Method for fabricating CuInS
Disclosed is a method for fabricating a CuInS 2 thin film by metal-organic chemical vapor deposition (MOCVD). The method comprises fabricating a copper thin film by depositing an asymmetric copper precursor on a substrate by MOCVD and fabricating a CuInS 2 thin film by depositing an indium-sulfur-containing precursor on the copper thin film by MOCVD. The method enables fabrication of a CuInS 2 thin film with a constant composition even under vacuum as well as an argon (Ar) atmosphere. Disclosed is further a CuInS 2 thin film fabricated by the method. Disclosed is further a method for fabricating an In 2 S 3 thin film for a window of a solar cell via deposition of an indium-sulfur-containing precursor on the CuInS 2 thin film by MOCVD. Disclosed further is an In 2 S 3 thin film fabricated by the method. The In 2 S 3 thin film is useful for a substitute for CdS conventionally used for windows of solar cells and contributes to simplification in fabrication process of solar cells.
1. A method for fabricating a three-component CuInS 2 thin film comprising:
(1) fabricating a copper thin film by depositing an asymmetric copper precursor selected from the group consisting of copper ethylbutyrylacetate of Formula 1 and copper ethylisobutyrylacetate of Formula 2 on a substrate by metal-organic chemical vapor deposition (MOCVD); and
(2) fabricating a CuInS 2 thin film by depositing an indium-sulfur-containing precursor of Formula (3) on the surface of the copper thin film by metal-organic chemical vapor deposition (MOCVD),
wherein the deposition of the indium-sulfur-containing precursor in the step (2) is carried out a substrate temperature of 350° C. to 430° C., the composition ratio of copper, indium and sulfur components contained in the CuInS 2 thin film is 1:1:2, and the thin film thickness is 0.25 to 5 μm.
2. The method for fabricating a CuInS 2 thin film according to claim 1 , further comprising:
after the step (2), subjecting the CuInS 2 thin film to thermal processing.
3. The method for fabricating a CuInS 2 thin film according to claim 1 , wherein the deposition of the asymmetric copper precursor in the step (1) is carried out under argon atmosphere or vacuum by metal-organic chemical vapor deposition (MOCVD).
4. The method for fabricating a CuInS 2 thin film according to claim 3 , wherein the deposition of the asymmetric copper precursor in the step (1) is carried out under argon atmosphere at a bubbler temperature of 80° C. to 120° C. for the asymmetric copper precursor and a substrate temperature of 320° C. to 360° C. for 2 to 3 hours by metal-organic chemical vapor deposition (MOCVD).
5. The method for fabricating a CuInS 2 thin film according to claim 3 , wherein the deposition of the asymmetric copper precursor in the step (1) is carried out under vacuum at a bubbler temperature of 80° C. to 120° C. for the asymmetric copper precursor and a substrate temperature of 300° C. to 310° C. for 3 to 5 hours by metal-organic chemical vapor deposition (MOCVD).
6. The method for fabricating a CuInS 2 thin film according to claim 1 , wherein the deposition of the indium-sulfur-containing precursor in the step (2) is carried out under argon atmosphere or vacuum by metal-organic chemical vapor deposition (MOCVD).
7. The method for fabricating a CuInS 2 thin film according to claim 6 , wherein the deposition of the indium-sulfur-containing precursor in the step (2) is carried out under argon atmosphere or vacuum at a bubbler temperature of 150° C. to 180° C. for the indium-sulfur-containing precursor for 30 to 300 min by metal-organic chemical vapor deposition (MOCVD).
8. The method for fabricating a CuInS 2 thin film according to claim 1 , wherein the substrate is a glass or an ITO (indium tin oxide) glass.
9. A method for fabricating an In 2 S 3 thin film comprising:
subjecting the CuInS 2 thin film fabricated by the method according to claim 1 to thermal processing at 350° C. to 450° C. for 60 to 180 minutes; and
depositing an indium-sulfur-containing precursor of Formula 3 on the CuInS 2 thin film by metal-organic chemical vapor deposition (MOCVD).
10. The method for fabricating an In 2 S 3 thin film according to claim 9 , wherein the deposition of the indium-sulfur-containing precursor is carried out under argon atmosphere or vacuum at a bubbler temperature of 150° C. to 180° C. for the indium-sulfur-containing precursor and a substrate temperature of 350° C. to 450° C. for 30 to 300 minutes.