Phosphor-free white light-emitting diode with laterally distributed multiple quantum wells

A phosphor-free white light-emitting diode (LED) was fabricated with laterally distributed blue and green InGaN/GaN multiple quantum wells (MQWs) grown by a selective area growth method. Photoluminescence and electroluminescence (EL) spectra of the LED showed emission peaks corresponding to the individual blue and green MQWs. The integrated EL intensity ratio of green to blue emission varied from 2.5 to 6.5 with the injection current below 300 mA, but remained constant at high injection currents above 300 mA. The stability of the emission color at high currents is attributed to parallel carrier injection into both MQWs. (C) 2008 American Institute of Physics.