Reactive metal sources and deposition method for thioaluminate phosphors
A physical vapor deposition method for the deposition of thioaluminate phosphor compositions includes providing one or more source materials including an intermetallic barium aluminum compound, a barium aluminum alloy or a protected barium metal, providing an activator species and effecting deposition of the one or more source materials and activator species as a 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 thioaluminate phosphor compositions, the method comprising:
providing one or more source materials selected from the group consisting of an intermetallic barium aluminum compound, a barium aluminum alloy and a protected barium metal;
providing an activator species;
effecting physical vapour deposition of one or more source materials and said activator species in a sulfur vapour atmosphere as a thioaluminate phosphor composition on a selected substrate; and
wherein the protected barium metal is a composite of a barium aluminum alloy and an aluminum metal or a barium metal covered with a volatile passivating film.
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 one or more source materials is an intermetallic barium aluminum compound is selected from the group consisting of BaAl 4 , Ba 7 Al 13 and Ba 4 Al 5 .
4. The method of claim 3 , wherein said intermetallic barium aluminum compound is BaAl 4 .
5. The method of claim 1 , wherein said one or more source materials is a barium aluminum alloy of the formula Ba x Al where x is in the range of about 0.15 to about 0.45.
6. The method of claim 5 , wherein x is in the range of about 0.20 to about 0.35.
7. The method of claim 1 , wherein said one or more source materials is a protected barium metal comprising a composite of a barium aluminum alloy and aluminum metal.
8. The method of claim 1 , wherein said one or more source materials is a protected barium metal comprising 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 aluminum metal or aluminum sulfide.
12. The method of claim 1 , wherein said phosphor composition is a barium thioaluminate.
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 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 europium.
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 an intermetallic compound of BaAl 4 , said activator species is provided doped within said compound and a sulfur source is incorporated within said compound.
24. The method of claim 3 , wherein said method comprises a single source material comprising an intermetallic compound of BaAl 4 , an activator species and sulfur.
25. A physical vapour deposition method for the deposition of thioaluminate phosphor compositions, the method comprising:
providing one or more source materials selected from the group consisting of an intermetallic barium aluminate compound, a barium aluminum alloy, a protected barium metal and combinations thereof;
providing an activator species to said one or more source materials or separately;
effecting physical vapour deposition in a sulfur vapour atmosphere of said source materials and said activator species as a thioaluminate phosphor composition on a selected substrate; and
wherein the protected barium metal is a composite of a barium aluminum alloy and an aluminum metal or a barium metal covered with a volatile passivating film.
26. The method of claim 25 , wherein said one or more source materials is an intermetallic barium aluminum compound is selected from the group consisting of BaAl 4 , Ba 7 Al 13 and Ba 4 Al 5 .
27. The method of claim 26 , wherein said intermetallic barium aluminum compound is BaAl 4 .
28. The method of claim 25 , wherein said one or more source materials is a barium aluminum alloy of the formula Ba x Al where x is in the range of about 0.15 to about 0.45.
29. The method of claim 28 , wherein x is in the range of about 0.20 to about 0.35.
30. The method of claim 25 , wherein said one or more source materials is a protected barium metal comprising a composite of a barium aluminum alloy and aluminum metal.
31. The method of claim 25 , wherein said one or more source materials is a protected barium metal comprising 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 31 , wherein said volatile passivating film is a layer of barium oxide, barium sulfate or inert barium compound.
34. The method of claim 25 , wherein said one or more source materials further comprises aluminum metal or aluminum sulfide.
35. The method of claim 25 , wherein said phosphor composition is a barium thioaluminate.
36. The method of claim 25 , wherein said sulfur vapour atmosphere is H 2 S.
37. The method of claim 36 , wherein said sulfur vapour atmosphere is generated remotely from said source materials.
38. The method of claim 37 , wherein said sulfur vapour atmosphere is generated from a polysulfide compound.
39. The method of claim 25 , wherein said deposition is effected by a method selected from sputtering, thermal evaporation and electron beam evaporation.
40. The method of claim 25 , wherein said activator species is selected from europium and cerium.
41. The method of claim 40 , wherein said activator species is europium.
42. The method of claim 40 , wherein said activator species is incorporated within said one or more source materials.
43. The method of claim 40 , wherein said activator species is provided separate from said one or more source materials.
44. A physical vapour deposition method for the deposition of a barium thioaluminate phosphor composition, the method comprising:
providing BaAl 4 as a source material and an activator species; and
effecting vapour deposition of said source material and said activator species as a barium thioaluminate phosphor composition on a selected substrate in a sulfur vapour atmosphere.
45. The method of claim 44 , wherein said sulfur vapour atmosphere is H 2 S.