Rapid thermal method and device for thin film tandem cell

1. A method for forming a thin film photovoltaic device, the method comprising:

providing a transparent substrate comprising a surface region;

forming a first transparent electrode layer overlying the surface region of the transparent substrate, the first transparent electrode layer having an electrode surface region

forming a multilayered structure including a copper material and an indium material overlying the electrode surface region;

subjecting the multilayered structure to a plurality of sulfur bearing entities;

subjecting the multilayered structure to a rapid thermal process using a ramp time ranging from about 10 Degrees Celsius/second to about 50 Degrees Celsius/second during the subjecting of the sulfur bearing entities to form an absorber material comprising a copper entity, an indium entity, and a sulfur entity;

forming a cap layer overlying the absorber material;

exposing the cap layer to a solution comprising an etchant;

selectively removing a portion of the cap layer; and

maintaining the first transparent electrode layer to a sheet resistance of less than or equal to about 10 Ohms/square centimeters and an optical transmission of 90 percent and greater.

2. The method of claim 1 further comprising forming a window layer overlying the absorber layer.

3. The method of claim 1 wherein the absorber material comprises a copper indium disulfide material from at least the rapid thermal process of the multi-layered structure, the copper indium disulfide comprising an atomic ratio of copper:indium ranging from about 1:35:1 to about 1:60:1.

4. The method of claim 1 wherein the rapid thermal process having a dwell time of about 1 to 10 minutes at a final temperature ranging from about 400 Degrees Celsius to about 600 Degrees Celsius, and further comprising ramping from the final temperature to a second temperature while subjecting the absorber material to nitrogen gas or argon gas.

5. The method of claim 1 wherein the absorber material is characterized by a band gap energy of about 1.6 to about 1.9 eV.

6. The method of claim 1 wherein the absorber material is selected from a group consisting of : CuInS 2 , Cu(InAl)S 2 , CuInGaS 2 , Cu 2 SnS, or Cu 2 ZnSnS 4 .

7. The method of claim 2 wherein the window layer is selected from a group consisting of a cadmium sulfide, a zinc sulfide, zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO).

8. The method of claim 7 further comprising forming a transparent conductive oxide overlying a portion of the window layer.

9. The method of claim 1 wherein the copper material is provided before the indium material.

10. The method of claim 1 further comprising coupling the thin film photovoltaic device to a second thin film photovoltaic device, the thin film photovoltaic device is a top cell and the second thin film photovoltaic device is a bottom cell.

11. The method of claim 1 wherein the thin film photovoltaic cell is characterized by a conversion efficiency greater than about 8%.

12. A method for forming a thin film photovoltaic device, the method comprising:

providing a transparent substrate comprising a surface region;

forming a first transparent electrode layer overlying the surface region of the transparent substrate, the first transparent electrode layer having an electrode surface region;

forming a window layer overlying the first transparent electrode layer;

forming a multilayered structure including a copper material and an indium material overlying the window layer;

subjecting the multilayered structure to a plurality of sulfur bearing entities;

subjecting the multilayered structure to a rapid thermal process using a ramp time ranging from about 10 Degrees Celsius/second to about 50 Degrees Celsius/second during the subjecting of the sulfur bearing entities to form an absorber material comprising a copper entity, an indium entity, and a sulfur entity;

forming a cap layer overlying the absorber material, the cap layer comprising substantially of copper sulfide material;

exposing the cap layer to a solution comprising an etchant;

selectively removing a portion of the cap layer; and

maintaining the first transparent electrode layer to a sheet resistance of less than or equal to about 10 Ohms/square centimeters and an optical transmission of 90 percent and greater.

13. The method of claim 12 wherein the absorber material comprises a copper indium disulfide material from at least the rapid thermal process of the multi-layered structure, the copper indium disulfide comprising an atomic ratio of copper:indium ranging from about 1:35:1 to about 1:60:1.

14. The method of claim 12 wherein the rapid thermal process having a dwell time of about 1 to 10 minutes at a final temperature ranging from about 400 Degrees Celsius to about 600 Degrees Celsius, and further comprising ramping from the final temperature to a second temperature while subjecting the absorber material to nitrogen gas or argon gas.

15. The method of claim 12 wherein the absorber material is characterized by a band gap energy of about 1.6 to about 1.9 eV.

16. The method of claim 12 wherein the absorber material is selected from a group consisting of : CuInS 2 , Cu(InAl)S 2 , CuInGaS 2 , Cu 2 SnS, or Cu 2 ZnSnS 4 .

17. The method of claim 12 wherein the window layer is selected from a group consisting of a cadmium sulfide, a zinc sulfide, zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO).

18. The method of claim 12 wherein the copper material is provided before t the indium material.

19. The method of claim 12 further comprising coupling the thin film photovoltaic device to a second thin film photovoltaic device, the thin film photovoltaic device is a top cell and the second thin film photovoltaic device is a bottom cell.

20. The method of claim 12 further comprising forming a second electrode layer overlying the absorber material.

21. The method of claim 20 wherein the second electrode layer is comprises a transparent electrode material.

22. The method of claim 12 wherein the thin film photovoltaic cell is characterized by a conversion efficiency greater than about 8%.

23. A method for treating a photovoltaic thin film, the method comprising:

providing a transparent substrate comprising a surface region;

forming a first transparent electrode layer overlying the surface region, the first transparent electrode layer having an electrode surface region;

forming a window layer overlying the first transparent electrode layer;

forming a multilayer structure comprising copper species and indium species overlying the window layer;

subjecting the multilayer structure to a thermal treatment process using a ramp rate about 10 Degrees Celsius per second ramping from room temperature to a first stage at about 250 to 300 Degrees Celsius followed by a second stage at about 475-500Degrees Celsius and a third stage at about 525-550 Degrees Celsius, wherein the thermal treatment process is performed in a sulfur bearing environment for transforming the multilayer structure to a photovoltaic absorber material comprising copper, indium, and sulfur species;

forming a cap layer overlying the photovoltaic absorber material, the cap layer comprising substantially of copper sulfide material;

exposing the cap layer to a solution comprising an etchant;

selectively removing a portion of the cap layer; and

maintaining the first transparent electrode layer to a sheet resistance of less than about 10 Ohms/cm 2 and an optical transmission of 90 percent and greater by controlling dwell time at each of the first stage, the second stage, and the third stage.