Blue and green laser diodes with gallium nitride or indium gallium nitride cladding laser structure

• US 20060126688A1
• Filed: 10/28/2005
• Published: 06/15/2006
• Est. Priority Date: 12/14/2004
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Kneissl, Michael A.
• Granted Patent: US 7,751,455 B2
• Time in Patent Office: Days
• US Class Current: 372/43.10
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 2301/18 Semiconductor lasers with special structural design for influencing the near- or far-field
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/0421 characterised by the semiconducting contacting layers electrodes H01S5/0425
• CPC Class Codes: H01S 5/2004 Confining in the direction perpendicular to the layer structure
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/3054 p-doping
• CPC Class Codes: H01S 5/3211 characterised by special cladding layers, e.g. details on band-discontinuities
• CPC Class Codes: H01S 5/3213 asymmetric clading layers
• CPC Class Codes: H01S 5/3219 explicitly Al-free cladding layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A novel indium gallium nitride laser diode is described. The laser uses indium in either the waveguide layers and/or the cladding layers. It has been found that InGaN waveguide or cladding layers enhance optical confinement with very small losses. Furthermore, the use of InGaN waveguide or cladding layers can improve the structural integrity of active region epilayers because of reduced lattice mismatch between waveguide layers and the active region.

Claims

1. A semiconductor laser comprising:

an active region including at least one quantum well containing indium, gallium and nitride, the active region having a first side and a second side; and

, a first waveguide layer immediately adjacent to the first side, the first waveguide layer including indium, gallium and nitride.

2. The semiconductor laser of claim 1 further comprising:

a second waveguide layer adjacent to the second side.

3. The semiconductor laser of claim 2 wherein the second waveguide layer includes indium, gallium and nitride.

4. The semiconductor laser of claim 3 wherein the first waveguide layer and the second waveguide layer are symmetric.

5. The semiconductor laser of claim 2 wherein the first waveguide layer and the second waveguide layer are asymmetric.

6. The semiconductor laser of claim 2 wherein the second waveguide layer includes aluminum, gallium and nitride.

7. The semiconductor laser of claim 1 wherein the first cladding layer is at least 20 nm thick.

8. The semiconductor laser of claim 1 further comprising:

a tunnel barrier layer immediately adjacent to the second side of the active region; and

,

a second waveguide layer immediately adjacent to an opposite side of the tunnel barrier layer.

9. The semiconductor laser of claim 2 further-comprising:

a first cladding layer adjacent the first waveguide layer; and

,

a second cladding layer adjacent the second waveguide layer.

10. The semiconductor laser of claim 9 wherein the first cladding layer includes gallium and nitride.

11. The semiconductor laser of claim 10 wherein the first cladding layer includes indium, gallium and nitride.

12. The semiconductor laser of claim 11 wherein the second cladding layer includes indium gallium nitride.

13. The semiconductor laser of claim 1 further comprising:

a thin current barrier layer between the active region and the first waveguide layer.

14. The semiconductor laser of claim 13 wherein the thin current barrier layer is less than 30 nm thick.

15. An indium gallium nitride semiconductor laser comprising:

an active region including multiple quantum wells;

a first optical confinement region on a first side of the active region; and

,

a second optical confinement region on a second side of the active region, at least one of the first optical confinement region and the second optical confinement region including indium, gallium and nitride.

16. The indium nitride semiconductor laser of claim 15 wherein the first optical confinement region includes an indium gallium nitride waveguide layer.

17. The indium gallium nitride semiconductor laser of claim 15 wherein the first optical confinement region includes an indium gallium nitride cladding layer.

18. The indium gallium nitride semiconductor laser of claim 15 further comprising:

a conducting layer including gallium and nitride, the first optical confinement region formed over the conducting layer.

19. The indium gallium nitride semiconductor laser of claim 15 wherein the indium gallium nitride semiconductor laser outputs light between a wavelength of 440 nm and 580 nm.

20. The indium gallium nitride semiconductor laser of claim 15 wherein a metal electrode is deposited over the second optical confinement region.

21. The indium gallium nitride semiconductor laser of claim 15 wherein the first optical confinement region includes an indium gallium nitride waveguide having a thickness greater than 20 nm.

22. An indium gallium nitride semiconductor laser comprising:

an active region including indium gallium nitride multiple quantum wells;

a first indium gallium nitride waveguide layer on a first side of the active region; and

,

a second indium gallium nitride waveguide layer on a second side of the active region,

a first indium gallium nitride cladding layer adjacent the first waveguide layer; and

,

a second indium gallium nitride cladding layer adjacent the second waveguide layer.

23. The semiconductor laser of claim 22 including further comprising:

a current confinement layer positioned between the second waveguide layer and the second cladding layer.

24. The semiconductor laser of claim 22 wherein the current confinement layer includes GaN.

25. The semiconductor laser of claim 22 wherein the current confinement layer is Mg doped.

26. The semiconductor laser of claim 22 wherein the current confinement layer is between 5 nm and 40 nm.

27. The semiconductor laser of claim 22 wherein the indium mole fraction in the quantum well is between 20% and 50%.

28. The semiconductor laser of claim 22 wherein the thickness of the quantum well is between 2 nm and 20 nm.