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Optoelectronic Applications

LED Applications

We have developed a method which applies a high epitaxial growth rate to produce thick layers. The Fast Sublimation Growth Process (FSGP) was originally developed to enable growth of high quality epitaxial layers for production of semiconductor devices [1].

The efficiency of the light recombination is critically dependent on the growth method since defects will result in a decreased optical efficiency in the material for the white LED. With FSGP thick doped layers may be grown to produce a voluminous medium from which the dopants act to produce the luminescence.

Today, for realization of white light emitting diodes (LED), a combination of a nitride-based blue LED and coating phosphors is used. However, such white LEDs have a blue cold tone and are not suitable for human’s eyes because they mainly emits blue and yellow light and only a small part of the blue light is converted into yellow one by the phosphor. In addition, the efficiency in the blue LED is decreased at high current densities like needed in general lighting. A new approach is based on all-semiconductor material technology composed of a nitride based ultraviolet-LED excitation source and fluorescent silicon carbide substrate which generate a visible broad spectral light and a pure white light.

This project has a strategic collaboration with Meijo University.

Read more on www.liu.se/senmat

[1] M. Syväjärvi and R. Yakimova: “ Sublimation epitaxial growth of hexagonal and cubic SiC”, Elsevier, chapter in encyclopedia - the Comprehensive Semiconductor Science & Technology (SEST), Pallab Bhattacharya, Roberto Fornari and Hiroshi Kamimura (Eds), ISBN 978-0-444-53144-5 (2011).

 


Responsible for this page: Fredrik Karlsson
Last updated: 07/04/12