Diffusion revealed blocking junction
LEDs and methods of fabrication are described. The LEDs may include a diffusion revealed blocking junction within a cladding layer in order to confine current within an interior of the LED, and mitigate non-radiative recombination at the LED sidewalls.
1. A light emitting diode comprising:
laterally opposite sidewalls;
a first cladding layer spanning between the laterally opposite sidewalls, and doped with a first dopant type;
an active layer over the first cladding layer and spanning between the laterally opposite sidewalls;
a second cladding layer over the active layer and spanning between the laterally opposite sidewalls, and doped with a second dopant type opposite the first dopant type; and
a co-doped region embedded within the first cladding layer and spanning between the laterally opposite sidewalls, and including dopants of the first dopant type and the second dopant type;
a current injection region within the laterally opposite sidewalls; and
a current confinement region laterally surrounding the current injection region, and spanning along the laterally opposite sidewalls, wherein the current confinement region comprises a dopant concentration of the first dopant type extending through the first cladding layer; and
wherein the current confinement region dopant concentration extends through and overlaps the co-doped region to form a net second dopant type blocking junction within the first cladding layer, and the current confinement region dopant concentration surrounds a net first dopant type region of the co-doped region that is within first cladding layer and overlaps the current injection region.
2. The light emitting diode of claim 1 , wherein the first cladding layer is p-type doped.
3. The light emitting diode of claim 2 , wherein the first cladding layer p-type doped with Mg.
4. The light emitting diode of claim 3 , wherein the current confinement region dopant concentration comprises Zn.
5. The light emitting diode of claim 4 , wherein Mg concentration within the first cladding layer is higher in the current injection region than in the current confinement region.
6. The light emitting diode of claim 1 , wherein the first cladding layer comprises a higher p-type dopant concentration in the current injection region than in the current confinement region.
7. The light emitting diode of claim 1 , wherein the first cladding layer is p-type doped, and further comprising:
a bottom confinement layer over the p-type doped first cladding layer, and spanning between the laterally opposite sidewalls and the current injection region; and
a top confinement layer on the active layer, and spanning between the laterally opposite sidewalls and the current injection region.
8. The light emitting diode of claim 7 , wherein the current confinement region dopant concentration extends through the p-type doped first cladding layer, the bottom confinement layer, the active layer, and the top confinement layer.
9. The light emitting diode of claim 1 , wherein:
the current confinement region dopant concentration extends through the active layer;
the active layer comprises a plurality of alternating barrier layers and quantum well layers; and
the current confinement region overlaps an intermixed region of the active layer, which has a higher bandgap than the plurality of the quantum well layers that overlap the current injection region.
10. A display device comprising:
a display substrate;
pixel electrode;
an LED bonded to the pixel electrode, the LED comprising:
laterally opposite sidewalls;
a first cladding layer spanning between the laterally opposite sidewalls, and doped with a first dopant type;
an active layer over the first cladding layer and spanning between the laterally opposite sidewalls;
a second cladding layer over the active layer and spanning between the laterally opposite sidewalls, and doped with a second dopant type opposite the first dopant type; and
a co-doped region embedded within the first cladding layer and spanning between the laterally opposite sidewalls, and including dopants of the first dopant type and the second dopant type;
a current injection region within the laterally opposite sidewalls; and
a current confinement region laterally surrounding the current injection region, and spanning along the laterally opposite sidewalls, wherein the current confinement region comprises a dopant concentration of the first dopant type extending through the first cladding layer; and
wherein the current confinement region dopant concentration extends through and overlaps the co-doped region to form a net second dopant type blocking junction within the first cladding layer, and the current confinement region dopant concentration surrounds a net first dopant type region of the co-doped region that is within first cladding layer and overlaps the current injection region.
11. The light emitting diode of claim 10 , wherein the first cladding layer is p-type doped.
12. The light emitting diode of claim 11 , wherein the first cladding layer p-type doped with Mg.
13. The light emitting diode of claim 12 , wherein the current confinement region dopant concentration comprises Zn.
14. The light emitting diode of claim 13 , wherein Mg concentration within the first cladding layer is higher in the current injection region than in the current confinement region.