A Japanese research team from Riken in Saitama, Waseda University in Tokyo and Tokyo Institute of Technology in Yokohama reported in the Jan. 7 issue of Applied Physics Letters that it has achieved 230- to 280-nm emission from AlGaN-based quantum wells, with efficiencies at 77 K as high as those of InGaN-based quantum wells.

The researchers grew the multiple-quantum-well structures on a SiC substrate using metallorganic vapor phase epitaxy. A xenon lamp producing 215- or 227-nm radiation and a 257-nm argon-ion laser served as the excitation sources for the samples.

They suggest that reducing the threading dislocation density on the AlGaN buffer will improve performance at room temperature. The UV emitters could find applications in optical memory storage and solid-state lighting.