Nitride-based semiconductor light emitting diode

1. A nitride-based semiconductor LED, comprising:

a substrate having a rectangle shape and of which a ratio of a width and a length of the substrate is equal to or more than 1.5;

an n-type nitride semiconductor layer disposed on the substrate and composed of an n-type semiconductor material having a compositional formula of In X Al Y Ga 1-X-Y N (0≦X, 0≦Y, and X+Y≦1);

an active layer and a p-type nitride semiconductor layer sequentially disposed on a predetermined region of the n-type nitride semiconductor layer, the active layer being composed of a semiconductor material having a compositional formula of In X Al Y Ga 1-X-Y N (0≦X, 0≦Y, and X+Y≦1), the p-type nitride semiconductor layer being composed of a p-type semiconductor material having a compositional formula of In X Al Y Ga 1-X-Y N (0≦X, 0≦Y, and X+Y≦1);

a transparent electrode disposed on the p-type nitride semiconductor layer;

a p-electrode pad disposed on the transparent electrode; and

an n-electrode pad disposed on the n-type nitride semiconductor layer, wherein:

the p-electrode pad, devoid of any elongated protrusion or any auxiliary electrode, is spaced apart from an outer edge line of the p-type nitride semiconductor layer by a distance of 50 to 200 μm, such that a uniform luminous effect is obtained in the entire LED, the center of the outer edge line of the p-type nitride semiconductor layer intersects with a straight line that connects a center of the p-electrode pad and a center of the n-electrode pad, and

the n-type semiconductor layer substantially surrounds the n-electrode.

2. The nitride-based semiconductor LED according to claim 1 , wherein the n-type nitride semiconductor layer is a GaN layer or GaN/AlGaN layer doped with any one n-type conductive impurity selected from the group consisting of Si, Ge, and Sn,

the p-type nitride semiconductor layer is a GaN layer or GaN/AlGaN layer doped with any one p-type conductive impurity selected from the group consisting of Mg, Zn, and Be, and

the active layer is composed of an InGaN/GaN layer with a multi-quantum well structure.

3. The nitride-based semiconductor LED according to claim 1 , wherein the p-electrode pad and the n-electrode pad are formed of Au or Au/Cr.

4. The nitride-based semiconductor LED according to claim 1 , wherein the distance between the p-electrode and the outer edge line of the p-type nitride semiconductor layer is longer that a distance between the n-electrode and another outer edge line of the p-type nitride semiconductor layer.

5. The nitride-based semiconductor LED according to claim 1 , further comprising a buffer layer that is interposed between the substrate and the n-type nitride semiconductor layer,

wherein the buffer layer is composed of AlN/GaN.

6. A nitride-based semiconductor LED, comprising:

a substrate having a rectangle shape and of which a ratio of a width and a length of the substrate is equal to or more than 1.5;

an n-type nitride semiconductor layer disposed on the substrate and composed of an n-type semiconductor material having a compositional formula of In X Al Y Ga 1-X-Y N (0≦X, 0≦Y, and X+Y≦1);

an active layer and a p-type nitride semiconductor layer, sequentially disposed on a predetermined region of the n-type nitride semiconductor layer, the active layer being composed of a semiconductor material having a compositional formula of In X Al Y Ga 1-X-Y N (0≦X, 0≦Y, and X+Y≦1), the p-type nitride semiconductor layer being composed of a p-type semiconductor material having a compositional formula of In X Al Y Ga 1-X-Y N (0≦X, 0≦Y, and X+Y≦1);

a transparent electrode disposed on the p-type nitride semiconductor layer;

a p-electrode pad disposed on the transparent electrode, a center of an outer edge line of a p-type nitride semiconductor layer being intersected by a straight line that connects a center of the p-electrode pad and a center of the n-electrode pad, wherein the p-electrode pad is spaced apart from the outer edge line of the p-type nitride semiconductor layer by a distance of 50 to 200 μm, such that a uniform luminous effect is obtained in the entire LED; and

an n-electrode pad that is disposed on the n-type nitride semiconductor layer,

wherein the n-type semiconductor layer substantially surrounds the n-electrode.

7. A backlight unit including the nitride-based semiconductor LED of claim 1 or 6 .

8. A lighting device including the nitride-based semiconductor LED of claim 1 or 6 .

9. The nitride-based semiconductor LED according to claim 6 , further comprising a buffer layer that is interposed between the substrate and the n-type nitride semiconductor layer,

wherein the buffer layer is composed of AlN/GaN.