Transparent Conductive Oxide (TCO) films

Transparent conductive oxide films are widely used in various optoelectronic devices such as flat panel liquid crystal displays, solar cells, energy saving windows, windshields of automobiles and aeroplanes because of their excellent optoelectronic properties such as transparency and low resistivity in the visible region.

TCO film first appeared in the early 20th century, that is, in 1907 Badeker prepared CdO transparent conductive film, around 1950 there was a SnO2-based and In2O3-based transparent conductive film, ZnO-based transparent conductive film in the 20th century, the rise of the 1980s.

Currently the most applied and researched is the tin-doped In2O3 (referred to as ITO) transparent conductive film.

Transparent conductive films of aluminium-doped ZnO (AZO for short) are considered to be the most promising film material.

SnO2-based films

The earliest transparent conductive film with application value is coated with a layer of SnO2 film on the glass, but the pure SnO2 film performance is not as good as the doped SnO2-based film, and is now widely used is doped SnO2 film, the best doping effect is antimony and fluorine.

Antimony-doped SnO2 films are referred to as ATO

Fluorine-doped SnO2 films are referred to as FTO

Phosphorus, arsenic, tellurium, chlorine, etc. can also be used as dopants for SnO2 films.

In2O3-based thin films

Tin-doped In2O3 films (ITO for short) are the most widely researched and applied transparent conductive films, with resistivities between 10-3 and 10-4 Ω-cm and visible light transmission of over 85%.

Numerous literature sources claim that ITO films have optimal optoelectronic properties when the tin doping is 10% (atomic fraction).

Zn-doped ITO films are prepared by DC magnetron sputtering with good etchability and low resistivity.

Mo-doped In2O3-based transparent conductive films IMO were prepared on a glass substrate at 350°C using the conventional reactive evaporation method, which has a resistivity of 1.7 x 10-4 Ω-cm and a visible light transmission of greater than 80%.

ZnO-based thin films

ZnO thin films are now of wide interest due to their abundant raw materials, low cost and excellent performance.

Aluminium-doped ZnO films (AZO) are the best performing ZnO-based films available.

AZO films prepared by magnetron sputtering have resistivities as low as 6.24 x 10-4 Ω-cm and visible light transmission rates greater than 80%.

In order to further improve the chemical stability of AZO films, Cr and Co can be doped in AZO films respectively, 

and the film's corrosion resistance is improved and the same low resistivity can be obtained.

ZnO-based films are currently a popular subject of research, and many scholars at home and abroad are carrying out research work in this area.

Since ITO films contain expensive indium metal, and as the amount of ITO films increases, indium resources will continue to decrease and the cost of ITO films will continue to rise, thus AZO films will become an alternative to ITO films.

related items: ITO sputter target  AZO sputter target  ZnO sputter target