III-nitride nanowire LED with strain modified surface active region and method of making thereof
A light emitting diode (LED) device includes a semiconductor nanowire core, and an In(Al)GaN active region quantum well shell located radially around the semiconductor nanowire core. The active quantum well shell contains indium rich regions having at least 5 atomic percent higher indium content than indium poor regions in the same shell. The active region quantum well shell has a non-uniform surface profile having at least 3 peaks. Each of the at least 3 peaks is separated from an adjacent one of the at least 3 peaks by a valley, and each of the at least 3 peaks extends at least 2 nm in a radial direction away from an adjacent valley.
1. A nanowire device, comprising:
a semiconductor nanowire core; and
a first semiconductor shell located radially around the semiconductor nanowire core, wherein:
the first semiconductor shell includes a non-uniform InGaN concentration profile along a vertical direction including a first peak in indium concentration and a first valley in indium concentration underneath the first peak; and
indium concentration at the first peak is at least 5 atomic percent greater than indium concentration at the first valley.
2. The device of claim 1 , wherein:
the semiconductor nanowire core comprises a GaN semiconductor core;
the device comprises a light emitting diode (LED) device; and
the first semiconductor shell comprises an active region quantum well shell.
3. The device of claim 2 , further comprising a second semiconductor shell located radially between the semiconductor nanowire core and the first semiconductor shell.
4. The device of claim 1 , wherein the first peak in indium concentration is located at a top end of a sidewall of the first semiconductor shell that generally extends along a direction that is perpendicular to a top surface of a substrate on which the semiconductor nanowire core is located.
5. The device of claim 4 , wherein the sidewall of the first semiconductor shell has a non-uniform surface having a first bulge along a direction away from the semiconductor nanowire core and a first recess along the direction away from the semiconductor nanowire core.
6. The device of claim 5 , wherein:
the first bulge is located in a region of the first peak in indium concentration; and
the first recess is located in a region of the first valley in indium concentration.
7. The device of claim 1 , wherein the non-uniform InGaN concentration profile further comprises:
a second peak in indium concentration underneath the first valley in indium concentration; and
a second valley in indium concentration underneath the second peak in indium concentration.
8. The device of claim 7 , wherein the second peak has a lower atomic percent of indium than the first peak.
9. The device of claim 1 , wherein the non-uniform InGaN concentration profile includes at least three peaks in indium concentration that are vertically spaced apart by at least two valleys in indium concentration.
10. The device of claim 9 , wherein:
the first semiconductor shell has a non-uniform surface having at least three bulges along a direction away from the semiconductor nanowire core; and
each of the at least three bulges is located within a respective one of regions of the at least three peaks in indium concentration.
11. A method of making nanowire device, comprising:
forming a semiconductor nanowire core; and
forming a first semiconductor shell located radially around the semiconductor nanowire core,
wherein:
the first semiconductor shell includes a non-uniform InGaN concentration profile along a vertical direction including a first peak in indium concentration and a first valley in indium concentration underneath the first peak; and
indium concentration at the first peak is at least 5 atomic percent greater than indium concentration at the first valley.
12. The method of claim 11 , wherein:
the semiconductor nanowire core comprises a GaN semiconductor core;
the device comprises a light emitting diode (LED) device; and
the first semiconductor shell comprises an active region quantum well shell.
13. The method of claim 12 , further comprising a second semiconductor shell located radially between the semiconductor nanowire core and the first semiconductor shell.
14. The method of claim 11 , wherein the first peak in indium concentration is located at a top end of a sidewall of the first semiconductor shell that generally extends along a direction that is perpendicular to a top surface of a substrate on which the semiconductor nanowire core is located.
15. The method of claim 14 , wherein the sidewall of the first semiconductor shell has a non-uniform surface having a first bulge along a direction away from the semiconductor nanowire core and a first recess along the direction away from the semiconductor nanowire core.
16. The method of claim 15 , wherein:
the first bulge is located in a region of the first peak in indium concentration; and
the first recess is located in a region of the first valley in indium concentration.
17. The method of claim 11 , wherein the non-uniform InGaN concentration profile further comprises:
a second peak in indium concentration underneath the first valley in indium concentration; and
a second valley in indium concentration underneath the second peak in indium concentration.
18. The method of claim 17 , wherein the second peak has a lower atomic percent of indium than the first peak.
19. The method of claim 11 , wherein the non-uniform InGaN concentration profile includes at least three peaks in indium concentration that are vertically spaced apart by at least two valleys in indium concentration.
20. The method of claim 19 , wherein:
the first semiconductor shell has a non-uniform surface having at least three bulges along a direction away from the semiconductor nanowire core; and
each of the at least three bulges is located within a respective one of regions of the at least three peaks in indium concentration.