Graded electron blocking layer
First Claim
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1. A light emitting device, comprising:
- a p-side heterostructure;
an n-side heterostructure;
an active region disposed between the p-side heterostructure and the n-side heterostructure and configured to emit light;
an electron blocking layer (EBL) disposed on a growth surface and arranged between the p-side heterostructure and the active region, the EBL having a thickness and comprising an aluminum containing group-III-nitride alloy; and
a p-side superlattice disposed on the electron blocking layer,wherein an aluminum composition of the EBL changes as a function of distance along a growth direction-from the active region towards the p-side heterostructure over a majority of the thickness of the EBL, and wherein the change in the aluminum composition is dependent on growth surface orientation, wherein the aluminum composition in the EBL decreases along the growth direction for a growth surface orientation having crystallographic indices (hk( h+k)m) with m greater than zero or the aluminum composition in the EBL increases along the growth direction for a growth surface orientation having crystallographic indices (hk( h+k)m) with m less than zero.
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Abstract
A light emitting device includes a p-side heterostructure, an n-side heterostructure, an active region disposed between the p-side heterostructure and the n-side heterostructure. An electron blocking layer (EBL) disposed between the p-side heterostructure and the active region comprises an aluminum containing group-III-nitride alloy. An aluminum composition of the EBL decreases as a function of distance along a [0001] direction from the active region towards the p-side heterostructure over a majority of the thickness of the EBL.
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Citations
29 Claims
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1. A light emitting device, comprising:
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a p-side heterostructure; an n-side heterostructure; an active region disposed between the p-side heterostructure and the n-side heterostructure and configured to emit light; an electron blocking layer (EBL) disposed on a growth surface and arranged between the p-side heterostructure and the active region, the EBL having a thickness and comprising an aluminum containing group-III-nitride alloy; and a p-side superlattice disposed on the electron blocking layer, wherein an aluminum composition of the EBL changes as a function of distance along a growth direction-from the active region towards the p-side heterostructure over a majority of the thickness of the EBL, and wherein the change in the aluminum composition is dependent on growth surface orientation, wherein the aluminum composition in the EBL decreases along the growth direction for a growth surface orientation having crystallographic indices (hk( h+k )m) with m greater than zero or the aluminum composition in the EBL increases along the growth direction for a growth surface orientation having crystallographic indices (hk(h+k )m) with m less than zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A light emitting device, comprising:
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a p-side heterostructure; an n-side heterostructure; an active region disposed between the p-side heterostructure and the n-side heterostructure and configured to emit light; and an electron blocking layer (EBL) disposed between the p-side heterostructure and the active region and having a thickness, the EBL comprising AlyGa1-yN, wherein y is graded in a number of discrete steps, a width of the steps changing as a function of distance along a growth direction from the active region towards the p-side heterostructure over a majority of the thickness of the EBL, wherein an aluminum composition of the EBL changes as a function of distance along the growth direction-from the active region towards the p-side heterostructure over a majority of the thickness of the EBL, wherein the change in the aluminum composition is dependent on growth surface orientation, wherein the aluminum composition in the EBL decreases along the growth direction for a growth surface orientation having crystallographic indices (hk( h+k )m) with m greater than zero or the aluminum composition in the EBL increases along the growth direction for a growth surface orientation having crystallographic indices (hk(h+k )m) with m less than zero. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A light emitting device, comprising:
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a p-side heterostructure; an n-side heterostructure; an active region disposed between the p-side heterostructure and the n-side heterostructure and configured to emit light, the active region comprising a III-nitride material; and an electron blocking layer (EBL) disposed on a growth surface and arranged between the p-side heterostructure and the active region, the EBL having a thickness and comprising an aluminum containing group III-nitride alloy, wherein a change in an aluminum composition of the EBL is dependent on orientation of a growth surface, and wherein the growth surface orientation is a semi-polar growth surface orientation identified by crystallographic indices (hk( h+k )m) with m>
0 and the aluminum composition in the EBL decreases as a function of distance along a growth direction normal to the growth surface over a majority of a thickness of the EBL, orthe growth surface orientation is a semi-polar growth surface orientation identified by crystallographic indices (hk( h+k )m) with m<
0 and the aluminum composition increases as a function of distance along the growth direction normal to the growth surface over a majority of a thickness of the EBL. - View Dependent Claims (18, 19, 20)
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21. A light emitting device, comprising:
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a p-side heterostructure; an n-side heterostructure; an active region disposed between the p-side heterostructure and the n-side heterostructure and configured to emit light, the active region comprising a number of quantum wells separated by barriers, the barriers including a last barrier comprising AlzGa1-zN, only a portion of the last barrier being doped with a p-type dopant; and an electron blocking layer (EBL) disposed on a growth surface and arranged between the p-side heterostructure and the last barrier, the EBL comprising AlyGa1-yN, wherein y changes as a function of distance from the last barrier and the change in y is dependent on orientation of the growth surface, wherein y decreases as a function of distance along a growth direction over a majority of a thickness of the EBL for a growth surface orientation identified by crystallographic indices (hk( h+k )m) with m>
0 or y increases as a function of distance along the growth direction over a majority of the thickness of the EBL for a growth surface orientation identified by crystallographic indices (hk(h+k )m) with m<
0, andwherein a value of z proximate the EBL is greater than the value of z proximate the quantum well. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A method of making a light emitting device, comprising:
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growing an n-side heterostructure on a polar or semipolar face of a substrate; growing an active region comprising one or more quantum wells disposed between barriers, the active region configured to emit light during operation of the light emitting device; growing a p-side heterostructure; and growing an electron blocking layer on the active region, wherein the electron blocking layer (EBL) is grown on a growth surface and is disposed between the p-side heterostructure and the active region, the EBL having a thickness and comprising an aluminum containing group III-nitride alloy, wherein; growing the EBL comprises grading an aluminum composition of the EBL dependent on orientation of the growth surface such that the growth surface orientation has crystallographic indices (hk( h+k )m) with m>
0 and the aluminum composition in the EBL decreases as a function of distance over a majority of the thickness of the EBL along a growth direction normal to the growth surface or the growth surface orientation has crystallographic indices (hk(h+k)m) with m<
0 and the aluminum composition in the EBL increases as a function of distance over a majority of the thickness of the EBL along the growth direction normal to the growth surface. - View Dependent Claims (29)
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Specification