Palo Alto Research Center and Crystal IS demonstrate UV-LEDs on AlN substrates
The LED structure consisted of a GaN/AlGaN multiple-quantum-well active region with emission wavelength near 360 nm. The LED devices were 100 microns in diameter with a top p-electrode and a lateral n-contact. The light was extracted through the transparent AlN substrate.
Crystal IS has started supplying research quantities of high-quality AlN substrates and has demonstrated dislocations densities of less than 1000 per sq. cm. AlN substrates offer a very high thermal conductivity (~320 W/m.K), which is important for high power operation of light emitting devices. They also provide good lattice matching particularly for AlGaN active regions with high Al concentrations as required for deep-UV LEDs with emission wavelengths below 300 nm.
Non-polar substrate orientations are also available which may allow improvements in the quantum efficiency of nitride-semiconductor LEDs and laser diodes. An important application of solid-state UV optical sources is anticipated to be compact and highly sensitive bioagent detection systems for airborne pathogens like Anthrax spores. Other potential applications of UV LEDs include solid-state white lighting, sterilization and disinfectant devices, and compact analytical devices for the biotechnology and pharmaceutical markets.
Michael Kneissl of PARC
Tel. +1 650 812 4109
or
Leo Schowalter of Crystal IS
Tel. +1 518 783 0863
Leo@crystal-is.com
E-mail: Michael.Kneissl@parc.com
Web site: http://www.parc.xerox.com
