US 2010/0140651 A1Published application

Diffraction grating light-emitting diode

AssigneeAlps Electric Co., Ltd.

InventorsSusumu NODA, Takashi ASANO, Masayuki FUJITA, Hitoshi KITAGAWA, Toshihide SUTO

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Abstract

The present invention provides a diffraction grating light-emitting diode in which the external quantum efficiency is improved by appropriately setting the period of holes when the holes are two-dimensionally periodically formed. A light-emitting diode is configured by laminating, on a sapphire substrate, an n-type GaN layer, an InGaN/GaN active layer, a p-type GaN layer, and a transparent electrode layer. Further, a large number of holes are two-dimensionally periodically formed in the transparent electrode layer, the p-type GaN layer, the InGaN/GaN active layer, and the n-type GaN layer so as to extend in a direction substantially perpendicular to these layers. Assuming that the non-radiative recombination rate is vs, the arrangement period a of the holes satisfies the following expression: v s  η in ( 0 ) / a < ( F γ - 1 ) 2  π  K  f ( 1 - f )  R sp

Claims3

Dependent claims

A diffraction grating light-emitting diode comprising:

a first semiconductor layer, an active layer, a second semiconductor layer, a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer, which are laminated in order,
wherein a large number of holes are two-dimensionally periodically arranged so as to pass through the active layer and at least one of the first and second semiconductor layers, and assuming that a non-radiative recombination rate is vs, the arrangement period a of the holes is designed to satisfy the following expression:
v
s

η
in
(
0
)
/
a
<
(
F
γ
-
1
)
2

π

K

f
(
1
-
f
)

R
sp
(wherein ηin(0) represents an internal quantum efficiency when holes are not provided, K represents a constant determined by an arrangement state of holes, f represents a two-dimensional filling rate of holes, Rsp represents a spontaneous emission rate when holes are provided, F7 represents an increase ratio of light extraction efficiency of a structure provided with holes to that of a structure not provided with holes).

32 more elements

Dependencies are inferred from the claim text.