Blue and blue/green laser diodes and LED-based display devices

The authors discuss the electrical and optical characteristics of new LED (light emitting diodes) and laser structures where the II-VI region consists of the alloy Zn(S,Se) in which six (Zn,Cd)Se quantum wells are embedded. Both passive waveguide studies and optically pumped laser experiments have shown that the MQW (multiple quantum well) region provides sufficient optical waveguiding in the region, while providing strong confinement of both holes and electrons in the wells. The addition of sulfur to the barriers and the appropriate selection of the Cd fraction in the wells result in an emission wavelength in the blue portion of the spectrum (490-494 nm) at room temperature.