350.9 nm UV laser diode grown on sapphire substrate

The combination of a low‐temperature‐deposited AlN interlayer technology and lateral seeding epitaxy (Hetero‐ELO) yielded crack‐free and low‐dislocation‐density AlGaN. The AlGaN over the grooves has a dislocation density as low as 2 × 107 cm–2 due to the lateral growth effect, in contrast with a high dislocation density of 5 × 109cm–2 over terrace region. We demonstrated a UV‐laser diode grown on this low‐dislocation‐density AlGaN. The ridge stripes of the UV‐LD were aligned on this low‐threading‐dislocation‐region. The lasing wavelength under pulsed current injection at room temperature was 350.9 nm. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)