Blue-green laser diodes

The current status, as well as some key issues related to the growth and characterization of II-VI blue/green laser diodes are reviewed. The Zn(Se,Te) graded contact to p-ZnSe is effective in supporting the room-temperature CW operation of green (508 nm) laser diodes while device lifetimes are currently limited by the formation of dark defects in the active region. The role of extended and point defects in degradation will be discussed. Additional problems have arisen in the move to shorter wavelengths. For example, an observed increase of resistivity with increased bandgap energy has been associated with the formation of AX centers, a DX like behavior for acceptors.