Light emitting diode having photonic crystal structure and method of fabricating the same
View Patent ↗Disclosed are a light emitting diode (LED) having a photonic crystal structure and a method of fabricating the same. An LED comprises a support substrate, a lower semiconductor layer positioned on the support substrate, an upper semiconductor layer positioned over the lower semiconductor layer, an active region positioned between the lower and upper semiconductor layers, and a photonic crystal structure embedded in the lower semiconductor layer. The photonic crystal structure may prevent the loss of the light advancing toward the support substrate and improve the light extraction efficiency.
1. A light emitting diode (LED), comprising:
a support substrate;
a first semiconductor layer disposed on the support substrate;
a second semiconductor layer disposed on the first semiconductor layer;
an active region disposed between the first and second semiconductor layers; and
a photonic crystal structure embedded in the first semiconductor layer,
wherein:
the first semiconductor layer comprises a p-type contact layer and a p-type clad layer;
the photonic crystal structure comprises a pattern of voids disposed on the support substrate;
the pattern of voids are disposed at an interface between the p-type contact layer and the p-type clad layer; and
a width and a height of each void of the pattern of voids is within a range of 50 to 200 nm, and a distance between two adjacent voids is within a range of 50 nm to 1 μm.
2. The LED of claim 1 , wherein the second semiconductor layer comprises an n-type contact layer.
3. The LED of claim 2 , wherein the active region comprises an AlGaN well layer, and the p-type contact layer comprises a p-type GaN layer or a p-type AlInGaN layer.
4. The LED of claim 1 , wherein the first semiconductor layer comprises at least one AlGaN layer disposed between the voids and the active region.
5. The LED of claim 4 , wherein the p-contact layer covers the voids.
6. The LED of claim 1 , wherein the second semiconductor layer comprises a roughened surface.
7. The LED of claim 6 , wherein the roughened surface comprises a pattern of recesses.
8. The LED of claim 6 , wherein the second semiconductor layer comprises an n-type AlGaN layer.
9. The LED of claim 3 , wherein the LED is configured to emit deep UV light having a wavelength in the range of 240 to 365 nm through the AlGaN well layer.