gain offset may be utilized in VCSELs to detune the emission energy lower than the peak transition energy, by about 25 meV or even more, via appropriate DBR spacing. Gain offset may also be utilized in some forms of in-plane lasers. Increased temperature may also be used to decrease peak transition energy (and therefore the emission energy) by about 50 meV/100° C. All these techniques are furthermore applicable to other material systems, for example, extending the emission wavelength for laser diodes grown on InP substrates. Additionally, structures which utilize the above techniques are discussed.

Claims

1. A light emitting device having at least a substrate and an active region, said light emitting device comprising:

said substrate having a substrate lattice constant between 5.63 Å and

5.67 Å

;

said active region comprising at least one pseudomorphic light emitting active layer disposed above said substrate, said active layer comprising at least In, Ga, As and N, said active layer having a thickness equal to or less than a respective CT, where;

space="preserve" listing-type="equation">CT=(0.4374/f) ln (CT/4)+1!,

where f is an average lattice mismatch of said active layer normalized to a lattice constant of 5.65 Å

;

said active layer having an average sum of In and Sb concentrations in said active layer at 16.5% or greater of a semiconductor material in said active layer and said nitrogen content less than 1% of a group V semiconductor material in said active region; and

wherein said light emitting device has an emission wavelength of at least 1.3 μ

m.

2. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0095, and w+y≧

0.33.

3. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.009, and w+y≧

0.33.

4. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0068, and w+y≧

0.4.

5. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0035, and w+y≧

0.5.

6. The device recited in claim 1, wherein said active region has a peak transition wavelength of at least 1.24 μ

m.

7. The device recited in claim 1, wherein said substrate comprises GaAs.

8. The device recited in claim 1, wherein said substrate consists essentially of GaAs.

9. The device recited in claim 1, wherein said substrate has an orientation between 0°

and 4°

off the (001) orientation.

10. The device recited in claim 1, wherein said superlattice having an average sum of In and Sb concentrations of greater than 50% of the type three semiconductor material.

11. The device recited in claim 1, wherein said emission wavelength of at least 1.3 μ

m occurs with said active layer at a temperature of 300 K or less.

12. The device recited in claim 1, wherein said emission wavelength is 1.3 μ

m with said active layer at a temperature greater than 300 K.

13. The device recited in claim 1, further comprising:

a first conductive layer having a first conductivity type, said first conductive layer disposed in electrical communication with said active layer;

a second conductive layer having a second conductivity type, said second conductive layer being disposed above said active layer and in electrical communication therewith; and

electrical communication means for providing electrical current to said active layer.

14. The device recited in claim 13, further comprising a bottom mirror disposed below said active layer and a top mirror disposed above said active layer, said top and bottom mirrors defining an optical cavity having a cavity resonance at a resonance wavelength corresponding to a resonance energy;

said resonance wavelength in μ

m, as measured in vacuum, being equal to 1.24 divided by said resonance energy, in electron volts.

15. The device recited in claim 14, wherein said bottom mirror comprises alternating high-index layers and low-index layers.

16. The device recited in claim 15, wherein said low index layers comprise oxidized material.

17. The device recited in claim 14, wherein said top mirror, comprises alternating low index layers and high index layers.

18. The device recited in claim 17, wherein said low index layers are selected from the group consisting of:

oxidized material, low-index dielectric material, relatively-low-index semiconductor material, and any combination thereof.

19. The device recited in claim 17, wherein said high index layers are selected from the group consisting of:

high-index dielectric material, high-index semiconductor material and any combination thereof.

20. The device recited in claim 14, further comprising an aperture disposed between said active region and said top mirror, said aperture having a first and second region.

21. The device recited in claim 20, wherein said first region exhibits high electrical resistance;

and second region and has an electrical resistance lower that said first region.

22. The device recited in claim 20, wherein said first region is oxidized and said second region is oxidized less than said first region.

23. The device recited in claim 14, wherein said resonance wavelength exceeds said peak transition wavelength of said active region by at least 0.010 μ

m.

24. The device recited in claim 14, wherein said device is a VCSEL.

25. The device recited in claim 13, further comprising a grating layer disposed above said second conductive layer, said grating layer having grating lines extending at least partially or completely across said active region to form a grating, said grating defining an optical cavity having a cavity resonance at a resonance wavelength corresponding to a resonance energy;

said resonance wavelength in μ

m, as measured in vacuum, being equal to 1.24 divided by said resonance energy, in electron volts.

26. The device recited in claim 25, wherein said grating lines are shifted by approximately least one quarter wave or a multiple thereof to form a phase shift grating.

27. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0065, and w+y≧

033.

28. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0043, and w+y≧

0.4.

29. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0027, and w+y≧

0.5.

30. The device recited in claim 1, wherein said active region consists essentially of In_y Ga.sub.(1-y) As_1-(w+v) Sb_w N_v, where v≦

0.0068, and w+y≧

0.6.