Light emitting diode structure
Disclosed is a light emitting diode structure including a Constructive Oxide Contact Structure contact layer. The light emitting diode structure comprises a substrate, a buffer layer formed on the substrate, a lower confinement layer formed on the buffer layer, a light emitting layer formed on the lower confinement layer, an upper confinement layer formed on the light emitting layer, a Constructive Oxide Contact Structure contact layer formed on the upper confinement layer whose conducting type can be P-type, N-type, or I-type, a first electrode, and a second electrode (transparent electrode). The transparent electrode is formed on the Constructive Oxide Contact Structure contact layer as an anode of the light emitting diode. The first electrode is formed on the lower confinement layer and is spaced apart from the light emitting layer, the upper confinement layer, the contact layer, and the transparent electrode. The first electrode is used as a cathode of the light emitting diode.
1. A light emitting diode structure, comprising:
a substrate;
a first semiconductor layer formed directly on the substrate;
a light emitting layer formed directly on the first semiconductor layer;
a second semiconductor layer formed directly on the light emitting layer;
a contact layer formed directly on the second semiconductor layer, wherein the contact layer comprises a first InN layer, an In x Ga 1-x N layer, an In y Ga 1-y N layer, an In z Ga 1-z N layer, and a second InN layer, sequentially stacked in this order from bottom to top on the second semiconductor layer, wherein the band gaps of the layers are decreased in the order of the second semiconductor layer>the In x Ga 1-x N layer>the In z Ga 1-z N layer>the In y Ga 1-y N layer.
2. The structure according to claim 1 , wherein the second semiconductor layer is made of Gallium nitride (GaN).
3. The structure according to claim 2 , wherein the thicknesses of the layers are decreased in the order of the GaN layer>the first InN layer>the In y Ga 1-y N layer>the second InN layer.
4. The structure according to claim 1 , wherein the thickness of the first InN layer is not more than 10 nm, the thickness of the In y Ga 1-y N layer is not more than 5 nm, and the thickness of the second InN layer is not more than 2 nm.
5. The structure according to claim 1 , wherein the contact layer has a thickness between 0.1 to 1,000 nm.
6. The structure according to claim 1 , wherein the substrate is made of an insulating material or a semiconducting material of a conducting type.
7. The structure according to claim 6 , wherein the insulating material is selected from a group comprising Aluminum oxide (Al 2 O 3 , sapphire), Aluminum nitride (AlN), Gallium nitride (GaN), Spinel, Lithium Gallium oxide (LiGaO 3 ), Lithium Aluminum oxide (LiAlO 3 ).
8. The structure according to claim 6 , wherein the semiconducting material is selected from a group comprising Silicon carbide (SiC), Zinc oxide (ZnO), Silicon (Si), Gallium phosphide (GaP), Gallium arsenide (GaAs), Zinc selenium (ZnSe), Indium phosphide (InP), Gallium nitride (GaN) of a Si-doped conducting type.
9. The structure according to claim 1 , further comprising a thin film of a conducting type directly formed on the contact layer.