Devices comprising distributed bragg reflectors and methods of making the devices
A method for making a device. The method comprises forming a buffer layer on a substrate; forming a periodically doped layer on the buffer layer; forming one or more wires on the periodically doped layer, the wires being chosen from nanowires and microwires; and introducing porosity into the periodically doped layer to form a porous distributed Bragg reflector (DBR). Various devices that can be made by the method are also disclosed.
1. A method for making a device, comprising:
forming a buffer layer on a silicon substrate;
forming a periodically doped layer on the buffer layer;
forming one or more nanowires on the periodically doped layer; and
introducing porosity into the periodically doped layer to form a porous distributed Bragg reflector (DBR).
2. The method of claim 1 , wherein the buffer layer comprises AlN.
3. The method of claim 1 , wherein the one or more nanowires comprise a Group III-V semiconductor.
4. The method of claim 3 , wherein the Group III-V semiconductor is GaN.
5. The method of claim 1 , wherein forming the periodically doped layer comprises depositing a first blanket layer comprising a ternary alloy and then etching the first blanket layer.
6. The method of claim 5 , wherein forming the one or more nanowires comprises depositing a second blanket layer comprising a gain material on the first blanket layer and then etching the second blanket layer prior to etching the first blanket layer.
7. The method of claim 1 , wherein forming the periodically doped layer comprises patterning the substrate and then selectively depositing a patterned layer comprising a ternary alloy.
8. The method of claim 7 , wherein forming the one or more nanowires comprises selectively depositing a material on the patterned layer comprising the ternary alloy.
9. The method of claim 1 , further comprising forming a second periodically doped layer on exposed sides of the nanowire and introducing porosity into the second periodically doped layer.
10. The method of claim 1 , further comprising forming an active region comprising one or more quantum wells on the one or more nanowires.
11. A device, comprising:
a buffer layer on a silicon substrate;
a distributed Bragg reflector (DBR) on the buffer layer, the DBR comprising a periodically doped layer comprising alternating doped and undoped layers, the doped layers being porous; and
one or more nanowires on the DBR.
12. The device of claim 11 , wherein the buffer layer comprises AlN.
13. The device of claim 11 , wherein the one or more nanowires comprise a Group III-V semiconductor.
14. The device of claim 13 , wherein the Group III-V semiconductor is GaN.
15. The device of claim 11 , wherein the periodically doped layer comprises a ternary alloy.
16. The device of claim 15 , wherein the ternary alloy is Al x Ga 1-x N.
17. The device of claim 15 , wherein the DBR comprises sidewalls and a metal layer is on the sidewalls of the DBR.
18. The device of claim 11 , wherein the one or more nanowires comprise a Group III-nitride.
19. The device of claim 11 , further comprising a second distributed Bragg reflector (DBR) on exposed sides of the nanowire, the second DBR comprising alternating doped and undoped layers, the doped layers being porous.
20. The device of claim 11 , further comprising an active region comprising quantum wells on the nanowire.
21. A method for making a device, comprising:
forming a buffer layer on a substrate;
forming a periodically doped layer on the buffer layer;
forming one or more wires on the periodically doped layer, the wires being chosen from nanowires and microwires; and
introducing porosity into the periodically doped layer to form a porous distributed Bragg reflector (DBR).
22. The method of claim 21 , wherein the one or more wires have a diameter ranging from about 100 nanometers to about 5 microns.
23. The method of claim 21 , wherein the periodically doped layer comprises at least one material chosen from AlInGaN, AlInGaAs, Al x Ga 1-x N, In x Ga 1-x N, Al x Ga 1-x As and In x Ga 1-x As where X ranges from 0 to 1.
24. The method of claim 21 , wherein the device is a white LED and the DBR comprises two or more DBRs with different peak reflectance wavelengths.
25. The method of claim 24 , at least one of the two or more DBRs has a peak reflectance wavelengths in one of the blue, green, and red spectrums.
26. The method of claim 21 , wherein the one or more wires comprise a material chosen from Al x Ga 1-x N, In x Ga 1-x N, AlInGaN, GaN, AlN, InN, Al x Ga 1-x As, In x Ga 1-x As, AlInGaAs, GaAs, InGaAs, InAs and AlGaAs, where X ranges from 0 to 1.