Method for forming low emissivity doped zinc oxide films on a substrate

Patent metadata

Field	Value
Publication number	US-2016347654-A1
Application number	US-201515111392-A
Country	US
Kind code	A1
Filing date	Jan 13, 2015
Priority date	Jan 13, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

The invention relates to a method for forming low emissivity doped zinc oxide films on a substrate, and in particular, to a method for forming low emissivity gallium doped zinc oxide films on a substrate via a low temperature chemical bath deposition technique.

First claim

1 . A method for forming a low emissivity doped zinc oxide (ZnO) film on a transparent substrate, comprising:
depositing a ZnO seed layer on the transparent substrate to form a ZnO seeded substrate; immersing the ZnO seeded substrate in a container containing a precursor solution, wherein the precursor solution comprises zinc nitrate hexahydrate, zinc acetate, zinc sulphate, or other zinc containing chemicals dissolved in deionized water, sodium citrate, ammonium citrate, or citric acid, and a dopant for the ZnO film; adjusting the pH of the precursor solution to a range of between 10-12; placing the container in an autoclave and heating the autoclave in an oven at 100° C. or less to deposit doped ZnO film on the transparent substrate; and drying the deposited doped ZnO film.

2 . The method of claim 1 , further comprising annealing the doped ZnO film after drying at between 200° C. and 600° C.

3 . The method of claim 2 , wherein the annealing comprises annealing the doped ZnO film in a box furnace for 1 h in air at 300° C.

4 . The method of any one of claims 1 - 3 , wherein heating the autoclave comprises heating the autoclave in the oven at 90° C.

5 . The method of claim 4 , wherein heating the autoclave comprises heating the autoclave in the oven at 90° C. for 4 h.

6 . The method of any one of claims 1 - 5 , wherein depositing the ZnO seed layer comprises thermal decomposition, atomic layer deposition, sputtering, spin-coating of nanoparticles, or sol-gel deposition.

7 . The method of claim 6 , wherein depositing the ZnO seed layer comprises thermally decomposing zinc acetate, zinc nitrate, zinc sulphate, or other zinc containing chemicals in an oven.

8 . The method of claim 7 , wherein depositing the ZnO seed layer comprises thermally decomposing zinc acetate, zinc nitrate, zinc sulphate, or other zinc containing chemicals in an oven at between 200° C. and 600° C., preferably at 350° C. for 90 min.

9 . The method of any one of claims 1 - 8 , wherein the doped ZnO film is gallium (Ga) doped ZnO film, indium (In) doped ZnO film, or aluminium (Al) doped ZnO film.

10 . The method of claim 9 , wherein the dopant is a gallium salt.

11 . The method of claim 10 , wherein the dopant is gallium nitrate.

12 . The method of any one of claims 1 - 11 , wherein the transparent substrate is borosilicate glass or polycarbonate.

13 . The method of any one of claims 1 - 12 , wherein the pH of the precursor solution is adjusted to 10.9 with a base.

14 . A low emissivity transparent substrate comprising:
a transparent substrate; and a doped zinc oxide (ZnO) film formed on the transparent substrate according to any one of claims 1 - 12 , wherein the doped ZnO film has a film resistivity of at least 10 −3 Ωcm and at most 10 Ωcm.

15 . The low emissivity transparent substrate of claim 14 , having a ratio of visible light transmittance (VLT) to solar heat gain factor (G) (VLT/G) of at least 1.15 and having G of at most 0.61.

16 . The low emissivity transparent substrate of claim 14 or 15 , wherein the doped ZnO film has a carrier concentration of at least 10 19 cm −3 .

Assignees

• Agency Science Tech & Res

Inventors

• Goh Gregory Kia Liang
• Liew Laura-Lynn

Classifications

• C03C2217/216

  ZnO · CPC title

• C23C18/1233

  Organic substrates · CPC title

• C03C2217/24

  Doped oxides · CPC title

• C03C17/245

  by deposition from the vapour phase · CPC title

• C03C2218/32

  After-treatment · CPC title