Nano-photonics reflector for LED emitters
A system, method and device for use as a reflector for a light emitting diode (LED) are disclosed. The system, method and device include a first layer designed to reflect transverse-electric (TE) radiation emitted by the LED, a second layer designed to block transverse-magnetic (TM) radiation emitted from the LED, and a plurality of ITO layers designed to operate as a transparent conducting oxide layer. The first layer may be a one-dimension (1D) distributed Bragg reflective (DBR) layer. The second layer may be a two-dimension (2D) photonic crystal (PhC), a three-dimension (3D) PhC, and/or a hyperbolic metamaterial (HMM). The 2D PhC may include horizontal cylinder bars, vertical cylinder bars, or both. The system, method and device may include a bottom metal reflector that may be Ag free and may act as a bonding layer.
1. A light emitting diode (LED) device comprising:
a light emitting semiconductor structure that in operation emits light having a peak wavelength,
a reflective structure comprising:
a distributed Bragg reflector (DBR) configured to reflect light emitted by the light emitting semiconductor structure at the peak wavelength and incident with transverse-electric (TE) polarization on the reflective structure; and
a reflective layer configured to reflect light emitted by the light emitting semiconductor structure at the peak wavelength and incident with transverse-magnetic (TM) polarization on the reflective structure, the reflective layer comprising one or more of SiO 2 , TiO 2 , MgF, and Nb 2 O 5 ; and
a bottom metal reflector that is Ag free.
2. The LED device of claim 1 , wherein the light emitting semiconductor structure is a III/V direct bandgap semiconductor.
3. The LED device of claim 1 , wherein the bottom metal reflector comprises Au.
4. The LED device of claim 1 , wherein the bottom metal reflector is in direct contact with the reflective layer.
5. The LED device of claim 1 , wherein the bottom metal reflector is not in direct contact with the DBR nor the light emitting semiconductor structure.
6. The LED device of claim 1 , wherein the reflective layer is between the DBR and the bottom metal reflector.
7. The LED device of claim 1 , further comprising a transparent conducting metal oxide layer adjacent to the light emitting semiconductor structure.
8. The LED device of claim 7 , wherein the transparent conducting metal oxide layer is an ITO layer.
9. The LED device of claim 1 , wherein the DBR is disposed between the reflective layer and the light emitting semiconductor structure.
10. The LED device of claim 1 , wherein the reflective layer is disposed between the DBR and the light emitting semiconductor structure.
11. The LED device of claim 1 , wherein the reflective layer comprises metal and dielectric.
12. The LED device of claim 1 , wherein the reflective layer and the DBR are approximately a same thickness.
13. A light emitting diode (LED) device comprising:
a light emitting semiconductor structure that in operation emits light having a peak wavelength,
a reflective structure comprising:
a distributed Bragg reflector (DBR) configured to reflect light emitted by the light emitting semiconductor structure at the peak wavelength and incident with S polarization on the reflective structure; and
a reflective layer in direct contact with the DBR and configured to reflect light emitted by the light emitting semiconductor structure at the peak wavelength and incident with P polarization on the reflective structure;
wherein the DBR is disposed between the reflective layer and the light emitting semiconductor structure.
14. The LED device of claim 13 , wherein the light emitting semiconductor structure is a III/V semiconductor.
15. The LED device of claim 13 , further comprising a transparent conducting metal oxide layer adjacent to the light emitting semiconductor structure.
16. The LED device of claim 13 , wherein the reflective layer is disposed between the DBR and the light emitting semiconductor structure.
17. A light emitting diode (LED) device comprising:
a light emitting semiconductor structure that in operation emits light having a peak wavelength,
a transparent conducting metal oxide layer adjacent to the light emitting semiconductor structure; and
a reflective structure comprising:
a distributed Bragg reflector (DBR) having a first thickness and configured to reflect light emitted by the light emitting semiconductor structure at the peak wavelength and incident with transverse-electric (TE) polarization on the reflective structure; and
a reflective layer configured to reflect light emitted by the light emitting semiconductor structure at the peak wavelength and incident with TM polarization on the reflective structure, the reflective layer having a second thickness that is a same as or thinner than the first thickness of the DBR.