PHOTOVOLTAIC DEVICE HAVING IMPROVED BACK ELECTRODE AND METHOD OF FORMATION
A back electrode for a PV device and method of formation are disclosed. A ZnTe material is provided over an absorber material and a MoN x material is provided over the ZnTe material. A Mo material may also be included in the back electrode above or below the MoN x layer and a metal layer may be also provided over the MoN x layer.
1 . A photovoltaic device comprising:
an absorber layer;
an interface layer comprising ZnTe; provided over the absorber layer; and
a back electrode comprising a MoN x layer provided over the ZnTe interface layer.
2 . The photovoltaic device of claim 1 , wherein the back electrode further comprises a Mo layer.
3 . The photovoltaic device of claim 1 , wherein the ZnTe interface layer is doped with Cu.
4 . The photovoltaic device of claim 2 , wherein the MoN x layer is disposed between the ZnTe interface layer and the Mo layer.
5 . The photovoltaic device of claim 2 , wherein the Mo layer is disposed between the ZnTe interface layer and the MoN x layer.
6 . The photovoltaic device of claim 1 , further comprising a window layer below the absorber layer, and wherein the window layer comprises CdS and the absorber layer comprises CdTe.
7 . The photovoltaic device of claim 1 , wherein the MoN x layer comprises Mo 3 N 2 .
8 . The photovoltaic device of claim 1 , wherein the MoN x layer comprises Mo 2 N.
9 . The photovoltaic device of claim 1 , wherein the MoN x layer comprises MoN.
10 . The photovoltaic device of claim 1 , wherein the back electrode has a sheet resistance in the range of about 100 to about 300 ohm-sq.
11 . The photovoltaic device of claim 1 , wherein the back electrode further comprises a metal layer over the MoN x layer.
12 . The photovoltaic device of claim 11 , wherein the metal layer comprises a metal selected from one or more members of the group consisting of aluminum, copper, nickel, gold, silver, or chromium.
13 . The photovoltaic device of claim 1 , further comprising a Cd 1-x Zn x Te layer between the absorber layer and the ZnTe interface layer.
14 . The photovoltaic device of claim 13 , wherein the Cd 1-x Zn x Te layer is doped with copper.
15 . The photovoltaic device of claim 14 , wherein the ZnTe interface layer is doped with copper.
16 . A method of forming a back electrode of a photovoltaic device comprising:
forming a ZnTe material over an absorber layer; and
forming a back electrode comprising a MoN x material over the ZnTe material.
17 . A method as in claim 16 , further comprising forming a Mo material as part of said back electrode.
18 . A method as in claim 16 , further comprising forming a metal material over the MoN x material as part of the back electrode.
19 . A method as in claim 16 , further comprising doping the ZnTe material with Cu.
20 . A method as in claim 17 , wherein the MoN x material is formed between the ZnTe material and the Mo material.
21 . A method as in claim 17 , wherein the Mo material is formed between the ZnTe material and the MoN x material.
22 . A method as in claim 16 , further comprising forming a Cd 1-x Zn x Te layer between the absorber layer and the ZnTe material.
23 . A method as in claim 22 , where the Cd 1-x Zn x Te layer is doped with copper.
24 . A method as in claim 23 , wherein the ZnTe material is doped with copper.
25 . A method of forming a back electrode of a photovoltaic device, comprising:
passing a substrate containing an absorber material on an upper surface through a first deposition chamber and depositing a ZnTe material in said first disposition chamber on the absorber material; and
passing the substrate containing the ZnTe material through a second deposition chamber in which a MoN x material is deposited.
26 . A method as in claim 25 , further comprising passing the substrate including the ZnTe material through a gas separation chamber before passing it to the second deposition chamber.
27 . A method as in claim 26 , further comprising passing the substrate including the deposited MoN x material through a third processing chamber at which a Mo material is deposited.
28 . A method as in claim 27 , further comprising passing the substrate including the MoN x material through a gas separation chamber before passing it through the third processing chamber.
29 . A method as in claim 25 , further comprising passing the substrate comprising the ZnTe material through a third processing chamber at which a Mo material is deposited before passing the substrate containing the ZnTe material through the second processing chamber.
30 . A method as in claim 29 , further comprising passing the substrate containing the Mo material through a gas separation chamber before passing the substrate through the second processing chamber.
31 . A method as in claim 25 , further comprising doping the deposited ZnTe material with copper.
32 . A method as in claim 25 , further comprising forming a window layer below the absorber layer, and wherein the window layer comprises CdS and the absorber layer comprises CdTe.
33 . A method as in claim 25 , wherein the MoN x material comprises Mo 3 N 2 .
34 . A method as in claim 25 , wherein the MoN x layer comprises Mo 2 N.
35 . A method as in claim 25 , wherein the MoN x layer comprises MoN.
36 . A method as in claim 25 , further comprising forming a metal layer over the MoN x layer.
37 . A method as in claim 36 , wherein the metal layer comprises a metal selected from one or more members of the group consisting of: aluminum, copper, nickel, gold, silver, or chromium.
38 . A method as in claim 25 , wherein the ZnTe material is deposited by sputtering.
39 . A method as in claim 25 , wherein the MoN x material is deposited by sputtering.
40 . A method as in claim 27 , wherein the Mo material is deposited by sputtering.
41 . A method as in claim 29 , wherein the Mo material is deposited by sputtering.