Claims

1. A light emitting device comprising: an anode for use in light-emission, of polycrystalline silicon; a light emission layer; and a cathode.

2. A light emitting device according to claim 1, wherein the anode is formed by one or more of metal-induced lateral crystallization, metal-induced crystallization of amorphous silicon and laser annealing of amorphous silicon.

3. A light emitting device according to claim 1, wherein the polycrystalline silicon anode is doped.

4. A light emitting device according to claim 3, wherein the polycrystalline silicon anode is doped with at least one of B.sup. and BF_3.sup. .

5. A light emitting device according to claim 1, wherein the polycrystalline silicon anode has a resistance of no more than 10 kΩ/square, preferably no more than 1 kΩ/square.

6. A light emitting device according to claim 1, wherein the polycrystalline silicon anode has an average absorptivity of no more than 30% in the visible light spectrum, preferably around 20%.

7. A light emitting device according to claim 1, wherein the polycrystalline silicon is transparent or translucent.

8. A light emitting device according to claim 1, further comprising a substrate and a buffer layer between the substrate and the anode.

9. A light emitting device according to claim 8, wherein the buffer layer comprises at least one of LTO and SiN_x.

10. A light emitting device according to claim 1, wherein the polycrystalline silicon comprises low temperature polycrystalline silicon.

11. A light emitting device according to claim 1, wherein the polycrystalline silicon comprises thin film polycrystalline silicon.

12. A light emitting device according to claim 11, wherein the thin film polycrystalline silicon is from 10 nm to 300 nm, preferably 30 nm to 100 nm and most preferably about 50 nm thick.

13. A light emitting device according to claim 1, further comprising a transistor having at least a first active island and wherein the polycrystalline silicon anode comprises the first active island of the transistor.

14. A light emitting device according to claim 13, wherein the first active island of the transistor comprises a drain of the transistor.

15. A light emitting device according to claim 13, wherein the transistor further comprises a second active island of the transistor formed of polycrystalline silicon, with the polycrystalline silicon anode.

16. A light emitting device according to claim 13, wherein the transistor further comprises a source which is formed of polycrystalline silicon in the same layer and with the polycrystalline silicon anode.

17. A light emitting device according to claim 13, wherein the transistor is a thin film transistor.

18. A light emitting device comprising an anode, for use in light emission, of polycrystalline silicon.

19. An organic light emitting device comprising: an anode of low temperature polycrystalline silicon; an anode modification layer for holes injection; a plurality of organic layers for electron and hole transport; an organic layer for light emission; and one or more cathode layers.

20. An active matrix light emitting device comprising: an anode for use in light emission; one or more light emission layers; a cathode; and a transistor having at least one active island; wherein the anode comprises an active island of the transistor.

21. An active matrix light emitting device according to claim 20, wherein the anode comprises a polycrystalline silicon anode.

22. An active matrix light emitting device according to claim 21, wherein the at least one active island of the transistor comprises a drain and the polycrystalline silicon anode comprises the drain of the transistor.

23. An active matrix light emitting device according to claim 21, wherein the transistor comprises a second active island of the transistor formed of polycrystalline silicon, with the polycrystalline silicon anode.

24. An active matrix light emitting device according to claim 21, wherein the at least one active island of the transistor comprises a source of the transistor formed of polycrystalline silicon in the same layer and with the polycrystalline silicon anode.

25. An active matrix light emitting device according to claim 20, wherein the transistor is a thin film transistor.

26. An active matrix display comprising an array of pixels, each of a plurality of said pixels comprising: an anode made of low temperature polycrystalline silicon; one or more light emission layers; a cathode; and a thin film transistor.

27. An active matrix display according to claim 26, wherein the thin film transistors comprise active layers of low temperature polycrystalline silicon formed in the same processing step as the anodes.

28. A method of forming a light emitting device comprising: forming an anode of polycrystalline silicon; forming one or more light emission layers; and forming a cathode on the other side of the one or more light emission layers from the anode.

29. A method according to claim 28, wherein forming an anode of polycrystalline silicon comprises one or more of more of metal-induced lateral crystallization, metal-induced crystallization and laser annealing of amorphous silicon.

30. A method according to claim 28, further comprising doping the polycrystalline silicon.

31. A method according to claim 30, further comprising forming an anode modification layer for holes injection and a plurality of organic layers for electron and hole transport between the anode and the one or more light emission layers.

32. A light emitting device according to claim 1, further comprising an anode modification layer for holes injection.

33. A light emitting device according to claim 32, wherein said anode modification layer comprises a thin inorganic layer.

34. A light emitting device according to claim 33, wherein said thin inorganic layer is selected from the group consisting of: V_2O.sub.5, RuO₂, PrO, NiO_x, MoO_x and CuO_x.

35. A light emitting device according to claim 33, wherein said thin inorganic layer has a thickness in the range of 0.5 nm-5 nm.

36. A light emitting device according to claim 32, wherein said anode modification layer comprises an ultra-thin metal layer.

37. A light emitting device according to claim 36, wherein said ultra-thin metal layer is selected from the group consisting of: Pt and Au.

38. A light emitting device according to claim 36, wherein said ultra-thin metal layer has a thickness in the range of 0.5 nm-3 nm.

39. A light emitting device according to claim 32, wherein said anode modification layer comprises a p-type doped organic layer.

40. A light emitting device according to claim 39, wherein said p-type doped organic layer comprises F_4-TCNQ doped m-MTDATA.

41. A light emitting device according to claim 1, further comprising a plurality of organic layers for electron and hole transport, in which the light emission layer is provided.

42. A light emitting device according to claim 41, wherein the plurality of layers, comprise one or more organic layers for light emission.

43. A light emitting device according to claim 1, wherein the cathode comprises one or more layers.

44. A light emitting device according to claim 43, wherein the cathode comprises a monolayer of metal.

45. A light emitting device according to claim 44, wherein the monolayer of metal is selected from the group consisting of an aluminum layer and a silver layer.

46. A light emitting device according to claim 43, wherein the cathode comprises a bi-layer structure.

47. A light emitting device according to claim 46, wherein the bi-layer structure is LiF/aluminum.

48. A light emitting device according to claim 43, wherein the cathode comprises a tri-layer structure.

49. A light emitting device according to claim 47, wherein the tri-layer structure is selected from the group consisting of LiF/Aluminum/Silver and LiF/Calcium/Silver.

50. A light emitting device according to claim 1, further comprising a substrate.

51. A light emitting device according to claim 50, wherein the substrate is transparent or translucent.