Silicon goes ultraviolet

The worldwide first silicon-based light emitter for the ultraviolet range is reported from the Forschungszentrum Rossendorf (FZR) in Dresden. In collaboration with nanoparc GmbH, a spin-off of the FZR, scientists from this research center have developed the first light emitting device for ultraviolet light (316 nm) on the basis of silicon technology. Such light is of primary importance for advanced applications especially in the field of biosensors.

Dresden, June 29, 2004. Until the beginning of the nineties silicon was unthinkable to be used as light emitter due to its specific physical properties. Then the colors red and yellow were demonstrated and in the mid-nineties even the most difficult one, blue. During that time, Dr. Wolfgang Skorupa, head of the semiconductor materials research division at the FZR, and his colleagues were successful with a first efficient blue-violet light source emitting at a wavelength of around 400 nm. The present success regarding the UV emitter with a wavelength of 316 nm is clearly based on this early work.

The technology includes ion implantation of rare earth atoms into thin silicon dioxide layers, around which an electrically-driven light-emitting device is fabricated. First tests showed an external quantum efficiency of about 1%. “This is a remarkable output for such devices”, says Wolfgang Skorupa and he is sure that an increase of this value is no problem. The fabrication of the UV-emitting device is based completely on conventional silicon chip technology. This advantage allows for a cheap and simple integration of such light sources into integrated circuits on silicon wafers.

The possibility to connect electrical and optical functions on a single silicon chip is of high current interest for the development of so-called „Lab-on-a-chip“-systems. Such micro-laboratories with quick and cost-efficient abilities to analyse chemical or biological samples are very interesting for bio- and environmental technologies. They allow the analysis of tiny amounts of liquid samples regarding, e.g., pesticides. “This UV light source will be integrated into ´Lab-on-a-chip`-systems for quick point-of-care tests during food control and water monitoring”, as the head of nanoparc GmbH, Dr. Thoralf Gebel, says. These Rossendorf activities experienced strong international recognition and will now be driven ready for the market by nanoparc GmbH.

The worldwide first UV light emitter based on silicon technology:
The strong UV light emitted from the device excites a piece of white paper (right) to blue fluorescence in the visible range (Discothek-Effect). The device was developed in close collaboration between the FZR and its spin-off nanoparc GmbH.

Contact at FZR:
Dr. Wolfgang Skorupa
Institute of Ion Beam Physics and Materials Research
Tel.: ++49 351 260-3612
.
Contact at nanoparc GmbH:
Dr. Thoralf Gebel
nanoparc GmbH, Bautzner Landstr. 45, 01454 Dresden-Rossendorf / Germany
Tel.: ++49 351 269-5350 or 0179 635 6606

Contact for the press:
Dr. Christine Bohnet
Public Relations
Tel.: ++49 351 260 2450
Fax: ++49 351 260 2700

P.O.Box 51 01 19 / 01314 Dresden / Germany