Type II broadband or polychromatic LEDs

• US 8,148,742 B2
• Filed: 03/29/2010
• Issued: 04/03/2012
• Est. Priority Date: 12/09/2004
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Miller, Thomas J., Haase, Michael A.
• Primary Examiner(s): Louie, Wai Sing
• Application Number:
  US12/748,956
• Publication Number:
  US 20100181581A1
• Time in Patent Office: 736 Days
• Field of Search: 257/94, 257/103
• US Class Current: 257/94
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/28 containing only elements of Group II and Group VI of the Periodic Table

Abstract

An LED is provided comprising two or more light-emitting Type II interfaces wherein at least two of the Type II interfaces differ in transition energy by at least 5%, or more typically by at least 10%, and wherein at least one of the Type II interfaces is within a pn junction. Alternately, an LED is provided comprising two or more light-emitting Type II interfaces wherein at least two of the Type II interfaces differ in transition energy by at least 5%, or more typically by at least 10%. The Type II interfaces may include interfaces from a layer which is an electron quantum well and not a hole quantum well, interfaces to a layer which is a hole quantum well and not an electron quantum well; and interfaces that satisfy both conditions simultaneously. The Type II interfaces may be within a pn or pin junction or not within a pn or pin junction. In the later case, emission from the Type II interfaces may be photopumped by a nearby light source. The LED may be a white or near-white light LED. In addition, graphic display devices and illumination devices comprising the semiconductor device according to the present invention are provided.

Claims

1. An LED comprising two or more Type II interfaces wherein at least two of said two or more Type II interfaces differ in transition energy by at least 5%, wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to yellow, green, blue or violet wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

2. The LED according to claim 1 wherein at least two of said two or more Type II interfaces differ in transition energy by at least 10%.

3. A graphic display device comprising the LED according to claim 1.

4. An illumination device comprising the LED according to claim 1.

5. The LED according to claim 1, wherein at least one of the Type II interfaces comprises a II-VI alloy.