A new power diode has been developed in Japan which could provide a significant boost in the drive to make hybrid cars more efficient, it was confirmed on Thursday (8th January).

The device, which was developed by the country's National Institute of Advanced Industrial Science and Technology (AIST), is designed to be used in power semiconductor systems.

Although diodes of this type have traditionally been made from gold or platinum electrodes on a diamond substrate, the newest addition has been constructed from ruthenium.

The metal is viewed as an improvement - although the device can only handle a current of one ampere at present - as gold and platinum tend to react with the substrate and peel off, rendering diodes unusable.

According to AIST, the new diode is capable of operating for a total of 1,500 hours at a temperature of 400C - an improvement on the previous requirement to cool it down to 250C.

It is hoped that, following further tests to increase their performance, the diodes could be placed in the engines of hybrid vehicles, thus eliminating the need to install a cooling system.

Source:

New power device diode brings dream of more efficient hybrid cars closer (09/01/08)
http://www.crunchgear.com/2009/01/09/new-power-device-diode-brings-dream-of-more-efficient-hybrid-cars-closer/