Photovoltaic Devices Including Nitrogen-Containing Metal Contact

1 . A method of manufacturing a photovoltaic cell comprising:

forming a first semiconductor layer over a substrate, wherein the first semiconductor layer comprises CdTe, CdSe, or mixtures thereof;

forming a second layer over the first semiconductor layer, wherein the second layer comprises CdO;

depositing a metal layer over the second layer in the presence of nitrogen to form a nitrogen-containing metal layer in contact with the second layer, wherein the nitrogen-containing metal layer includes an aluminum nitride, a molybdenum nitride, a nickel nitride, a titanium nitride, a tungsten nitride, a selenium nitride, a tantalum nitride, or a vanadium nitride;

depositing an aluminum layer over the nitrogen-containing metal layer; and

depositing a chromium layer over the aluminum layer.

2 . The method of claim 1 , further comprising:

placing a transparent conductive layer on the substrate; and

placing a capping layer between the transparent conductive layer and the first semiconductor layer.

3 . The method of claim 1 , wherein the step of depositing the metal layer over the second layer in the presence of nitrogen further comprises: sputtering in a nitrogen gas mixture comprising 2% to 50% nitrogen.

4 . The method of claim 1 , wherein the step of depositing the metal layer over the second layer in the presence of nitrogen further comprises: sputtering in a nitrogen argon gas mixture composed of 13% nitrogen and 87% argon.

5 . The method of claim 1 , wherein the nitrogen-containing metal layer comprises an atomic percent nitrogen in a range between 1 percent and 50 percent.

6 . The method of claim 1 , wherein the nitrogen-containing metal layer comprises an atomic percent nitrogen greater than 50 percent.

7 . The method of claim 1 , further comprising transporting the substrate into a series of one or more deposition stations on a conveyor, wherein at least one deposition station comprises a deposition chamber heated to a processing temperature in a range from about 450° C. to about 700° C.

8 . The method of claim 1 , wherein the nitrogen-containing metal layer includes a non-stoichiometric nitride.

9 . A method of manufacturing a photovoltaic cell comprising:

forming a first semiconductor layer over a substrate, wherein the first semiconductor layer comprises CdTe, CdSe, or mixtures thereof;

forming a second semiconductor layer over the first semiconductor layer, wherein the second semiconductor layer comprises Zn;

depositing a metal layer over the second semiconductor layer in the presence of nitrogen to form a nitrogen-containing metal layer, wherein the nitrogen-containing metal layer includes an aluminum nitride, a molybdenum nitride, a nickel nitride, a titanium nitride, a tungsten nitride, a selenium nitride, a tantalum nitride, or a vanadium nitride;

depositing an aluminum layer over the nitrogen-containing metal layer; and

depositing a chromium layer over the aluminum layer.

10 . The method of claim 9 , wherein the second semiconductor layer comprises ZnTe.

11 . The method of claim 9 , wherein the second semiconductor layer comprises ZnSe.

12 . The method of claim 9 , wherein the second semiconductor layer comprises ZnO.

13 . The method of claim 9 , wherein the nitrogen-containing metal layer comprises titanium nitride.

14 . The method of claim 9 , wherein the nitrogen-containing metal layer comprises molybdenum nitride.

15 . The method of claim 9 , wherein the step of depositing the metal layer over the second layer in the presence of nitrogen further comprises: sputtering in a nitrogen gas mixture comprising 2% to 50% nitrogen.

16 . The method of claim 9 , wherein the nitrogen-containing metal layer comprises an atomic percent nitrogen greater than 50 percent.

17 . A method of manufacturing a photovoltaic cell comprising:

forming a first semiconductor layer over a substrate, wherein the first semiconductor layer comprises CdTe, CdSe, or mixtures thereof;

forming a second semiconductor layer over the first semiconductor layer, wherein the second semiconductor layer comprises ZnTe;

depositing a metal layer over the second semiconductor layer in the presence of nitrogen to form a nitrogen-containing metal layer in contact with the second semiconductor layer, wherein the nitrogen-containing metal layer includes an aluminum nitride, a molybdenum nitride, a nickel nitride, a titanium nitride, a tungsten nitride, a selenium nitride, a tantalum nitride, or a vanadium nitride.

18 . The method of claim 17 , further comprising:

placing a transparent conductive layer on the substrate; and

placing a capping layer between the transparent conductive layer and the first semiconductor layer.

19 . The method of claim 18 , wherein the transparent conductive layer comprises tin oxide.

20 . The method of claim 17 , wherein the nitrogen-containing metal layer comprises titanium nitride.