Photovoltaic device and method of formation

Patent metadata

Field	Value
Publication number	US-10026861-B2
Application number	US-201213653051-A
Country	US
Kind code	B2
Filing date	Oct 16, 2012
Priority date	Oct 17, 2011
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

An improved photovoltaic device and methods of manufacturing the same that includes an interface layer adjacent to a semiconductor absorber layer, where the interface layer includes a material in the semiconductor layer which decreases in concentration from the side of the interface layer contacting the absorber layer to an opposite side of the interface layer.

First claim

What is claimed is:

1. A photovoltaic device comprising:
a semiconductor window layer;
a semiconductor absorber layer comprising CdTe adjacent the window layer, the semiconductor window layer and semiconductor absorber layer forming a p-n junction providing an electric field;
an interface layer adjacent to the semiconductor absorber layer comprising a mixture containing Cd, Zn and Te, wherein the interface layer has a first side directly on and facing the absorber layer and a second side; and
a contact layer directly on the second side of the interface layer.

2. The photovoltaic device of claim 1 , wherein the concentration of Zn in the interface layer increases in accordance with a distance away from the first side of the interface layer.

3. The photovoltaic device of claim 1 , wherein the mole ratio of the interface layer is Cd 1-x Zn x Te, where x defines a number between 0 and 1.

4. The photovoltaic device of claim 3 , wherein x defines a number greater than about 0.2.

5. The photovoltaic device of claim 3 , wherein x defines a number greater than about 0.5.

6. The photovoltaic device of claim 3 , wherein x defines a number less than about 0.8.

7. The photovoltaic device of claim 3 , wherein x defines a number less than about 0.5.

8. The photovoltaic device of claim 3 , wherein x defines a number from about 0.2 to 0.3.

9. The photovoltaic device of claim 3 , wherein x defines a number from about 0.6 to 0.8.

10. The photovoltaic device of claim 1 , wherein x defines a number between about 0.8 and 1.

11. The photovoltaic device of claim 3 , wherein x is equal to about 0 at the first side of the interface layer and about 1 at the second side of the interface layer.

12. The photovoltaic device of claim 1 , wherein the interface layer comprises a stack of discrete interface layers, each layer comprising a mixture containing Cd, Zn and Te and each layer having uniform mixture of Cd and Zn, and each layer having a different concentration of Cd and Zn.

13. The photovoltaic device of claim 12 , wherein the mole-to-mole ratio of Cd to Zn in each discrete interface layer decreases incrementally the further away the discrete interface layer is from the semiconductor absorber layer.

14. The photovoltaic device of claim 13 , wherein the mole-to-mole ratio of Cd to Zn in each discrete interface layer is about (1−x):x, where x defines a different number between 0 and 1 for each discrete interface layer.

15. The photovoltaic device of claim 11 , wherein the concentration of Cd and Zn changes continually from said first side of the interface layer to said second side.

16. The photovoltaic device of claim 1 , wherein the concentration of Zn in the interface layer is lower on the first side of the interface layer facing the semiconductor absorber layer and higher on the second side of the interface layer facing the contact layer.

17. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number from 0 to 1.

18. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number greater than about 0.2.

19. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number greater than about 0.5.

20. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number less than about 0.8.

21. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number less than about 0.5.

22. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number from about 0.2 to about 0.3.

23. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number from about 0.6 to 0.8.

24. The photovoltaic device of claim 1 , wherein the mole-to-mole ratio between Cd and Zn throughout the interface layer is about (1−x):x, where x defines a number from about 0.8 to 1.

25. The photovoltaic device of claim 17 , wherein x is equal to about 0 at the first side of the interface layer and about 1 at the second side of the interface layer.

26. The photovoltaic device of claim 16 , wherein the interface layer comprises a stack of discrete interface layers, each layer comprising a mixture containing Cd, Zn and Te and each layer having a uniform mixture of Cd and Zn, each layer having a different concentration of Cd and Zn.

27. The photovoltaic device of claim 26 , wherein the mole-to-mole ratio of Cd to Zn in each discrete interface layer decreases incrementally moving from the semiconductor absorber layer toward the third semiconductor material.

28. The photovoltaic device of claim 27 , wherein the mole-to-mole ratio of Cd and Zn in each discrete interface layer is about (1−x):x, where x defines a different number from 0 to 1 for each discrete interface layer.

29. A photovoltaic device comprising:
a substrate;
a semiconductor window layer;
a semiconductor absorbing layer comprising CdTe over the window layer, the absorber layer and window layer forming a p-n junction producing an electric field;
an intermediate semiconductor interface layer comprising a mixture of Cd and Zn over the semiconductor absorbing layer, wherein the intermediate semiconductor interface has a first side directly on and facing the semiconductor absorbing layer and a second side; and
a contact layer directly on the second side of the intermediate semiconductor interface layer, wherein the concentration of Cd relative to Zn is higher on the first side of the intermediate semiconductor interface layer facing the semiconductor absorbing layer and lower on the second side of the intermediate semiconductor interface layer.

30. The photovoltaic device of claim 26 , wherein the Cd and Zn composition of the intermediate semiconductor interface layer goes from being approximately 70% Cd and 30% Zn at the first side of the intermediate semiconductor interface layer to approximately 30% Cd and 70% Zn at the second side of the intermediate semiconductor interface layer.

31. The photovoltaic device of claim 29 , wherein the Cd and Zn composition of the intermediate semiconductor interface layer goes from being approximately 80% Cd and 20% Zn at the first side of the intermediate semiconductor layer to approximately 20% Cd and 80% Zn at the second side of the intermediate semiconductor interface layer.

32. The photovoltaic device of claim 29 , wherein the Cd and Zn composition of the intermediate semiconductor layer goes from being approximately 90% Cd and 10% Zn at the first side of the intermediate semiconductor interface layer to approximately 10% Cd and 90% Zn at the second side of the intermediate semiconductor interface layer.

33. The photovoltaic device of claim 29 , wherein the Cd and Zn composition of the intermediate semiconductor interface layer goes from being approximately 100% Cd and 0%

Assignees

• First Solar Inc

Inventors

• Sankin Igor
• Gloeckler Markus
• Buller Benyamin
• Tracy Kieran

Classifications

• H10P14/3432

  Tellurides · CPC title

• H10P14/3254

  Graded layers · CPC title

• H10P14/3251

  consisting of three or more layers · CPC title

• H10P14/3241

  being conductive materials · CPC title

• H10P14/3232

  Tellurides · CPC title