CdZnO OR SnZnO BUFFER LAYER FOR SOLAR CELL
A structure for use in a photovoltaic device is disclosed, the structure includes a substrate, a buffer material, a barrier material in contact with the substrate; and a transparent conductive oxide between the buffer material and the barrier material. The buffer material comprises at least one of CdZnO and SnZnO. The structure can be included in a photovoltaic device. Methods for forming the structure are also disclosed.
1 . A structure for use in a photovoltaic device, the structure comprising:
a substrate;
a buffer material, wherein the buffer material comprises at least one of CdZnO and SnZnO.
a barrier material in contact with the substrate; and
a transparent conductive oxide between the buffer material and the barrier material.
2 . The structure of claim 1 , wherein buffer material further comprises a dopant.
3 . The structure of claim 2 , wherein the dopant comprises a p-type dopant.
4 . The structure of claim 3 , wherein the dopant is selected from the group consisting of: Li, Na, K, N, P, As, Sb, and Bi.
5 . The structure of claim 2 , wherein the dopant comprises an n-type dopant.
6 . The structure of claim 5 , wherein the dopant is selected from the group consisting of: B, Al, Ga, In, T, F, Cl, Br, I, and At.
7 . The structure of claim 2 , wherein the concentration of the dopant is from about 1×10 14 atoms/cm 3 to about 1×10 20 atoms/cm 3 .
8 . The structure of claim 1 , wherein the buffer material has a thickness from about 0.1 nm to about 1000 nm.
9 . The structure of claim 1 , wherein the buffer material has a thickness from about 0.1 nm to about 300 nm.
10 . The structure of claim 1 , wherein the buffer material further comprises at least one other transparent material.
11 . The structure of claim 1 , wherein the buffer material further comprises SnO x .
12 . The structure of claim 1 , wherein the buffer material comprises CdZnO and wherein the atomic ratio of Cd to Zn is from about 1:100 to about 100:1.
13 . The structure of claim 1 , wherein the buffer material comprises SnZnO and wherein the atomic ratio of Sn to Zn is from about 1:100 to about 100:1.
14 . The structure of claim 1 , wherein the substrate is a glass selected from the group consisting of: soda lime glass, low Fe glass and solar float glass.
15 . A photovoltaic device comprising:
a substrate;
a semiconductor material;
a barrier material between the substrate and the semiconductor material;
a transparent conductive oxide between the barrier material and the semiconductor material;
a buffer material between the transparent conductive oxide and the semiconductor material, wherein the buffer material comprises at least one of CdZnO and SnZnO; and
a window material between the buffer material and the semiconductor material.
16 . The device of claim 15 , wherein buffer material further comprises a dopant.
17 . The device of claim 16 , wherein the concentration of the dopant is from about 1×10 14 atoms/cm 3 to about 1×10 20 atoms/cm 3 .
18 . The device of claim 15 , wherein the buffer material has a thickness from about 0.1 nm to about 1000 nm.
19 . The device of claim 15 , wherein the buffer material further comprises at least one other transparent material.
20 . The device of claim 15 , wherein the buffer material comprises CdZnO and wherein the atomic ratio of Cd to Zn is from about 1:100 to about 100:1.
21 . The device of claim 15 , wherein the buffer material comprises SnZnO and wherein the atomic ratio of Sn to Zn is from about 1:100 to about 100:1.
22 . The device of claim 1 , further comprising a contact adjacent the semiconductor material.
23 . The device of claim 15 , wherein the semiconductor material is selected from the group consisting of: CdTe, CIGS and amorphous silicon.
24 . The device of claim 15 , wherein the substrate comprises a glass, the barrier material comprises SiAlO x , the TCO material comprises CdSt, the window material comprises CdS, and the semiconductor material comprises CdTe.
25 . The device of claim 15 , wherein the substrate comprises a glass, the barrier material comprises SnO x and SiAlO x , the TCO material comprises flouring doped SnO 2 , the window material comprises CdS, and the semiconductor material comprises CdTe.
26 . The device of claim 15 , wherein a portion of the buffer material is in direct contact with a portion of the semiconductor material.
27 . A method of making a photovoltaic structure, the method comprising:
providing a substrate;
forming a barrier material on a first side of the substrate;
forming a transparent conductive oxide on the first side of the substrate; and
forming a buffer material on the first side of the substrate, wherein the buffer material comprises at least one of CdZnO and SnZnO; and wherein the barrier material is between the transparent conductive oxide and the substrate; and the transparent conductive oxide is between the buffer material and the barrier material.
28 . The method of claim 27 , further comprising doping the barrier material with a dopant.
29 . The method of claim 28 , wherein the buffer material is formed by a sputtering process, and wherein doping the buffer material comprises using a target having the dopant in a concentration from about 1×10 17 atoms/cm 3 to about 1×10 18 atoms/cm 3 .
30 . The method of claim 27 , wherein at least one of the barrier material, transparent conductive oxide and buffer material are formed by atmospheric physical vapor deposition.
31 . The method of claim 27 , further comprising subjecting the barrier material to a thermal annealing process.
32 . The method of claim 27 , wherein forming the buffer material comprises forming the buffer material in an oxygen deficient environment.
33 . The method of claim 27 , wherein the buffer material is formed in an amorphous state and further comprising processing the buffer material to change at least a portion of the buffer material to a crystalline state.