Nitride semiconductor light emitting element having light emitting layer including INxGa1-xN well layer and LED system
View Patent ↗A nitride semiconductor light emitting element includes a light emitting layer. The light emitting layer includes an In x Ga 1-x N well layer (0<x≦1) having a principal surface that is an m-plane. A profile in a depth direction (depth profile) of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks. Values of the In composition ratios x at the respective plurality of peaks are different from one another.
1. A nitride semiconductor light emitting element comprising a light emitting layer, wherein:
the light emitting layer includes an In x Ga 1-x N well layer, where 0<x≦1, having a principal surface that is an m-plane;
a depth profile of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks;
values of the In composition ratios x at the respective plurality of peaks are different from one another;
a temperature coefficient of a wavelength of light generated in the light emitting layer is zero at any one of temperatures from 243 K to 353 K; and
a difference between a shorter one of the wavelength at 243 K and the wavelength at 353 K, and the wavelength at a temperature at which the temperature coefficient is zero is 2 nm or less.
2. An LED system comprising a plurality of the nitride semiconductor light emitting elements of claim 1 , wherein:
the plurality of the nitride semiconductor light emitting elements are connected in parallel; and
a thickness W of the In x Ga 1-x N well layer is the same throughout the plurality of the nitride semiconductor light emitting elements, W is 7 nm or more, and LED system is operated under a state in which the following relational expression is satisfied, [Math. 29 ]
10.42
×
W
[
nm
]
-
81.3
≤
I_total
S_well
_total
[
A
/
cm
2
]
≤
10.42
×
W
[
nm
]
-
61.3
where W is the thickness of the In x Ga 1-x N well layer, I_total is an operating current value of the entire plurality of the nitride semiconductor light emitting elements that are connected in parallel, S_well_total is a total of areas of the In x Ga 1-x N well layers in the top view of the respective plurality of the nitride semiconductor light emitting elements.
3. An LED system comprising N nitride semiconductor light emitting elements of claim 1 , where N is an integer of 2 or more, wherein:
the N nitride semiconductor light emitting elements are connected in parallel; and
a thickness W and an area S_well are the same throughout the N nitride semiconductor light emitting elements, W is 7 nm or more, and the LED system is operated under a state in which the following relational expression is satisfied, [Math. 30 ]
10.42
×
W
[
nm
]
-
81.3
≤
I_total
N
×
S_well
[
A
/
cm
2
]
≤
10.42
×
W
[
nm
]
-
61.3
where W is the thickness of the In x Ga 1-x N well layer, S_well is the area of the In x Ga 1-x N well layer in the top view of the N nitride semiconductor light emitting elements, and I_total is an operating current value of the entire N nitride semiconductor light emitting elements that are connected in parallel.
4. An LED system comprising:
one or a plurality of the nitride semiconductor light emitting elements of claim 1 ; and
a current supply portion for supplying current to the one or a plurality of the nitride semiconductor light emitting elements so that a temperature coefficient of a wavelength of light generated in the light emitting layer is zero at any one of temperatures from 243 K to 353 K, and so that a difference between a shorter one of the wavelength at 243 K and the wavelength at 353 K, and the wavelength at a temperature at which the temperature coefficient is zero is 2 nm or less.
5. A nitride semiconductor light emitting element comprising a light emitting layer, wherein:
the light emitting layer includes an In x Ga 1-x N well layer 0<x≦1, having a principal surface that is an m-plane;
a depth profile of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks;
values of the In composition ratios x at the respective plurality of peaks are different from one another;
a temperature coefficient of a wavelength of light generated in the light emitting layer is zero at any one of temperatures from 233 K to 393 K; and
a difference between a shorter one of the wavelength at 233 K and the wavelength at 393 K, and the wavelength at a temperature at which the temperature coefficient is zero is 5 nm or less.
6. An LED system comprising:
one or a plurality of the nitride semiconductor light emitting elements of claim 5 ; and
a current supply portion for supplying current to the one or a plurality of the nitride semiconductor light emitting elements so that a temperature coefficient of a wavelength of light generated in the light emitting layer is zero at any one of temperatures from 233 K to 393 K, and so that a difference between a shorter one of the wavelength at 233 K and the wavelength at 393 K, and the wavelength at a temperature at which the temperature coefficient is zero is 5 nm or less.
7. A nitride semiconductor light emitting element comprising a light emitting layer, wherein:
the light layer includes an In x Ga 1-x N well layer, where 0<x≦1, having a principal surface that is an m-plane;
a depth profile of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks;
values of the In composition ratios x at the respective plurality of peaks are different from one another;
the nitride semiconductor light emitting element further comprises a p-type layer and an n-type layer that are provided on the principal surface side and a rear surface side, respectively, of the light emitting layer;
the plurality of peaks include three or more peaks, and the values of the In composition ratios x at the three or more peaks become smaller or larger in a direction from the p-type layer toward the n-type layer.
8. A nitride semiconductor light emitting element comprising a light emitting layer, wherein:
the light emitting layer includes an In x Ga 1-x N well layer, where 0<x≦1, having a principal surface that is an m-plane;
a depth profile of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks;
values of the In composition ratios x at the respective plurality of peaks are different from one another;
the nitride semiconductor light emitting element further comprises a p-type layer and an n-type layer that are provided on the principal surface side and a rear surface side, respectively, of the light emitting layer;
the plurality of peaks include four or more peaks, and the values of the In composition ratios x at the four or more peaks are arranged so as to be V-shaped or inverted V-shaped in a direction from the p-type layer toward the n-type layer.
9. A nitride semiconductor light emitting element comprising a light emitting layer, wherein:
the light layer includes an In x Ga 1-x N well layer, where 0<x≦1, having a principal surface that is an m-plane;
a depth profile of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks;
values of the In composition ratios x at the respective plurality of peaks are different from one another; and
an absolute value of a temperature coefficient of a wavelength of light generated in the light emitting layer is 0.03 or less.
10. A nitride semiconductor light emitting element comprising a light emitting layer, wherein:
the light emitting layer includes an In x Ga 1-x N well layer 0<x≦1, having a principal surface that is an m-plane;
a depth profile of an In composition ratio x in the In x Ga 1-x N well layer has a plurality of peaks;
values of the In composition ratios x at the respective plurality of peaks are different from one another; and
a temperature coefficient of a wavelength of light generated in the light emitting layer is a negative value.