Phosphors for use with LEDs and other optoelectronic devices

• US 9,035,344 B2
• Filed: 09/11/2012
• Issued: 05/19/2015
• Est. Priority Date: 09/14/2011
• Status: Active Grant

• Current Assignee: VerLASE Technologies, LLC
• Original Assignee: VerLASE Technologies, LLC
• Inventors: Jain, Ajaykumar R.
• Primary Examiner(s): AHMED, SELIM U
• Application Number:
  US14/241,564
• Publication Number:
  US 20140367719A1
• Time in Patent Office: 980 Days
• Field of Search: 257/13, 257/78, 257/88, 257/98, 257/99, 257/E27.12, 257/E33.06
• US Class Current: 257/98
• CPC Class Codes: C09K 11/88 containing selenium, tellurium or unspecified chalcogen elements
• 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 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

Phosphors fabricated from one or more layers of a naturally lamellar or fabricated lamellar semiconductor that is combined with a substrate. One or more of the layers of the lamellar semiconductor are separated from bulk material. The one or more layers are transformed into a phosphor for use with one or more light-emitting devices for the purpose of modifying the light emitted by the light-emitting device(s). Such transformation can be effected in a variety of ways, such as precise thinning or thickening of the removed layer(s) and/or intercalating one or more species of ions into the layer(s) that function as phosphors.

Claims

1. A phosphor for use with an optoelectronic device, said phosphor comprising:

one or more lamellae separated from a bulk material, said bulk material being a lamellar semiconductor having at least one van der Waals cleavage plane and being configured to be cleavable along said at least one van der Waals cleavage plane into a plurality of said one or more lamellae, and wherein said one or more lamellae are tuned to the optoelectronic device so as to provide a photoluminescence output.

2. A phosphor according to claim 1, wherein said lamellar semiconductor is GaSe.

3. A phosphor according to claim 1, wherein said lamellar semiconductor includes a cleavage fracture plane at a desired thickness, said desired thickness corresponding to the thickness of one of said lamellar semiconductor lamellae.

4. A phosphor according to claim 1, wherein each of said one or more lamellae is less than about 100 nm in thickness.

5. A phosphor according to claim 1, wherein between each pair of said one or more lamellae is a separator layer.

6. A phosphor according to claim 5, wherein said separator layer comprises a semiconductor separator layer.

7. A phosphor according to claim 5, wherein said separator layer comprises an insulator separator layer.

8. A phosphor according to claim 1, wherein said bulk material includes an intercalated guest species between at least one pair of said one or more lamellae.

9. A phosphor according to claim 8, wherein said intercalated guest species is a rare earth metal for providing photoluminescence.

10. A phosphor according to claim 1, wherein said one or more lamellae has a non-uniform thickness such that the conversion of an input wavelength by the phosphor results in a multiple differing output wavelengths.

11. A phosphor according to claim 1, wherein the photoluminescence output of said one or more lamellae is based upon an input from the optoelectronic device.

12. A phosphor according to claim 11, wherein the optoelectronic device is a light emitting diode.

13. A phosphor according to claim 11, wherein the optoelectronic device is a laser diode.

14. A phosphor according to claim 11, wherein the optoelectronic device is a vertical cavity surface emitting laser.

15. A phosphor according to claim 11, wherein the optoelectronic device is a vertical external cavity surface emitting laser.

16. A phosphor according to claim 1, wherein the optoelectronic device is a photovoltaic cell.

17. A phosphor according to claim 1, wherein the photoluminescence output of said one or more lamellae has a center wavelength of emission of about 600 nm to about 620 nm and a bandwidth of about 30 nm.

18. A phosphor according to claim 1, wherein the photoluminescence output of said one or more lamellae has a center wavelength of emission of about 610 nm to about 615 nm and a bandwidth of about 30 nm to about 40 nm.

19. A phosphor according to claim 1, wherein the photoluminescence output is in the visible part of the electromagnetic spectrum.

20. A phosphor according to claim 19, wherein the photoluminescence output has a center wavelength of emission of about 600 nm to about 625 nm and a bandwidth of about 30nm to about 40 nm.

21. A phosphor according to claim 1, wherein the photoluminescence output is in the ultraviolet part of the electromagnetic spectrum.

22. A phosphor according to claim 1, wherein the photoluminescence output is in the near infrared part of the electromagnetic spectrum.

23. A method of producing a phosphor for modifying an electromagnetic input, the method comprising:

providing a bulk lamellar semiconductor having at least one van der Waals cleavage plane and a first surface;

bonding a permanent substrate to the first surface of the bulk lamellar semiconductor;

inducing a cleavage in the bulk lamellar semiconductor so as to generate a first cleaved semiconductor portion and a second cleaved semiconductor portion; and

detaching the permanent substrate and the first cleaved semiconductor portion from the second cleaved semiconductor portion, wherein the first cleaved semiconductor portion is a lamellae of the phosphor and wherein the lamellae is designed and configured to modify the electromagnetic input.

24. A method according to claim 23, wherein said providing a bulk lamellar semiconductor includes providing bulk lamellar GaSe.

25. A method according to claim 23, wherein said inducing a cleavage includes the steps of:

intercalating a guest species between the lamellae of the bulk lamellar semiconductor; and

providing an impulse to separate one or more of the lamellae of the bulk layered semiconductor.

26. A method according to claim 25, wherein said intercalating a guest species includes intercalating a rare earth metal for providing the photoluminescence.

27. A method according to claim 23, further including providing a separating layer on top of the first cleaved semiconductor portion.

28. A method according to claim 27, wherein said providing a separating layer includes depositing a semiconducting layer.

29. A method according to claim 27, wherein said providing a separating layer includes depositing an electrically insulating layer.

30. A method according to claim 23, further including modifying the first cleaved semiconducting portion so as to have a non-uniform thickness.

31. A method of fabricating a phosphor, comprising:

providing a lamellar semiconductor having at least one van der Waals cleavage plane and at least one detachable lamella;

separating the detachable lamella; and

including the detachable lamella with an optoelectronic device as an optical functional element of the optoelectronic device.

32. A method according to claim 31, wherein said providing the lamellar semiconductor includes providing an inherently lamellar material and said separating includes liberating at least one lamella from the inherently lamellar semiconductor.

33. A method according to claim 32, wherein said providing an inherently lamellar material includes providing a material comprising gallium and selenium.

34. A method according to claim 32, wherein said inherently lamellar material includes a lamellar material having a bulk band gap greater than or equal to 0.4 eV and less than or equal to 1.8 eV.

35. A method according to claim 32, wherein said inherently lamellar material includes a lamellar material having a bulk band gap greater than or equal to 1.8 eV and less than or equal to 2.5 eV.

36. A method according to claim 32, wherein said inherently lamellar material includes a lamellar material having a band gap greater than or equal to 2.5 eV and less than or equal to 4.5 eV.

37. A method according to claim 31, wherein said providing the lamellar semiconductor includes providing a lamellar semiconductor having at least one fabricated lamella.

38. A method according to claim 37, wherein said providing the lamellar semiconductor having at least one fabricated lamella includes providing a lamellar semiconductor having a deposited lamella deposited on a substrate, and said separating includes detaching the deposited lamella from the substrate.

39. A method according to claim 37, wherein said providing the lamellar semiconductor having at least one fabricated lamella includes providing a lamellar semiconductor having a plurality of fabricated lamellae defined by planes of weakness resulting from intercalation.

40. A method according to claim 37, wherein said providing the lamellar semiconductor having at least one fabricated lamella includes providing a lamellar semiconductor having a plurality of semiconductor-paper lamellae.

41. A method according to claim 31, wherein the detachable layer has a thickness and the method further comprises tuning the thickness of the detachable lamella as a function of desired characteristics of the phosphor.

42. A method according to claim 41, wherein said tuning the thickness is performed in conjunction with said separating.

43. A method according to claim 31, wherein said separating the detachable lamellae results in a quantum confinement lamella.

44. A method according to claim 31, wherein said providing the lamellar semiconductor includes providing a crystalline semiconductor having a plurality of lamellae, and said separating the detachable lamella from the lamellar semiconductor includes separating a subset of the plurality of lamellae from the crystalline semiconductor.

45. A method according to claim 44, wherein said separating the subset of the plurality of lamellae includes separating multiple lamellae from the crystalline semiconductor.

46. A method according to claim 31, further comprising sandwiching the detachable lamella between two semiconductor layers, wherein each of the two semiconductor layers has a band gap greater than the band gap of the detachable lamella.

47. A method according to claim 46, further comprising providing the detachable lamella with a thickness less than approximately 100 nm so that the detachable lamella functions as a quantum confinement lamella within the phosphor.

48. A method according to claim 46, further comprising providing the detachable lamella with a non-uniform thickness, thereby causing the optoelectronic device to emit a plurality of output wavelengths when subjected to an appropriate optical impulse.

49. A method according to claim 48, wherein said non-uniform thickness is curvilinear.

50. A method according to claim 48, wherein said non-uniform thickness is planar.

51. A method according to claim 31, further comprising modifying the band gap of the detachable lamella using an intercalant.

52. A method according to claim 31, further comprising modifying the band gap of the detachable lamella by exfoliation.

53. A method according to claim 31, wherein said separating is accomplished using an intercalant.

54. A method of fabricating an optoelectronic device including a phosphor as an optically functional element, the method comprising:

providing a lamellar semiconductor having at least one van der Waals cleavage plane and a crystalline semiconductor lamella, wherein the lamellar semiconductor is configured to allow the crystalline semiconductor lamella to be separated therefrom;

separating the crystalline semiconductor lamella from the lamellar semiconductor;

including the crystalline semiconductor lamella with the optoelectronic device as the phosphor; and

providing the optically functional element with a predetermined thickness based on the optical function of the optoelectrically functional element.

55. A method according to claim 54, wherein:

said providing the lamellar semiconductor includes depositing the crystalline semiconductor lamella onto a reusable crystalline substrate; and

said separating includes separating the crystalline semiconductor lamella from said crystalline substrate.

56. A method according to claim 54, wherein:

said providing the lamellar semiconductor includes providing a lamellar semiconductor comprising a plurality of crystalline semiconductor lamellae; and

said separating includes separating a subset of said plurality of crystalline semiconductor lamellae.

57. A method according to claim 54, wherein said providing the lamellar semiconductor includes fabricating the lamellar semiconductor to include a plurality of crystalline semiconductor lamellae.

58. A method according to claim 57, wherein said fabricating includes assembling a plurality of crystalline paper lamellae.

59. A method according to claim 57, wherein said fabricating includes intercalating a precursor to the lamellar semiconductor so as to create planes of weakness that define a plurality of crystalline semiconducting lamellae.

60. A method according to claim 54, wherein said providing the at least one optically functional element with a predetermined thickness is performed as part of said separating.

61. A method according to claim 54, wherein said providing the at least one optically functional element with a predetermined thickness includes, after said separating, adjusting the thickness of the crystalline semiconductor lamella.

62. A method according to claim 61, wherein said adjusting the thickness includes removing material from the crystalline semiconductor lamella.

63. A method according to claim 61, wherein said adjusting the thickness includes adding material on the crystalline semiconductor lamella.

64. A phosphor for use with an optoelectronic device, said phosphor comprising:

a layered substrate, wherein at least a portion of the layered substrate has been separated from a lamellar semiconductor having at least one van der Waals cleavage plane, the layered substrate including one or more of an insulator, a semiconductor, and a conductor;

a layer of wide band gap II-VI materials disposed on said layered substrate, wherein said layer of wide band gap II-VI materials is designed and configured as a function of the optoelectronic device to photoluminesce when subjected to an electromagnetic input.

65. A phosphor for use with an optoelectronic device, said phosphor comprising:

a layered substrate, wherein at least a portion of the layered substrate has been separated from a lamellar semiconductor having at least one van der Waals cleavage plane, the layered substrate including one or more of an insulator, a semiconductor, and a conductor;

a barrier layer disposed on said layered substrate; and

a quantum confining layer disposed on said barrier layer, wherein said layered substrate, barrier layer, and quantum confining layer are designed and configured as a function of the optoelectronic device to photoluminesce when subjected to an electromagnetic input.

66. A phosphor for use with an optoelectronic device, said phosphor comprising:

a permanent substrate; and

a lamellar layer separated from a lamellar semiconductor having at least one van der Waals cleavage plane, the lamellar layer including one or more of an insulator, a semiconductor, and a conductor disposed on said permanent substrate, wherein said lamellar layer is intercalated with one or more rare earth elements and wherein said lamellar layer and said one or more rare earth elements is tuned relative to the optoelectronic device so as to photoluminesce when subjected to an electromagnetic input.