Thiosilicate phosphor compositions and deposition methods using barium-silicon vacuum deposition sources for deposition of thiosilicate phosphor films
The present invention relates to novel thiosilicate phosphor compositions. The invention is further a physical vapor deposition method for the deposition of rare earth activated thiosilicate phosphor compositions comprising providing at least one or more source materials where the source materials may comprise a barium silicon alloy, an intermetallic barium silicon compound, a protected barium metal and combinations thereof; providing an activator species; and effecting deposition of the one or more source materials and activator species as a thin film phosphor composition on a selected substrate. The method allows for the deposition of blue thin film electroluminescent phosphors with high luminance and colors required for TV applications.
1. A physical vapour deposition method for the deposition of a thin film thiosilicate phosphor composition, the method comprising:
providing at least one or more source materials comprising a barium silicon alloy, an intermetallic barium silicon compound, a protected barium metal and combinations thereof;
providing an activator species; and
effecting deposition of said one or more source materials and said activator species in a sulfur vapour atmosphere as a phosphor composition on a selected substrate.
2. The method of claim 1 , wherein said one or more source materials is selected from a sputtering target and an evaporation pellet.
3. The method of claim 1 , wherein said barium silicon alloy is represented as Ba x Si where 0.5<x<2.2.
4. The method of claim 3 , wherein 1.8<x<2.2.
5. The method of claim 1 , wherein said intermetallic barium silicon compound is BaSi.
6. The method of claim 1 , wherein said intermetallic barium silicon compound is BaSi 2 .
7. The method of claim 1 , wherein said source material is a protected barium metal and an additional source material is used in the method and is selected from the group consisting of elemental silicon, a silicon sulfide compound and a source of elemental sulfur.
8. The method of claim 1 , wherein said protected barium metal comprises barium metal covered with a volatile passivating film.
9. The method of claim 8 , wherein said volatile passivating film is a layer of a non-protic solvent.
10. The method of claim 8 , wherein said volatile passivating film is a layer of barium oxide, barium sulfate or inert barium compound.
11. The method of claim 1 , wherein said one or more source materials further comprises elemental silicon or silicon sulfide.
12. The method of claim 1 , wherein said one or more source materials comprises a protected barium metal as a first source and elemental silicon or silicon sulfide as a second source.
13. The method of claim 1 , wherein said sulfur vapour atmosphere is H 2 S.
14. The method of claim 13 , wherein said sulfur vapour atmosphere is generated remotely from said source materials.
15. The method of claim 14 , wherein said sulfur vapour atmosphere is generated from a polysulfide compound.
16. The method of claim 1 , wherein said deposition is effected by a method selected from sputtering, thermal evaporation and electron beam evaporation.
17. The method of claim 16 , wherein said method is sputtering.
18. The method of claim 16 , wherein said method is selected from the group consisting of electron beam evaporation and thermal evaporation.
19. The method of claim 1 , wherein said activator species is selected from europium and cerium.
20. The method of claim 19 , wherein said activator species is cerium.
21. The method of claim 19 , wherein said activator species is incorporated within said one or more source materials.
22. The method of claim 19 , wherein said activator species is provided separate from said one or more source materials.
23. The method of claim 3 , wherein said method comprises a single source material of a barium silicon alloy, said activator species is provided doped within said compound and a sulfur source is incorporated within said compound.
24. The method of claim 5 , wherein said method comprises a single source material comprising an intermetallic barium silicon compound, an activator species and sulfur.
25. A physical vapour deposition method for the deposition of a thin film thiosilicate phosphor composition, the method comprising:
providing at least one or more source materials comprising a barium-silicon alloy, an intermetallic barium silicon compound, a protected barium metal and combinations thereof;
providing an activator species to said one or more source materials or separately; and
effecting deposition in a sulfur vapour atmosphere of said source materials and said activator species as a phosphor composition on a selected substrate.
26. The method of claim 25 , wherein said intermetallic barium silicon compound is BaSi.
27. The method of claim 25 , wherein intermetallic barium silicon compound is BaSi 2 .
28. The method of claim 25 , wherein said barium silicon alloy is represented as Ba x Si where 0.5<x<2.2.
29. The method of claim 28 , wherein 1.8<x<2.2.
30. The method of claim 25 , wherein said source material is a protected barium metal and an additional source material is used in the method and is selected from the group consisting of elemental silicon, a silicon sulfide compound and a source of elemental sulfur.
31. The method of claim 25 , wherein said protected barium metal comprises barium metal covered with a volatile passivating film.
32. The method of claim 31 , wherein said volatile passivating film is a layer of a non-protic solvent.
33. The method of claim 25 , wherein said one or more source materials further comprises elemental silicon or a silicon suifide compound.
34. The method of claim 25 , wherein said phosphor composition represented as Ba 2 SiS 54 RE where RE is a rare earth element selected from europium and cerium.
35. The method of claim 25 , wherein said sulfur vapour atmosphere is H 2 S.
36. The method of claim 35 , wherein said sulfur vapour atmosphere is generated remotely from said source materials.
37. The method of claim 35 , wherein said sulfur vapour atmosphere is generated from a polysulfide compound.
38. The method of claim 25 , wherein said deposition is effected by a method selected from sputtering, thermal evaporation and electron beam evaporation.
39. The method of claim 25 , wherein said activator species is selected from europium and cerium.
40. The method of claim 39 , wherein said activator species is cerium.
41. The method of claim 39 , wherein said activator species is incorporated within said one or more source materials.
42. The method of claim 39 , wherein said activator species is provided separate from said one or more source materials.
43. A physical vapour deposition method for the deposition of a barium thiosilicate phosphor composition, the method comprising:
providing a source material comprising Ba x Si where 0.5<x<2.2 and an activator species; and
effecting deposition of said source material and said activator species as a phosphor composition on a selected substrate in a sulfur vapour atmosphere.
44. The method of claim 43 , wherein said sulfur vapour atmosphere is H 2 S.
45. The method of claim 11 , wherein said sulfur vapour atmosphere is H 2 S.
46. The method of claim 4 , wherein said method comprises a single source material of a barium silicon alloy, said activator species is provided doped within said compound and a sulfur source is incorporated within said compound.
47. The method of claim 6 , wherein said method comprises a single source material comprising an intermetallic barium silicon compound, an activator species and sulfur.