TRANSPARENT CONDUCTIVE OXIDE THIN FILM SUBSTRATE, METHOD OF FABRICATING THE SAME, AND ORGANIC LIGHT-EMITTING DEVICE AND PHOTOVOLTAIC CELL HAVING THE SAME
A transparent conductive oxide thin film substrate that has a high level of surface flatness, a method of fabricating the same, and an OLED and photovoltaic cell having the same. The transparent conductive oxide thin film substrate that includes a base substrate, a first transparent conductive oxide thin film formed on the base substrate, the first transparent conductive oxide thin film being treated with a first dopant, and a second transparent conductive oxide thin film formed on the first transparent conductive oxide thin film. The second transparent conductive oxide thin film is treated with a second dopant at a higher concentration than the first dopant. The surface of the second transparent conductive oxide thin film is flatter than the surface of the first transparent conductive oxide thin film.
1 . A transparent conductive oxide thin film substrate comprising:
a base substrate;
a first transparent conductive oxide thin film formed on the base substrate, the first transparent conductive oxide thin film being treated with a first dopant; and
a second transparent conductive oxide thin film formed on the first transparent conductive oxide thin film, the second transparent conductive oxide thin film being treated with a second dopant at a higher concentration than the first dopant, wherein a surface of the second transparent conductive oxide thin film is flatter than a surface of the first transparent conductive oxide thin film.
2 . The transparent conductive oxide thin film substrate of claim 1 , wherein a content ratio of the first dopant ranges, by weight, from 4.5 to 7.0 percent.
3 . The transparent conductive oxide substrate of claim 2 , wherein a content ratio of the second dopant ranges, by weight, from 7.5 to 9.5 percent.
4 . The transparent conductive oxide thin film substrate of claim 1 , wherein a root mean square (RMS) of a surface roughness of the first and second transparent conductive oxide thin films is 5 nm or less.
5 . The transparent conductive oxide thin film substrate of claim 1 , wherein a sheet resistance of the transparent conductive oxide substrate is 15Ω/□ or less.
6 . The transparent conductive oxide thin film substrate of claim 1 , wherein each of the first dopant and the second dopant is at least one selected from the group consisting of Al, Ga, B, In and F.
7 . The transparent conductive oxide thin film substrate of claim 1 , wherein the first dopant and the second dopant comprises the same substance or different substances.
8 . The transparent conductive oxide thin film substrate of claim 1 , wherein each of the first transparent conductive oxide thin film and the second transparent conductive oxide thin film comprises one selected from the group consisting of In 2 O 3 , ZnO and SnO 2 .
9 . The transparent conductive oxide thin film substrate of claim 1 , wherein each of the first transparent conductive oxide thin film and the second transparent conductive oxide thin film comprises the same substance or different substances.
10 . The transparent conductive oxide thin film substrate of claim 1 , wherein a total of a thickness of the first transparent conductive oxide thin film and a thickness of the second transparent conductive oxide thin film ranges from 150 to 250 nm.
11 . The transparent conductive oxide thin film substrate of claim 1 , further comprising an inner light extraction layer disposed between the base substrate and the first transparent conductive oxide thin film.
12 . The transparent conductive oxide thin film substrate of claim 1 , further comprising an outer light extraction layer disposed on one surface of the base substrate which is opposite the other surface of the base substrate on which the first transparent conductive thin film is formed.
13 . A method of forming a transparent conductive oxide thin film substrate, comprising:
depositing a first transparent conductive oxide thin film on a base substrate, the first transparent conductive oxide thin film being treated with a first dopant; and
depositing a second transparent conductive oxide thin film on the first transparent conductive oxide thin film, the second transparent conductive oxide thin film being treated with a second dopant at a higher concentration than the first dopant.
14 . The method of claim 13 , wherein depositing the first transparent conductive oxide thin film and depositing the second transparent conductive oxide thin film comprise depositing the second transparent conductive oxide thin film on the first transparent conductive oxide thin film in-situ via chemical vapor deposition.
15 . An organic light-emitting device comprising the transparent conductive oxide thin film substrate recited in claim 1 as an anode substrate.
16 . A photovoltaic cell comprising the transparent conductive oxide thin film substrate recited in claim 1 as a transparent electrode substrate.