Electrodeposition of gallium for photovoltaics

Patent metadata

Field	Value
Publication number	US-9410259-B2
Application number	US-201214240679-A
Country	US
Kind code	B2
Filing date	Sep 4, 2012
Priority date	Sep 2, 2011
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

An electroplating solution and method for producing an electroplating solution containing a gallium salt, an ionic compound and a solvent that results in a gallium thin film that can be deposited on a substrate.

First claim

I claim:

1. An electroplating solution comprising:
a gallium salt;
an ionic compound; and
a solvent, wherein:
the ionic compound is choline chloride (C 5 H 14 ClNO), and
the solvent is ethylene glycol mixed with the ionic compound.

2. The electroplating solution of claim 1 , wherein the gallium salt is selected from the group consisting of gallium chloride, gallium nitrate, gallium sulfate, gallium acetate, gallium fluoride, gallium bromide, and gallium iodide.

3. The electroplating solution of claim 1 , wherein the pH of the solution is between 1 and 3.

4. A method comprising:
electrodepositing a gallium layer from an electroplating solution, wherein:
the electroplating solution comprises a gallium salt, an ionic compound, and a solvent,
the ionic compound is choline chloride (C 5 H 14 ClNO), and
the solvent is ethylene glycol mixed with the ionic compound.

5. The method of claim 4 , wherein the gallium salt is selected from the group consisting of gallium chloride, gallium nitrate, gallium sulfate, gallium acetate, gallium fluoride, gallium bromide, and gallium iodide.

6. The method of claim 4 , further comprising electrodepositing a copper layer on a substrate and electrodepositing an indium layer on the copper layer, prior to the electrodepositing of the gallium layer on the indium layer.

7. The method of claim 6 , further comprising annealing the copper layer, the indium layer, and the gallium layer.

8. The method of claim 7 , wherein the annealing is conducted at a temperature between about 100° C. and about 600° C.

9. The method of claim 7 , wherein the annealing is conducted for a time period between about 10 minutes and about 120 minutes.

10. The method of claim 6 , wherein the substrate comprises at least one of glass, molybdenum, silicon, silicon dioxide, aluminum oxide, sapphire, germanium, gallium arsenide, an alloy of silicon and germanium, or indium phosphide.

11. The method of claim 6 , wherein the substrate is glass coated with a molybdenum film.

12. The method of claim 6 , wherein the atomic percent of gallium in a thin film comprising the copper layer, the indium layer, and the gallium layer is between 0.5% and 30%.

13. The method of claim 6 , wherein the thickness of a thin film comprising the copper layer, the indium layer, and the gallium layer is between about 0.5 microns and about 6 microns.

14. The method of claim 4 , wherein the gallium layer is electrodeposited at a plating current density between 0.1 mA/cm 2 and 5 mA/cm 2 .

15. The method of claim 4 , wherein the gallium layer is electrodeposited at a plating current density between 0.5 mA/cm 2 and 10 mA/cm 2 .

16. The method of claim 4 , wherein the pH of the solution is between 1 and 3.

Assignees

• Bhattacharya Raghu N
• Alliance Sustainable Energy

Inventors

• Bhattacharya Raghu N

Classifications

• H10F77/126

  comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS] · CPC title

• H10F10/166

  the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells · CPC title

• Y02P70/521

  Cross-Sectional Technologies · mapped topic

• Y02E10/541

  CuInSe2 material PV cells · CPC title

• C25D5/54

  Electroplating of non-metallic surfaces (C25D7/12 takes precedence) · CPC title