GROUP III NITRIDE WHITE LIGHT EMITTING DIODE

• US 20090206320A1
• Filed: 03/24/2005
• Published: 08/20/2009
• Est. Priority Date: 03/24/2005
• Status: Abandoned Application

• Current Assignee: Agency For Science Technology and Research (Government of Singapore), Sumitomo Electric Industries, Inc.
• Original Assignee: Agency For Science Technology and Research (Government of Singapore)
• Inventors: Takasuka, Eiryo, Chua, Soo Jin, Chen, Peng
• Application Number:
  US11/909,613
• Publication Number:
  US 20090206320A1
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A white light-emitting diode is fabricated by metal organic chemical vapor deposition (MOCVD), which can produce a broad band emission covering all the visible range in the spectrum by capping the Indium nitride (InN) and Indium-rich Indium Gallium Nitride (InGaN) quantum dots (QDs) in single or multiple In_xGa_1-xN/In_yGa_1-yN quantum wells (QWs) by introducing bursts of at least one of Timethylindium (TMIn), Triethylindium (TEIn) and Ethyldimethylindium (EDMIn), which serve as nuclei for the growth of QDs in QWs. The diode can thus radiate white light ranging from 400 nm to 750 nm by adjusting the In burst parameters.

Claims

1. A diode for emitting white-light, the diode comprising:

a substrate;

a buffer layer formed over the substrate, the buffer layer being divided into a first section and a second section; and

at lease one quantum well structure comprising a modified In_xGa_1-xN/In_yGa_1-yN quantum well/barrier bilayer that encompasses InN and indium-rich InGaN quantum dots, formed over the first section of the buffer layer, wherein the modified quantum well structure exhibits a photoluminescence spectrum simultaneously covering the primary colours of blue, green and red.

2. The diode of claim 1, wherein the quantum dots are formed by first flowing at least one of TMIn, TEIn or EDMIn at a first flow rate and a first time to form nuclei, and then flowing at least one of TMIn, TEIn or EDMIn with TMG and ammonia at a second flow rate to make the nuclei grow and be capped in the quantum wells.

3. The diode of claim 1, wherein there are between about 1 to 30 of the quantum well structures.

4. The diode of claim 1, wherein a thickness of the IN_xGa_1-xN quantum well layer is about 1 to 10 nm and a thickness of the IN_yGa_1-yN quantum barrier layer is about 5 to 30 nm.

5. The diode of claim 1, wherein 1>

x>

y>

0 or y=0.

6. The diode of claim 1, wherein the substrate is sapphire, SiC or ZnO.

7. The diode of claim 1, wherein at least one of biscyclopentadienyl magnesium, diethyl zinc or saline are used as dopants.

8. The diode of claim 1, wherein the photoluminescence spectrum covers a wavelength range of about 400 nm to 750 nm.

9. A modified quantum well structure that emits white light, which comprises:

an In_xGa_1-xN quantum well layer;

InN and indium-rich InGaN quantum dots embedded in the In_xGa_1-xN quantum well layer; and

an In_yGa_1-yN quantum barrier layer over the quantum dots and the quantum well layer, wherein the modified quantum well structure exhibits a photoluminescence spectrum simultaneously covering the primary colours of blue, green and red.

10. The quantum well structure of claim 9, wherein the quantum dots are formed by first flowing at least one of TMIn, TEIn or EDMIn at a first flow rate and a first time to form nuclei, and then flowing at least one of TMIn, TEIn or EDMIn with TMG and ammonia at a second flow rate to make the nuclei grow and be capped in the quantum wells.

11. The quantum well structure of claim 9, wherein a thickness of the In_xGa_1-xN quantum well layer is about 1 to 10 nm and a thickness of the In_yGa_1-yN quantum barrier layer is about 5 to 30 nm.

12. The quantum well structure of claim 9, wherein 1>

x>

y>

0 or y=0.

13. A process for forming a diode for emitting white light, the process comprising the steps of:

providing a substrate;

forming a buffer layer formed over the substrate, the buffer layer being divided into a first section and a second section; and

forming at least one quantum well structure comprising a modified In_xGa_1-xN/In_yGa_1-yN quantum well/barrier bilayer that encompasses InN and indium-rich InGaN quantum dots, formed over the first section of the buffer layer, the modified quantum well structure exhibiting a photoluminescence spectrum simultaneously covering the primary colours of blue, green and red.

14. The process of claim 13, wherein the quantum dots are formed by the steps of:

flowing at least one of TMIn, TEIn or EDMIn at a first flow rate and a first time to form nuclei; and

flowing at least one of TMIn, TEIn or EDMIn with TMG and ammonia at a second flow rate to make the nuclei grow and be capped in the quantum wells.

15. The process of claim 14, wherein different flow rates of TMIn, TEIn or EDMIn produce quantum wells of different sizes.

16. The diode of claim 13, wherein there are between about 1 to 30 of the quantum well structures.

17. The diode of claim 13, wherein a thickness of the In_xGa_1-xN quantum well layer is about 1 to 10 nm and a thickness of the In_yGa_1-yN quantum barrier layer is about 5 to 30 nm.

18. The diode of claim 13, wherein 1>

x>

y>

0 or y=0.

19. The diode of claim 13, wherein the substrate is sapphire, SiC or ZnO.

20. The diode of claim 13, wherein at least one biscyclopentadienyl magnesium, diethyl zinc or silane are used as dopants