Pretreatment of transparent conductive oxide (TCO) thin films for improved electrical contact
Certain embodiments relate to optical devices and methods of fabricating optical devices that pre-treat a sub-layer to enable selective removal of the pre-treated sub-layer and overlying layers. Other embodiments pertain to methods of fabricating an optical device that apply a sacrificial material layer.
1. An optical device comprising:
a substantially transparent substrate;
a lower conductor layer disposed on the substantially transparent substrate; and
a bus bar disposed on the lower conductor layer in a portion of an area of the substantially transparent substrate, wherein a remainder of the area of the substantially transparent substrate has a stack of one or more material layers comprising a sacrificial material layer and/or a sub-layer disposed on top of the lower conductor layer, wherein the remainder of the area of the substantially transparent substrate also has an upper conductor layer disposed on top of the stack of one or more material layers.
2. The optical device of claim 1 , wherein the one or more material layers of the stack comprise a WO 3 electrochromic layer and a nickel-based counter electrode layer.
3. The optical device of claim 2 , wherein the nickel-based counter electrode layer comprises NiWO or NiTaO.
4. The optical device of claim 1 , wherein the optical device is an electrochromic device.
5. The optical device of claim 4 , wherein the sub-layer is on top of, and directly adjacent to, the lower conductor layer of the electrochromic device.
6. The optical device of claim 1 , wherein the lower conductor layer comprises tin oxide.
7. The optical device of claim 1 , wherein the sub-layer comprises a metal oxide, a metal nitride, a metal carbide, a metal oxynitride, or a metal oxycarbide.
8. The optical device of claim 1 , wherein the sub-layer comprises TiO 2 .
9. The optical device of claim 1 , wherein the sub-layer comprises a metal oxide selected from the group consisting of aluminum oxide, titanium oxide, TiO 2 , tantalum oxide, cerium oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungsten oxide, and oxidized indium tin oxide.
10. The optical device of claim 1 , wherein the sub-layer comprises metal nitride selected from the group consisting of titanium nitride, aluminum nitride, silicon nitride, tantalum nitride, and tungsten nitride.
11. The optical device of claim 1 , wherein the sub-layer comprises a metal carbide selected from the group consisting of titanium carbide, aluminum carbide, silicon carbide, tantalum carbide, and tungsten carbide.
12. The optical device of claim 1 , wherein the stack is an electrochromic device stack.
13. The optical device of claim 1 , wherein the sub-layer has higher absorptive properties relative to the lower conductor layer.
14. The optical device of claim 1 , wherein the lower conductor layer comprises SnO 2 .
15. The optical device of claim 1 , wherein the stack comprises a counter electrode layer comprising NiWO or NiTaO.