Liquid precursor for deposition of copper selenide and method of preparing the same
View Patent ↗Liquid precursors containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semiconductor applications are disclosed. Methods of preparing such liquid precursors and methods of depositing a precursor on a substrate are also disclosed.
1. A method of preparing a liquid copper selenide precursor, the method comprising: reducing elemental selenium with a stoichiometric amount of hydrazine in the presence of a first solvent to yield a first solution comprising Se 2 2− ; and combining the first solution with a second solution comprising a copper salt and a second solvent to yield the liquid copper selenide precursor comprising soluble CuSe 2 , wherein the liquid copper selenide precursor is essentially hydrazine-free.
2. The method of claim 1 , wherein at least one of the first solvent or the second solvent comprises a primary amine or a secondary amine.
3. The method of claim 1 , wherein at least one of the first solvent or the second solvent comprises at least one of ethylene diamine, ethanolamine, or diethylene triamine.
4. The method of claim 3 , wherein at least one of the first solvent or the second solvent is ethylene diamine.
5. The method of claim 1 , wherein the copper salt comprises at least one of copper chloride, copper bromide, copper iodide, copper acetate, copper formate, copper nitrate, or copper trifluoromethanesulfonate.
6. The method of claim 1 , further comprising separating any precipitate formed during the combining.
7. The method of claim 6 , wherein the separating comprises at least one of filtration or centrifugation.
8. The method of claim 1 , wherein the liquid copper selenide precursor comprises copper having a concentration between 0.08 M and 0.10 M.
9. A method of depositing a solid copper selenide precursor on a substrate, the method comprising:
applying the liquid copper selenide precursor prepared by the method of claim 1 to the substrate; and
heating the liquid copper selenide precursor to a temperature and for a time sufficient to yield the deposited solid copper selenide precursor on the substrate.
10. The method of claim 9 , wherein the deposited solid copper selenide precursor is a thin film.
11. The method of claim 9 , wherein the temperature is at least 50° C.
12. The method of claim 11 , wherein the temperature is between 50° C. and 275° C.
13. The method of claim 9 , wherein the deposited solid copper selenide precursor comprises CuSe 2 .
14. The method of claim 9 , wherein the applying comprises at least one of drop coating, dip coating, spin coating, spraying, brushing, air brushing, ink jet application, stamping, printing, pouring, wiping, smearing, spray deposition, or slot coating.
15. The method of claim 9 , wherein the liquid copper selenide precursor comprises copper having a concentration between 0.08 M and 0.10 M.