Semiconductor light-emitting element, light source head, and image forming apparatus

• US 9,147,817 B2
• Filed: 09/17/2013
• Issued: 09/29/2015
• Est. Priority Date: 09/17/2013
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Fukunaga, Hideki
• Primary Examiner(s): Amari, Alessandro
• Assistant Examiner(s): KONCZAL, MICHAEL THOMAS
• Application Number:
  US14/028,674
• Publication Number:
  US 20150077497A1
• Time in Patent Office: 742 Days
• Field of Search: 347/120, 347/111, 347/118, 347/127, 347/224, 347/238, 347/243, 347/130, 257/107, 257/84, 257/85, 257/79, 257/437, 257/98, 257/112, 257/102, 438/22, 313/503, 313/504, 313/506
• US Class Current: 1/1
• CPC Class Codes: G03G 15/04054 by LED arrays
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/105 with a resonant cavity structure
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body

Abstract

A semiconductor light-emitting element formed of a semiconductor layer includes a multilayer reflecting mirror, a light-emitting layer, a resonator, and a phase shift layer. The multilayer reflecting mirror is formed on a substrate. The light-emitting layer is formed on the multilayer reflecting mirror. The resonator uses the multilayer reflecting mirror as a lower reflecting mirror and resonates light emitted from the light-emitting layer. The phase shift layer shifts a phase of a resonance spectrum of the resonator to generate a standing wave having plural principal modes.

Claims

1. A semiconductor light-emitting element formed of a semiconductor layer, the semiconductor light-emitting element comprising:

a multilayer reflecting mirror formed on a substrate;

a light-emitting layer formed on the multilayer reflecting mirror;

a resonator that uses the multilayer reflecting mirror as a lower reflecting mirror and that resonates light emitted from the light-emitting layer; and

a phase shift layer that that shifts a phase of a resonance spectrum of the resonator to generate a standing wave having a plurality of principal modes.

2. The semiconductor light-emitting element according to claim 1, further comprising an antireflective layer that prevents reflection of light, the antireflective layer being arranged in an exit region of a light-emitting surface from which light is emitted outside the light-emitting surface.

3. The semiconductor light-emitting element according to claim 2, wherein a refractive index of the antireflective layer is about 1.8 or more and about 2.2 or less.

4. The semiconductor light-emitting element according to claim 3, wherein a length of each of the antireflective layer and the resonator is (0.5*m+0.25)*λ

, where λ

represents a value obtained by dividing a peak wavelength of light emitted outside the light-emitting surface by a refractive index of the semiconductor layer and m represents an integer.

5. The semiconductor light-emitting element according to claim 1, wherein in a case where λ

represents a value obtained by dividing a peak wavelength of light emitted outside the light-emitting surface by a refractive index of the semiconductor layer, the phase shift layer is a semiconductor layer including a combination of a first semiconductor layer having a film thickness of λ

/4, a second semiconductor layer having a film thickness of λ

/2 and having a band gap energy smaller than the first semiconductor layer, and the first semiconductor layer having a film thickness of λ

/4.

6. The semiconductor light-emitting element according to claim 5, wherein the phase shift layer has a plurality of the combinations.

7. The semiconductor light-emitting element according to claim 1, wherein in a case where λ

represents a value obtained by dividing a peak wavelength of light emitted outside the light-emitting surface by a refractive index of the semiconductor layer, the phase shift layer is a multilayer reflecting mirror whose phase is shifted from the multilayer reflecting mirror by λ

/4.

8. The semiconductor light-emitting element according to claim 1, wherein the phase shift layer is arranged between the light-emitting layer and the light-emitting surface or between the light-emitting layer and the multilayer reflecting mirror.

9. The semiconductor light-emitting element according to claim 1, further comprising a phase adjustment layer that adjusts a phase of the resonator, the phase adjustment layer being arranged between the phase shift layer and the light-emitting surface.

10. The semiconductor light-emitting element according to claim 1, further comprising a resonator adjustment layer that adjusts an optical length of the resonator, the resonator adjustment layer being arranged between the phase shift layer and the light-emitting layer.

11. The semiconductor light-emitting element according to claim 1, wherein the semiconductor element is a light-emitting thyristor or a light-emitting diode.

12. A light source head comprising a plurality of the semiconductor light-emitting elements according to claim 1, as light sources.

13. An image forming apparatus comprising:

a photoreceptor;

a charging unit that charges a surface of the photoreceptor;

an exposure unit that includes the light source head according to claim 12, the exposure unit performing exposure, with light emitted from the light source head, in order to form an electrostatic latent image on the surface of the photoreceptor charged by the charging unit;

a developing unit that develops the electrostatic latent image formed by the exposure unit; and

a fixing unit that fixes the electrostatic latent image developed by the developing unit.

14. The semiconductor light-emitting element according to claim 1, wherein the phase shift layer is formed on the multilayer reflecting mirror.

15. The semiconductor light-emitting element according to claim 14, wherein the phase shift layer is formed on the light-emitting layer.

16. The semiconductor light-emitting element according to claim 15, wherein the light-emitting layer is formed between the phase shift layer and the multilayer reflecting mirror.

17. The semiconductor light-emitting element according to claim 1,

wherein the plurality of principal modes include a first principal mode and a second principal mode, and

a spontaneous emission spectrum of the semiconductor light-emitting has a peak between the first principal mode and the second principal mode.

18. The semiconductor light-emitting element according to claim 17,

wherein the plurality of principal modes include a third principal mode between the first principal mode and the second principal mode.

19. The semiconductor light-emitting element according to claim 18,

wherein the third principal mode has a height that is greater than or equal to half a height of the first principal mode and the second principal mode.

20. The semiconductor light-emitting element according to claim 1,

wherein, in a case where a peak of a spontaneous emission spectrum is shifted by a temperature change, a light amount from one of the plurality of principal modes increases and a light amount from another of the plurality of principal modes decreases.