Reduction of surface recombination losses in micro-LEDs
Disclosed herein are systems and methods for reducing surface recombination losses in micro-LEDs. In some embodiments, a method includes reducing a lateral carrier diffusion in an outer region of a semiconductor layer by implanting ions in the outer region of the semiconductor layer. The semiconductor layer includes an active light emitting layer. An outcoupling surface of the semiconductor layer has a diameter of less than 10 μm. The outer region of the semiconductor layer extends from an outer surface of the semiconductor layer to a central region of the semiconductor layer that is shaded by a mask during the implanting of the ions.
1. A method comprising:
reducing a lateral carrier diffusion in an outer region of a semiconductor layer by implanting ions in the outer region of the semiconductor layer, wherein:
the semiconductor layer comprises an active light emitting layer,
a light outcoupling surface of the semiconductor layer has a diameter of less than 10 μm,
the outer region of the semiconductor layer extends from an outer surface of the semiconductor layer to a central region of the semiconductor layer that is shaded by a mask during the implanting of the ions, and
the semiconductor layer further comprises an n-side semiconductor layer adjacent to the light outcoupling surface and a p-side semiconductor layer opposite to the active light emitting layer.
2. The method of claim 1 , wherein the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the p-side semiconductor layer.
3. The method of claim 1 , wherein the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the active light emitting layer.
4. The method of claim 1 , wherein the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the n-side semiconductor layer.
5. The method of claim 1 , wherein the ions are implanted at an angle between 0° and 7° with respect to an axis that is normal to a plane of the mask.
6. The method of claim 1 , wherein the lateral carrier diffusion in the outer region of the semiconductor layer is reduced to less than 1 cm 2 /s.
7. The method of claim 1 , wherein the mask comprises at least one of a metal, a resist, or a hard mask.
8. The method of claim 7 , wherein the metal has a thickness of less than 1000 nm, the resist has a thickness of less than 2500 nm, and the hard mask has a thickness of less than 800 nm.
9. The method of claim 1 , wherein the ions comprise hydrogen ions or helium ions.
10. The method of claim 9 , wherein the ions have an implantation energy between 20 keV and 140 keV.
11. The method of claim 9 , wherein an implantation dose of the ions is between 1×10 14 cm −2 and 1×10 16 cm −2 .
12. A light-emitting diode comprising:
a semiconductor layer comprising an active light emitting layer, wherein:
a light outcoupling surface of the semiconductor layer has a diameter of less than 10 μm,
a lateral carrier diffusion in an outer region of the semiconductor layer is less than a lateral carrier diffusion in a central region of the semiconductor layer,
the outer region of the semiconductor layer comprises ions that are implanted in the outer region of the semiconductor layer, and
the semiconductor layer further comprises an n-side semiconductor layer adjacent to the light outcoupling surface and a p-side semiconductor layer opposite to the active light emitting layer.
13. The light-emitting diode of claim 12 , wherein the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the p-side semiconductor layer.
14. The light-emitting diode of claim 12 , wherein the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the active light emitting layer.
15. The light-emitting diode of claim 12 , wherein the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the n-side semiconductor layer.
16. The light-emitting diode of claim 12 , wherein the ions comprise hydrogen ions or helium ions.
17. The light-emitting diode of claim 12 , wherein the lateral carrier diffusion in the outer region of the semiconductor layer is less than 1 cm 2 /s.
18. A light-emitting diode comprising:
a semiconductor layer comprising an active light emitting layer, wherein:
a light outcoupling surface of the semiconductor layer has a diameter of less than 10 μm,
a lateral carrier diffusion in an outer region of the semiconductor layer is less than a lateral carrier diffusion in a central region of the semiconductor layer,
the outer region of the semiconductor layer comprises ions that are implanted in the outer region of the semiconductor layer, and
the lateral carrier diffusion in the outer region of the semiconductor layer is less than 1 cm 2 /s.
19. The light-emitting diode of claim 18 , wherein:
the semiconductor layer further comprises an n-side semiconductor layer adjacent to the light outcoupling surface and a p-side semiconductor layer opposite to the active light emitting layer, and
the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the p-side semiconductor layer.
20. The light-emitting diode of claim 18 , wherein:
the semiconductor layer further comprises an n-side semiconductor layer adjacent to the light outcoupling surface and a p-side semiconductor layer opposite to the active light emitting layer, and
the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the active light emitting layer.
21. The light-emitting diode of claim 18 , wherein:
the semiconductor layer further comprises an n-side semiconductor layer adjacent to the light outcoupling surface and a p-side semiconductor layer opposite to the active light emitting layer, and
the ions are implanted from a top surface of the p-side semiconductor layer to a depth within the n-side semiconductor layer.