Growth layer for photovoltaic applications

Patent metadata

Field	Value
Publication number	US-9793420-B2
Application number	US-201213261697-A
Country	US
Kind code	B2
Filing date	Feb 3, 2012
Priority date	Feb 4, 2011
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Sputtered zinc oxide layer is used to improve and control the crystalline properties of a molybdenum back contact used in photovoltaic cells. Optimum thicknesses for the zinc oxide layer are identified.

First claim

The invention claimed is:

1. A substrate bearing a stack of layers as the back contact in a molybdenum photovoltaic device, said back contact comprising in order from the substrate:
a barrier layer comprising at least one of: Si x N y , SiO 2 , SnO 2 , SiCO and TiO 2 ;
a primer layer;
a layer of ZnO; and
a layer of molybdenum, wherein the molybdenum is deposited directly on the layer of ZnO;
the ZnO layer having a thickness, t, of 0 nm<t<50 nm;
wherein the ZnO layer is deposited directly on the primer layer; and
the primer layer is deposited directly on the barrier layer and comprises TiO 2 or ZnSnO x .

2. The substrate according to claim 1 , wherein the primer layer has a thickness of between 5 and 50 nm.

3. The substrate according to claim 1 , wherein the substrate is glass.

4. The substrate according to claim 1 , wherein the barrier layer comprises a sodium barrier layer.

5. The substrate according to claim 4 , wherein the barrier layer has a thickness of between 5 and 200 nm.

6. The substrate according to claim 1 , wherein the barrier layer comprises SiO 2 .

7. The substrate according to claim 6 , wherein 8 nm<t<30 nm.

8. The substrate according to claim 7 , wherein 12 nm<t<18 nm.

9. The substrate according to claim 1 , wherein the barrier layer comprises Si x N y .

10. The substrate according to claim 9 , wherein 0 nm<t<30 nm.

11. The substrate according to claim 10 , wherein 0 nm<t<15 nm.

12. The substrate according to claim 11 , wherein 2 nm<t<8 nm.

13. The substrate according to claim 1 , wherein the primer layer comprises a layer of ZnSnO x having a thickness of between 5 and 30 nm.

14. The substrate according to claim 1 , wherein the ZnO layer comprises a component of Al.

15. The substrate according to claim 1 , incorporated in a photovoltaic cell.

16. A substrate bearing a stack of layers as the back contact in a molybdenum photovoltaic device, said back contact comprising in order from the substrate:
a barrier layer;
a layer of ZnO; and
a layer of molybdenum, wherein the molybdenum is deposited directly on the layer of ZnO;
the ZnO layer having a thickness, t, of 0 nm<t<50 nm;
wherein the ZnO layer is deposited directly on the barrier layer; and
the barrier layer comprises at least one of: SnO 2 , SiCO and TiO 2 .

17. The substrate according to claim 16 , incorporated in a photovoltaic cell.

18. A method of controlling the crystal orientation of a molybdenum layer on a substrate comprising the steps of:
depositing a barrier layer comprising at least one of: Si x N y , SiO 2 , SnO 2 , SiCO and TiO 2 on the substrate,
depositing a primer layer comprising TiO 2 or ZnSnO x directly on the barrier layer,
depositing a layer of ZnO directly on the primer layer, and
depositing a layer of molybdenum directly on the layer of ZnO;
wherein a thickness, t, for the ZnO layer is selected according to the desired crystal orientation wherein 0 nm<t<50 nm.

19. The method according to claim 18 , wherein the primer layer has a thickness of between 0 and 50 nm.

20. The method according to claim 18 , wherein the substrate is glass.

21. The method according to claim 20 , wherein the barrier layer comprises a sodium barrier layer on the glass prior to deposition of any other layer.

22. The method according to claim 21 , wherein a thickness is selected for the barrier layer of between 5 and 200 nm.

23. The method according to claim 21 , wherein the barrier layer is deposited by chemical vapour deposition.

24. The method according to claim 18 , wherein the barrier layer comprises a layer of SiO 2 .

25. The method according to claim 24 , wherein 8 nm<t<30 nm.

26. The method according to claim 25 , wherein 12 nm<t<18 nm.

27. The method according to claim 18 , wherein the barrier layer comprises a layer of Si x N y .

28. The method according to claim 27 , wherein 0 nm<t<30 nm.

29. The method according to claim 28 , wherein 0 nm<t<15 nm.

30. The method according to claim 29 , wherein 2 nm<t<8 nm.

31. The method according to claim 18 , wherein the primer layer comprises a layer of ZnSnO x having a thickness of between 5 and 30 nm.

32. The method according to claim 18 , wherein the ZnO layer comprises a component of Al.

Assignees

• Mcsporran Neil
• Pilkington Group Ltd

Inventors

• Mcsporran Neil

Classifications

• H01L31/02021 Primary

  Electricity · mapped topic

• H01L31/0749

  Electricity · mapped topic

• Y02E10/541

  CuInSe2 material PV cells · CPC title

• H01L31/03923

  Electricity · mapped topic

• Y10T428/265

  1 mil or less · CPC title