Iron pyrite thin films from molecular inks

Patent metadata

Field	Value
Publication number	US-9757765-B2
Application number	US-201514728927-A
Country	US
Kind code	B2
Filing date	Jun 2, 2015
Priority date	Jan 18, 2013
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

Systems and methods are provided for fabricating pyrite thin films from molecular inks. A process is provided that comprises dissolving simple iron-bearing and sulfur-bearing molecules in an appropriate solvent and then depositing the solution onto an appropriate substrate using one of several methods (roll-to-roll coating, spraying, spin coating, etc.), resulting in a solid film consisting of the molecules. These molecular precursor films are then heated to 200-600° C. in the presence of sulfur-bearing gases (e.g., S 2 , H 2 S) to convert the molecular films into films of crystalline iron pyrite (FeS 2 ).

First claim

What is claimed is:

1. A method for producing pyrite thin films, comprising the steps of
creating a solution of molecular species comprising iron-bearing and sulfur-bearing molecules;
depositing a thin film of the solution onto a substrate; and
annealing the thin film to convert the molecular species to crystalline iron pyrite, wherein the step of annealing is conducted in an environment containing a sulfur based gas;
wherein the step of creating a solution comprises
adding sulfur and iron powder in a predetermined ratio to ethanolamine and dimethyl sulfoxide (DMSO), and
stirring the sulfur, iron powder, and DMSO as a solution for a time period at a specified temperature.

2. The method of claim 1 , wherein the predetermined ratio is one part ethanolamine in 6.5 parts dimethyl sulfoxide (DMSO).

3. The method of claim 1 , wherein the time period is 24 hours and the specific temperature is room temperature.

4. The method of claim 1 wherein the step of depositing a thin film includes one of roll-to-roll coating, spraying, and spin coating.

5. The method of claim 4 wherein the step of spin coating comprises using spin conditions that yield a thin film having an ˜150 nm thick layer.

6. The method of claim 1 wherein the sulfur based gas is one of S 2 and H 2 S.

7. The method of claim 1 further comprising a step of heating the thin film.

8. The method of claim 7 further comprising a step of cooling the thin film.

9. The method of claim 8 wherein the thin film has a plurality of layers spin coated to achieve a desired film thickness.

10. A method for producing pyrite thin films, comprising the steps of creating a solution of molecular species comprising iron-bearing and sulfur-bearing molecules;
depositing a thin film of the solution onto a substrate;
pre-baking the thin film; and
annealing the thin film in a sulfur atmosphere to convert the molecular species into a pure crystalline iron pyrite film;
wherein the step of creating a solution comprises adding sulfur and iron (Ill) acetylacetonate in a predetermined ratio of pyridine to form the solution.

11. The method of claim 10 further comprising the step of spin coating the solution onto various substrates to make individual solid layers.

12. The method of claim 11 wherein the individual solid layers are ˜200 nm thick.

13. The method of claim 10 wherein the step of depositing a thin film includes one of roll-to-roll coating, spraying, and spin coating.

14. The method of claim 10 wherein the step of annealing includes annealing the thin film at temperatures in a range of 200-600° C. for a plurality of hours to convert the molecular species to crystalline iron pyrite.

15. The method of claim 10 wherein the sulfur atmosphere is one of S 2 and H 2 S.

16. The method of claim 13 wherein the step of spin coating comprises using spin conditions that yield a thin film having an ˜150 nm thick layer.

17. The method of claim 16 further comprising a step of heating the thin film.

18. The method of claim 17 further comprising a step of cooling the thin film.

19. The method of claim 18 wherein the thin film has a plurality of layers spin coated to achieve a desired film thickness.

Assignees

• Univ California

Inventors

• Law Matthew
• Weber Amanda S
• Seefeld Sean
• Puthussery James

Classifications

• H01L31/0336

  Electricity · mapped topic

• B05D1/02

  performed by spraying · CPC title

• Y02P70/521

  Cross-Sectional Technologies · mapped topic

• H01L31/1864

  Electricity · mapped topic

• B05D3/0453

  After-treatment · CPC title