Recently

solid state white lighting

optical data storage and biochemical identification applications have led to a tremendous surge in research aimed at developing high power violet and ultraviolet light emitting diodes(V-LEDs and UV-LEDs). The white LEDs have come to be expected for use in lighting

which consists of a blue LEDs and yellow phosphor or an violet(or UV)LED and red-green-blue phosphors

but conversion efficiency and chromaticity of white LED with violet(or UV)LED were better than that with blue LEDs. Although high-brightness blue LEDs have been realized

high-power violet(or UV)LEDs have not yet been realized due to the high dislocation density. One possible reason for this is considered as the suppression of non-radiative recombination center in In xGa 1-xN active layers. It is known for violet(or UV)LEDs that the addition of a small amount of In to GaN active layer results in the improvement of emission wavelength and efficiency. Recently

the epitaxial lateral overgrowth(ELOG)is effective in reducing the dislocation density

so it can be used to fabricate high-power violet(or UV)LED. Violet-LEDs with InGaN/GaN multi-quantum-wells(MQW)structure were grown by low-pressure metalorganic vapor phase epitaxy(LP-MOVPE). The double crystal X-ray diffraction revealed distinct second order satellite peaks. The emitting peak of PL spectra is at 399.5nm with FWHM of about 15.5nm. InGaN/GaN MQW violet-LEDs have been successfully fabricated with forward voltage about 4V at 20mA injection current.