Group III nitride semiconductor light-emitting device
First Claim
1. A Group III nitride semiconductor light-emitting device, comprising:
- a sapphire substrate; and
a layered structure comprising a light-emitting layer provided on the sapphire substrate and including a Group III nitride semiconductor,wherein the sapphire substrate comprises a periodic structure on a surface on a side with the layered structure,wherein the periodic structure comprises at least one of dents and mesas arranged in a two-dimensional periodic array with a period which provides a dense honeycomb structure, in which a distance from any one of the dents or mesas to each of six adjacent dents or mesas is equal, and the periodic structure generates a light intensity interference pattern with a six-fold rotational symmetry for light emitted from the light-emitting layer, andwherein the period is from 2.25 μ
m to 3.25 μ
m, the periodic structure has a height of 0.5 μ
m to 2 μ
m, a side surface angle between a side wall and a base of one of the dents or mesas is 45°
to 75°
, a relative light intensity falls within a range of 1 to 0.9 when an emission angle of light emitted from the light-emitting device falls within a range of −
45°
to 45°
.
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Accused Products
Abstract
The present invention provides a Group III nitride semiconductor light-emitting device exhibiting high-intensity light output in a specific direction and improved light extraction performance. The Group III nitride semiconductor light-emitting device comprises a sapphire substrate, and a layered structure having a light-emitting layer provided on the sapphire substrate and formed of a Group III nitride semiconductor. On the surface on the layered structure side of the sapphire substrate, a two-dimensional periodic structure of mesas is formed with a period which generates a light intensity interference pattern for the light emitted from the light-emitting layer. The light reflected by or transmitted through the two-dimensional periodic structure has an interference pattern. Therefore, the light focused on a region where the light intensity is high in the interference pattern can be effectively output to the outside, resulting in the improvement of light extraction performance as well as the achievement of desired directional characteristics.
19 Citations
12 Claims
-
1. A Group III nitride semiconductor light-emitting device, comprising:
-
a sapphire substrate; and a layered structure comprising a light-emitting layer provided on the sapphire substrate and including a Group III nitride semiconductor, wherein the sapphire substrate comprises a periodic structure on a surface on a side with the layered structure, wherein the periodic structure comprises at least one of dents and mesas arranged in a two-dimensional periodic array with a period which provides a dense honeycomb structure, in which a distance from any one of the dents or mesas to each of six adjacent dents or mesas is equal, and the periodic structure generates a light intensity interference pattern with a six-fold rotational symmetry for light emitted from the light-emitting layer, and wherein the period is from 2.25 μ
m to 3.25 μ
m, the periodic structure has a height of 0.5 μ
m to 2 μ
m, a side surface angle between a side wall and a base of one of the dents or mesas is 45°
to 75°
, a relative light intensity falls within a range of 1 to 0.9 when an emission angle of light emitted from the light-emitting device falls within a range of −
45°
to 45°
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
Specification