METHOD OF FORMING SEMICONDUCTOR FILM AND PHOTOVOLTAIC DEVICE INCLUDING THE FILM
A method of depositing a kesterite film which includes a compound of the formula: Cu 2−x Zn 1+y Sn(S 1−z Se z ) 4+q , wherein 0≦x≦1; 0≦y≦1; 0≦z≦1; −1≦q≦1. The method includes contacting hydrazine, a source of Cu, and a source of at least one of S and Se forming solution A; contacting hydrazine, a source of Sn, a source of at least one of S and Se, and a source of Zn forming dispersion B; mixing solution A and dispersion B under conditions sufficient to form a dispersion which includes Zn-containing solid particles; applying the dispersion onto a substrate to form a thin layer of the dispersion on the substrate; and annealing at a temperature, pressure, and length of time sufficient to form the kesterite film. An annealing composition and a photovoltaic device including the kesterite film formed by the above method are also provided.
1 . A method of depositing a kesterite film comprising a compound of the formula:
Cu 2−x Zn 1+y Sn(S 1−z Se z ) 4+q
wherein 0≦x≦1; 0≦y≦1; 0≦z≦1; −1≦q≦1
said method comprising the steps of:
contacting hydrazine, a source of Cu, a source of Sn, a source of at least one of S and Se, and a source of Zn forming a dispersion comprising Zn-containing solid particles;
applying said dispersion onto a substrate to form a thin layer; and
annealing at a temperature, pressure, and length of time sufficient to form said kesterite film.
2 . The method of claim 1 , wherein said solution further comprises at least one of a solvent, an amine, a polymer, and an additive.
3 . The method of claim 1 , wherein x, y, z and q respectively are: 0≦x≦0.5; 0≦y≦0.5; 0≦z≦1; −0.5≦q≦0.5.
4 . The method of claim 1 , wherein said source of Cu is at least one of Cu 2 S and Cu 2 Se.
5 . The method of claim 1 , wherein said source of Sn is at least one of SnSe, SnS, SnSe 2 , and SnS 2 .
6 . The method of claim 1 , wherein said source of Zn is at least one of metallic zinc, ZnS, and ZnSe.
7 . The method of claim 1 , wherein said source of Zn comprises particles having a particle size from about 2 nm to about 2000 nm and ranges therebetween.
8 . The method of claim 7 , wherein the dimension of said particles are represented by the formula:
d≧2e
wherein d is at least one dimension of said particles; and e is any other dimension of said particles.
9 . The method of claim 1 , wherein said source of S is selected from the group consisting of: elemental sulfur, CuS, Cu 2 S, SnS, SnS 2 , ZnS, and a mixture thereof.
10 . The method of claim 1 , wherein said source of Se is selected from the group consisting of: elemental selenium, SnSe 2 , and SnSe.
11 . The method of claim 1 , wherein said substrate is selected from the group consisting of: metal foil, glass, ceramics, aluminum foil coated with a layer of molybdenum, a polymer, and a combination thereof.
12 . The method of claim 1 , wherein said substrate is coated with a transparent conductive coating.
13 . The method of claim 1 , wherein the step of applying is carried out by a method selected from the group consisting of: spin coating, dip coating, doctor blading, curtain coating, slide coating, spraying, slit casting, meniscus coating, screen printing, ink jet printing, pad printing, flexographic printing, and gravure printing.
14 . The method of claim 1 , wherein the step of annealing is carried out at a temperature from about 200° C. to about 800° C. and ranges therebetween.
15 . The method of claim 1 , wherein said anneal is carried out in an atmosphere comprising:
at least one of: N 2 , Ar, He, forming gas, and a mixture thereof; and optionally
vapors of at least one of: sulfur, selenium, and a compound thereof.
16 . The method of claim 2 , wherein said additive contains a metal, or compound thereof, wherein said metal is selected from the group consisting of: Li, Na, K, Mg, Ca, Sr, Ba, Sb, and Bi, in amount from about 0.01 to about 5 mass %.
17 . The method of claim 1 , wherein the concentration of each of said sources is from about 5 to about 1000 mg/ml.
18 . A method of depositing a kesterite film comprising a compound of the formula:
Cu 2−x Zn 1+y Sn(S 1−z Se z ) 4+q
wherein 0≦x≦1; 0≦y≦1; 0≦z≦1; −1≦q≦1
said method comprising the steps of:
contacting hydrazine, a source of Cu, and a source of at least one of S and Se forming solution A;
contacting hydrazine, a source of Sn, a source of at least one of S and Se, and a source of Zn forming dispersion B;
mixing said solution A and said dispersion B under conditions sufficient to form a dispersion comprising Zn-containing solid particles;
applying said dispersion onto a substrate to form a thin layer; and
annealing at a temperature, pressure, and length of time sufficient to form said kesterite film.
19 . A composition, comprising:
a dispersion of Zn-containing solid particles formed from hydrazine, a source of Cu, a source of Sn, a source of Zn, and a source of at least one of S and Se; which when annealed, forms a compound of the formula: Cu 2−x Zn 1+y Sn(S 1−z Se z ) 4+q wherein 0≦x≦1; 0≦y≦1; 0≦z≦1; −1≦q≦1.
20 . The composition of claim 19 , wherein said solution further comprises at least one of a solvent, an amine, a polymer, and an additive.
21 . The composition of claim 19 , wherein x, y, z and q respectively are: 0≦x≦0.5; 0≦y≦0.5; 0≦z≦1; −0.5≦q≦0.5.
22 . The composition of claim 19 , wherein said source of Zn comprises particles having a particle size from about 2 nm to about 2000 nm and ranges therebetween.
23 . The composition of claim 22 , wherein the dimension of said particles are represented by the formula:
d≧2e
wherein d is at least one dimension of said particles; and
e is any other dimension.
24 . The composition claim 18 , wherein the concentration of each of said sources is from about 5 to about 1000 mg/ml.
25 . A photovoltaic device, comprising:
a top electrode having transparent conductive material;
an n-type semiconducting layer;
a kesterite film on said substrate formed by the method in claim 1 ; and
a substrate having an electrically conductive surface.
26 . A photovoltaic device of claim 25 , wherein:
said substrate is coated with a molybdenum layer and is selected from the group consisting of: glass, plastic, polymer, ceramic, and aluminum foil;
said n-type semiconducting layer has at least one of: ZnS, CdS, InS, oxides thereof, and selenides thereof;
said transparent conductive material is selected from the group consisting of: doped ZnO, Indium-tin oxide, doped tin oxide, and carbon nanotubes.
27 . The photovoltaic device of claim 25 , comprising: a plurality of electrically interconnected photovoltaic devices forming a photovoltaic module.