1) Researchers fabricated ultraviolet light emitting diodes that operate at a wavelength of 346 nm, the shortest reported at the time. 2) This was achieved by using a strain-reduced multi-quantum well structure of AlGaN/AlGaN to reduce the piezoelectric field effects that deteriorate emission efficiency at short wavelengths. 3) Electroluminescence measurements showed a dominant emission peak at 346 nm with a narrow full width at half maximum of 5 nm, demonstrating efficient band-edge emission at this short wavelength.