Progress towards transparent semiconductors

Printed Electronics Review has previously covered the need for highly conductive and high mobility semiconductive transparent materials to be used for displays among other applications. Currently, ITO and ATO are the most commonly used transparent conductors, but are expensive, prone to cracking on a few percent strain (not making them particularly suitable for flexible displays in the main) and are subject to supply demands (See article Wanted! A Transparent Flexible Conductor; Sep 21, 2004.

In the month's edition of Nature, Hideo Hosono at the Tokyo Institute of Technology and his colleagues has developed a transparent semiconductor material which they say has better performance due to a greater mobility of electons when a voltage is applied. The semiconductor material is based on indium gallium zinc oxide. Honso claims prototype transistors made from his team's new material have ten times the performance than silicon transistors used in liquid-crystal displays today.

 

Edzer Huitema of Philips Research Laboratories in Eindhoven, the Netherlands, stated, "This is the first time I've seen a transparent transistor on a plastic substrate with such high performance. This opens up a range of new applications."

 

Indium gallium zinc oxide can be deposited at room temperature rather than high temperatures which means it can be deposited onto cheap, flexible substrates.

 

Transparent circuitry could make existing displays brighter by increasing the amount of light reaching the viewer's eyes.

 

Hosono says that his group is collaborating with an electronics company to develop the technology. Methods for devising mass production presents an industry wide challenge that needs to be addressed next.