Solid state laser device using a selected crystal orientation in non-polar or semi-polar GaN containing materials and methods
View Patent ↗An edge emitting solid state laser and method. The laser comprises at least one AlInGaN active layer on a bulk GaN substrate with a non-polar or semi-polar orientation. The edges of the laser comprise {1 1−2±6} facets. The laser has high gain, low threshold currents, capability for extended operation at high current densities, and can be manufactured with improved yield. The laser is useful for optical data storage, projection displays, and as a source for general illumination.
1. A laser device comprising:
a gallium and nitrogen containing crystalline material having a nonpolar m-plane surface region;
a laser cavity formed within a portion of the gallium and nitrogen containing crystalline material, the laser cavity being characterized by a length extending from a first end to a second opposite end;
a first facet provided on the first end; and
a second facet provided on the second end;
wherein the length of the laser cavity is along a direction that is at an angle measured in degrees from a [0001] direction of the gallium and nitrogen containing crystalline material; and
wherein the length of the laser cavity is at an angle of between about 0.3 degrees to about 30 degrees or between about −0.3 degrees to about −30 degrees from a [0001] direction of the gallium and nitrogen containing crystalline material.
2. The device of claim 1 , wherein the gallium and nitrogen containing crystalline material comprises gallium nitride.
3. The device of claim 1 , wherein the nonpolar m-plane surface region is an off-cut from an m-plane, within +/−10 degrees toward a c-plane, and/or within +/ −10 degrees toward an a-plane.
4. The device of claim 1 , wherein the first facet and the second facet have an orientation within ±5 degrees of a {1 1 −2 6} crystallographic plane or within ±5 degrees of a {1 1 −2 6} crystallographic plane of the gallium nitride containing crystalline material.
5. The device of claim 1 , wherein the first facet is substantially parallel to the second facet.
6. The device of claim 1 , further comprising an active region within the laser cavity.
7. The device of claim 6 , wherein the active region comprises at least a quantum well region.
8. The device of claim 1 , wherein the first facet and the second facet are formed by mechanically cleaving.
9. The device of claim 1 , wherein the first facet and the second facet are characterized by a surface roughness less than about 1 nm over a 25 micron square area.
10. A method of forming a laser device comprising:
providing a gallium and nitrogen containing crystalline material having a nonpolar m-plane surface region;
providing a laser cavity formed within a portion of the gallium and nitrogen containing crystalline material, the laser cavity being characterized by a length extending from a first end to a second opposite end;
providing a first facet on the first end; and
providing a second facet on the second end;
wherein the length of the laser cavity is along a direction that is at an angle measured in degrees from a [0001] direction of the gallium and nitrogen containing crystalline material; and
wherein the length of the laser cavity is at an angle of between about 0.3 degrees to about 30 degrees or between about −0.3 degrees to about −30 degrees from a [0001] direction of the gallium and nitrogen containing crystalline material.
11. The method of claim 10 , wherein the gallium and nitrogen containing crystalline material comprises gallium nitride.
12. The method of claim 10 , wherein the nonpolar m-plane surface region is an off-cut from an m-plane, within +/−10 degrees toward a c-plane, and/or within +/−10 degrees toward an a-plane.
13. The method of claim 10 , wherein the first facet and the second facet have an orientation within ±5 degrees of a {1 1 −2 6} crystallographic plane or within ±5 degrees of a {1 1 −2 6} crystallographic plane of the gallium nitride containing crystalline material.
14. The method of claim 10 , wherein the first facet is substantially parallel to the second facet.
15. The method of claim 10 , wherein providing the first facet and providing the second facet comprises mechanically cleaving.
16. The method of claim 10 , wherein the first facet and the second facet are characterized by a surface roughness less than about 1 nm over a 25 micron square area.