Power Management DesignLine Blog
What power development would you invest in?
Paul Buckley
9/29/2008 9:07 AM EDT
But are there any real contenders out there that will have a major impact in the future?
What is going to become the new lithium-ion battery for the next decade? Or what will be the new HEXFET?
So far this year have we seen any developments that promise to become a market leading technology in the power management arena during the next ten years?
Solar cells
Well on a topical note, Mitsubishi Electric announced last week it has developed a way to fabricate polycrystalline-silicon-type solar cells that convert light energy to electrical energy with an efficiency of 18.6 per cent, 0.3 percentage points above the previous record.
The prototype solar cell is 15cm square and 180 microns thick. The surface has a honeycomb structure that reduces reflectivity and keeps more of the light from escaping once it has entered the device. The electrodes are half the usual thickness at 60 microns, but also twice as tall. This broadens the surface area for generating electrons without boosting electrical resistance.
The company expects to commercialize solar cells based on this technology in 2010.
The Mitsubishi advance certainly has the benefit of a major corporation supporting the development but perhaps you may believe that a better long-term contender hails from the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg which recently surpassed its own European multi-junction III-V solar cell efficiency record, recently reaching 37.6 percent.
The new record of 39.7 percent was achieved using a front-side network of thin metal wires that transport large currents but with low resistance.
The solar cell structures consist of more than 30 single layers, which are deposited on a germanium substrate by means of metal-organic vapour-phase epitaxy (MOVPE).
GaN power devices
In the area of power devices the one breakthrough technology looks like being gallium nitride power devices. International Rectifier plans to begin shipping GaN as early as 2009 while a number of other companies are known to be developing GaN solutions including Sharp, Oki, Matshushita, Fuji Electric, Toshiba, Toyota and STMicroelectronics.
The use of GaN-on-silicon epitaxial technology looks like being the key to the viability of this technique. The new devices promise performance improvements up to ten times that of existing devices with the main applications including AC/DC and DC/DC conversion, as well as Class D audio.

