Solution processing of kesterite semiconductors

Patent metadata

Field	Value
Publication number	US-9252304-B2
Application number	US-201213644672-A
Country	US
Kind code	B2
Filing date	Oct 4, 2012
Priority date	Oct 4, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Methods for 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, generally include contacting a hydrazine-based solvent, a source of Cu, a source of Sn, a source of Zn carboxylate, a source of at least one of S and Se, under conditions sufficient to form a solution substantially free of solid particles; applying the solution onto a substrate to form a thin layer; and annealing the thin layer at a temperature, pressure, and length of time sufficient to form the kesterite film. Also disclosed are hydrazine-based precursor solutions for forming a kesterite film and a photovoltaic device including the kesterite film formed by the above method.

First claim

What is claimed is:

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:
contacting a hydrazine-based solvent, a source of Cu selected from the group consisting of Cu, Cu 2 S and Cu 2 Se, a source of Sn selected from the group consisting of Sn, SnS, SnS 2 , SnSe, and SnSe 2 , a source of Zn carboxylate, a source of at least one of S and Se, under conditions sufficient to form a solution free of solid particles, wherein the conditions consist of dispersing the source of the zinc carboxylate in a portion of the hydrazine-based solvent to form a first slurry of zinc carboxylate particles, and dispersing the source of Sn in a portion of the hydrazine-based solvent to form an initial Sn solution, and mixing the first slurry and the initial Sn solution to dissolve the zinc carboxylate particles and form the solution free of solid particles, wherein the source of Cu, and the source of at least one of S and Se are added to the initial Sn solution or to the solution free of solid particles;
applying the solution free of solid particles onto a substrate to form a thin layer having a thickness of about 0.2 microns to about 5 microns; and
annealing the thin layer at a temperature, pressure, and length of time sufficient to form the kesterite film.

2. The method of claim 1 , wherein said hydrazine-based solvent comprises hydrazine in an amount from about 1 weight % to about 99 weight % by total weight of the solvent.

3. The method of claim 1 , wherein said source of Zn carboxylate is at least one of zinc formate and zinc acetate.

4. The method of claim 1 , wherein said source of S or Se is at least one of S and Se.

5. The method of claim 1 , wherein said solution substantially free of particles further comprises at least one additive each containing a metal selected from the group consisting of: Li, Na, K, Mg, Ca, Sr, Ba, Sb, Bi, and a combination thereof.

6. The method of claim 5 , wherein said metal is present in an amount from about 0.01 weight % to about 5 weight % by total weight of the solution substantially free of particles.

7. The method of claim 1 , wherein said hydrazine-based solvent further comprises an organic solvent from about 1 weight % to about 99 weight % by total weight of the solvent.

8. The method of claim 1 , wherein said hydrazine-based solvent further comprises an inorganic solvent different from hydrazine from about 1 weight % to about 99 weight % by total weight of the solvent.

9. 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.

10. 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.

11. The method of claim 1 , wherein said substrate is coated with a transparent conductive coating.

12. The method of claim 1 , wherein the applying the solution substantially free of solid particles 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.

13. The method of claim 1 , wherein the annealing is carried out at a temperature from about 200° C. to about 800° C. and ranges there between.

14. The method of claim 1 , wherein the annealing is carried out in an atmosphere comprising: at least one of: N 2 , Ar, He, forming gas, and a mixture thereof.

Assignees

• IBM

Inventors

• Todorov Teodor K

Classifications

• C08K5/098

  Metal salts of carboxylic acids · CPC title

• C08K3/28

  Nitrogen-containing compounds · CPC title

• C08K3/02

  Elements · CPC title

• H10F77/244

  made of transparent conductive layers, e.g. transparent conductive oxide [TCO] layers · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title