High-performance 407 nm violet InGaN multi-quantum-wells fight-emitting diodes (LED) with an un-doped GaN current spreading layer were fabricated on sapphire substrate by using metal organic chemical vapor deposition technique. Different conditions were chosen to grow un-doped GaN layer as the current spreading layer in three LEDs. Using a 30 mat high-temperature un-doped GaN layer, the output efficiency and high injection current luminance versus current (I-L) characteristics of our LED have been greatly improved. A LED with an output power of 7 mW at an injection current of 20 mA was achieved. In additional, the LED also shows an almost linear I-L characteristics at high injection current. (C) 2004 Elsevier B.V. All rights reserved.