Multiple quantum well light emitting device with multi-layer barrier structure

Patent metadata

Field	Value
Publication number	US-9711682-B2
Application number	US-201313969811-A
Country	US
Kind code	B2
Filing date	Aug 19, 2013
Priority date	Aug 23, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

The light emitting device includes a first conductive semiconductor layer; a second conductive semiconductor layer on the first conductive semiconductor layer; and an active layer between the first and second conductive semiconductor layers. The active layer includes a plurality of well layers and a plurality of barrier layers, wherein the well layers include a first well layer and a second well layer adjacent to the first well layer. The barrier layers include a first barrier layer disposed between the first and second well layers, and the first barrier layer includes a plurality of semiconductor layers having an energy bandgap wider than an energy bandgap of the first well layer. At least two layers of the plurality of semiconductor layers are adjacent to the first and second well layers, and have aluminum contents greater than that of the other layer.

First claim

What is claimed is:

1. A light emitting device comprising:
a first conductive semiconductor layer;
a second conductive semiconductor layer on the first conductive semiconductor layer; and
an active layer between the first and second conductive semiconductor layers, the active layer including a plurality of well layers and a plurality of barrier layers,
wherein the plurality of well layers has a first well layer and a second well layer adjacent to the first well layer,
wherein the plurality of barrier layers has a first barrier layer disposed between the first and second well layers,
wherein the first barrier layer has a plurality of semiconductor layers having an energy bandgap wider than an energy bandgap of the first well layer,
wherein at least two layers of the plurality of semiconductor layers which are adjacent to the first and second well layers have aluminum contents greater than that of another layer of the plurality of semiconductor layers,
wherein the other layer of the plurality of semiconductor layers is formed of a ternary or quaternary compound semiconductor including aluminum (Al) and nitrogen (N),
wherein the at least two layers of the plurality of semiconductor layers are formed of a binary compound semiconductor including aluminum (Al),
wherein the active layer emits light having a wavelength of 385 nm or less,
wherein the first and second well layers are formed of a gallium nitrogen (GaN) layer, and
wherein a thickness of each of the at least two layers of the plurality of semiconductor layers is thinner than a thickness of each of the first and second well layers.

2. The light emitting device of claim 1 , wherein the thickness of each of the at least two layers of the plurality of semiconductor layers is thinner than that of the other layer of the plurality of semiconductor layers and wherein the thickness of each of the at least two layers of the plurality of semiconductor layers is in a range of 1 nm to 4 nm.

3. The light emitting device of claim 1 , wherein the at least two layers of the plurality of semiconductor layers have energy bandgaps wider than that of the other of the plurality of semiconductor layers, and
wherein the at least two layers of the plurality of semiconductor layers contact the other layer.

4. The light emitting device of claim 3 , wherein the at least two layers of the plurality of semiconductor layers have a barrier height higher than that of the other layer of the plurality of semiconductor layers,
wherein the at least two layers of the plurality of semiconductor layers are formed of an AlN layer, and
wherein the other layer of the plurality of semiconductor layers is formed of an AlGaN layer.

5. The light emitting device of claim 1 , wherein the at least two layers of the plurality of semiconductor layers have a lattice constants smaller than that of the other of the plurality of semiconductor layers,
wherein the at least two layers of the plurality of semiconductor layers are formed of an AlN layer, and
wherein the other layer of the plurality of semiconductor layers is formed of an AlGaN layer.

6. The light emitting device of claim 1 , wherein the plurality of semiconductor layers comprise:
a first semiconductor layer having a second energy bandgap wider than a first energy bandgap of the first well layer;
a second semiconductor layer between the first well layer and the first semiconductor layer, the second semiconductor layer having a third energy bandgap wider than the second energy bandgap; and
a third semiconductor layer between the first semiconductor layer and the second well layer, the third semiconductor layer having a fourth energy bandgap wider than the second energy bandgap,
wherein the second and third semiconductor layers are formed of an AlN layer, and
wherein the first semiconductor layer is formed of an AlGaN layer,
wherein the second semiconductor layer contacts the first well layer and the third semiconductor layer contact the second well layer, and
wherein the first semiconductor layer contacts the second and third semiconductor layers.

7. The light emitting device of claim 6 , wherein each of the second and third semiconductor layers has a thickness thinner than a thickness of the first well layer, and
wherein the thickness of each of the second and third semiconductor layers is in a range of 1 nm to 4 nm.

8. The light emitting device of claim 7 , wherein a difference of a thickness of the first semiconductor layer and the thickness of the first well layer is less than a difference of the thickness of the second semiconductor layer and the thickness of the first semiconductor layer.

9. The light emitting device of claim 7 , wherein the second and third semiconductor layers includes a material having a lattice constant less than a lattice constant of the first semiconductor layer, and the aluminum content of the first semiconductor layer is in the range of 5% to 10%.

10. The light emitting device of claim 7 , wherein the thickness of the second semiconductor layer is equal to the thickness of the third semiconductor layer.

11. The light emitting device of claim 1 , wherein the first conductive semiconductor layer includes AlGaN and the second conductive semiconductor layer includes AlGaN, and wherein the active layer emits a UV light having a peak wavelength of 285 nm to 385 nm.

12. The light emitting device of claim 1 , wherein at least one of the plurality of semiconductor layers has a first region and a second region, the first region having an Al composition ratio less than an Al composition ratio of the second region, wherein the first well layer is closer to the first conductive semiconductor layer than to the second well layer, and wherein the first region is closer to the first well layer than to the second region.

13. A light emitting device comprising:
a first conductive semiconductor layer including an n type dopant;
a second conductive semiconductor layer on the first conductive semiconductor layer, the second conductive semiconductor layer including a p type dopant;
an active layer between the first and second conductive semiconductor layers, the active layer including a plurality of well layers and a plurality of barrier layers; and
an electron blocking layer between the active layer and the second conductive semiconductor layer,
wherein the plurality of well layers comprise a first well layer and a second well layer adjacent to the first well layer,
wherein the plurality of barrier layers comprise a first barrier layer disposed between the first and second well layers,
wherein the first barrier layer comprises a plurality of semiconductor layers having an energy bandgap wider than an energy bandgap of the first well layer,
wherein at least two layers of the plurality of semiconductor layers which are adjacent to the first and second well layers have lattice constants smaller than that of another layer of the plurality of semiconductor layers, and
wherein the at least two layers of the plurality of semiconductor layers have aluminum contents greater than that of the other layer of the plurality of semiconductor layers,
wherein the other layer of the plurality of semiconductor layers is formed of a ternary or quaternary compound semiconductor including aluminum (Al) and nitrogen (N),
wherein the at least two layers of the plurality of semiconductor layers are formed of a binary compound semiconductor including aluminum (Al) and contact the other layer, and
wherein the active layer emits light having a wavelength of 385 nm or less,
wherein the first well layer is closer to the first conductive semiconductor layer than to the se

Assignees

• Lg Innotek Co Ltd

Inventors

• Han Young Hun
• Choi Rak Jun
• Oh Jeong Tak

Classifications

• H01L33/12 Primary

  Electricity · mapped topic

• H01L33/32

  Electricity · mapped topic

• H01L2224/48091

  Electricity · mapped topic

• H01L2924/00014

  Electricity · mapped topic

• H01L33/06

  Electricity · mapped topic