InGaN/GaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) with undoped and Si-doped barriers were fabricated. It was found that we could enhance crystal quality of the MQW structure by introducing Si doping into the GaN barrier layers. It was also found that carriers can be injected into the MQW active region more easily for the LED with Si-doped barriers. With a 20 mA injection current, it was found that forward voltages were 3.29 and 3.17 V for the LEDs with undoped barriers and Si-doped barriers, respectively. The output power and external quantum efficiency of the LED with Si-doped barriers were also found to be larger. (c) 2008 The Electrochemical Society.