Tunnel junction ultraviolet light emitting diodes with enhanced light extraction efficiency
An example tunnel junction ultraviolet (UV) light emitting diode (LED) is described herein. The UV LED can include a mesa structure having at least one of: an n-doped bottom contact region, a p-doped region, and a tunnel junction arranged in contact with the p-doped region. Additionally, a geometry of the mesa structure can be configured to increase respective efficiencies of extracting transverse-electric (TE) polarized light and transverse-magnetic (TM) polarized light from the tunnel junction UV LED. The mesa structure can be configured such that an emitted photon travels less than 10 μm before reaching the inclined sidewall.
1. A tunnel junction ultraviolet (UV) light emitting diode (LED), comprising: a mesa structure comprising at least one of: an n-doped bottom contact region, a p-doped region, and a tunnel junction arranged in contact with the p-doped region, wherein a geometry of the mesa structure is configured to increase respective efficiencies of extracting transverse-electric (TE) polarized light and transverse-magnetic (TM) polarized light from the tunnel junction UV LED, wherein the mesa structure is configured such that an emitted photon travels less than 10 μm before reaching an inclined sidewall of the mesa structure, wherein the inclined sidewall is formed in at least a portion of the p-doped region, and wherein the tunnel junction is arranged below the p-doped region;
an active region arranged in contact with at least a portion of the inclined sidewall of the mesa structure;
an n-doped top contact region, wherein the active region is arranged between the p-doped region and the n-doped top contact region, and wherein the n-doped top contact region is arranged on the inclined sidewall; and
a reflective material arranged on at least a portion of the inclined sidewall of the mesa structure.
2. The tunnel junction UV LED of claim 1 , wherein the mesa structure has an elongated shape.
3. The tunnel junction UV LED of claim 2 , wherein an aspect ratio of the mesa structure is greater than 5.
4. The tunnel junction UV LED of claim 2 , wherein the mesa structure comprises at least two inclined sidewalls.
5. The tunnel junction UV LED of claim 2 , wherein the elongated shape of the mesa structure forms a straight pattern, a zig zag pattern, a curved pattern, a sinusoidal pattern, or a spiral pattern.
6. The tunnel junction UV LED of claim 1 , wherein the mesa structure has a truncated pyramid shape or a truncated cone shape.
7. The tunnel junction UV LED of claim 1 , further comprising a dielectric material arranged on at least a portion of the inclined sidewall of the mesa structure.
8. The tunnel junction UV LED of claim 1 , wherein the inclined sidewall comprises a plurality of portions having different angles of inclination.