Coated article having low-E coating with IR reflecting layer(s) and niobium bismuth based high index layer and method of making same
A coated article includes a low emissivity (low-E) coating on a glass substrate. The low-E coating includes at least one infrared (IR) reflecting layer of a material such as silver, gold, or the like, and at least one high refractive index layer of or including NbBi. The high index layer (e.g., NBBiO x ) is designed and deposited so as to be amorphous in the low-E coating, so as to better withstand optional heat treatment (HT) such as thermal tempering. The high index layer may be a transparent dielectric high index layer.
1. A coated article including a coating supported by a glass substrate, the coating comprising:
a first transparent dielectric layer on the glass substrate;
an infrared (IR) reflecting layer comprising silver on the glass substrate, located over at least the first transparent dielectric layer;
a second transparent dielectric layer on the glass substrate, located over at least the IR reflecting layer; and
wherein at least one of the first and second transparent dielectric layers is amorphous or substantially amorphous, and comprises an oxide of Nb and Bi wherein the metal content of the oxide of Nb and Bi is from 55-99% Nb and from 1-45% Bi (atomic %).
2. The coated article of claim 1 , wherein the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi comprises a suboxide of Nb and Bi.
3. The coated article of claim 1 , wherein the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi has a refractive index (n) of at least 2.2.
4. The coated article of claim 1 , wherein the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi has a refractive index (n) of at least 2.25.
5. The coated article of claim 1 , wherein the first transparent dielectric layers is amorphous or substantially amorphous, and comprises the oxide of Nb and Bi.
6. The coated article of claim 1 , wherein the second transparent dielectric layers is amorphous or substantially amorphous, and comprises the oxide of Nb and Bi.
7. The coated article of claim 1 , wherein the coating is a low-E coating and has a normal emissivity (E n ) of no greater than 0.2.
8. The coated article of claim 1 , wherein the coating has a sheet resistance (R s ) of no greater than 9 ohms/square.
9. The coated article of claim 1 , wherein the coating comprises an overcoat including a layer comprising tin oxide and a layer comprising silicon nitride.
10. The coated article of claim 1 , wherein the coating further comprises a layer comprising silicon nitride located between at least the glass substrate and the first transparent dielectric layer.
11. The coated article of claim 1 , wherein the coating further comprises a layer comprising zinc oxide located under and directly contacting the IR reflecting layer.
12. The coated article of claim 1 , wherein the coating further comprises a layer comprising an oxide of Ni and/or Cr located over and directly contacting the IR reflecting layer.
13. The coated article of claim 1 , wherein the coated article is thermally tempered.
14. The coated article of claim 1 , wherein the coated article has a visible transmission of at least 50%.
15. The coated article of claim 1 , wherein metal content of the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi is from 60-95% Nb and from 5-40% Bi (atomic %).
16. The coated article of claim 1 , wherein metal content of the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi is from 70-90% Nb and from 10-30% Bi (atomic %).
17. A method of making a coated article including a coating supported by a glass substrate, the method comprising:
sputter depositing a first transparent dielectric layer on the glass substrate;
sputter-depositing an infrared (IR) reflecting layer comprising silver on the glass substrate, located over at least the first transparent dielectric layer;
sputter-depositing a second transparent dielectric layer on the glass substrate, located over at least the IR reflecting layer; and
wherein at least one of the first and second transparent dielectric layers is sputter-deposited so as to be amorphous or substantially amorphous, and comprise an oxide of Nb and Bi wherein the metal content of the oxide of Nb and Bi is from 55-99% Nb and from 1-45% Bi (atomic %).
18. The method of claim 17 , wherein the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi is sputter-deposited so as to comprise a suboxide of Nb and Bi.
19. The method of claim 17 , wherein the at least one of the first and second transparent dielectric layers comprising an oxide of Nb and Bi has a refractive index (n) of at least 2.2.
20. The method of claim 17 , wherein the at least one of the first and second transparent dielectric layers sputter-deposited so as to be amorphous and comprise and oxide of Nb and Bi is sputter-deposited in an oxygen depleted atmosphere so that a difference in cationic radii for Nb and Bi causes lattice disorder leading to amorphous or substantially amorphous structure of the layer.
21. The method of claim 17 , wherein the at least one of the first and second transparent dielectric layers sputter-deposited so as to comprise an oxide of Nb and Bi is sputter-deposited using at least one ceramic target comprising Nb, Bi and O.
22. The method of claim 17 , wherein the at least one of the first and second transparent dielectric layers sputter-deposited so as to comprise an oxide of Nb and Bi is sputter-deposited using at least one metallic target comprising Nb and Bi.
23. The method of claim 17 , wherein the coating is a low-E coating and has a normal emissivity (E n ) of no greater than 0.2.
24. The method of claim 17 , further comprising thermally tempering the glass substrate with the coating thereon.
25. The method of claim 17 , wherein the coated article has a visible transmission of at least 50%.