Optoelectronic in the blue-UV region based on AlGaN/GaN/InGaN structures is developing rapidly and first DVD players with a 410nm laser diode (LD) inside (Blue Ray Disc, 23 GB) made by Sony are now available in Japan. Nevertheless big problems remain to be solved for nitride laser diodes. One is to go to shorter wavelength than 360nm the other to cover wavelength longer than 480nm. Till now electrically pumped lasing of nitride structures was only possible within this spectral range.
Only ZnSe-based structures have shown lasing between 480 - 560nm. New approaches for stable green lasing will be discussed including CdSe/ZnSSe quantum dot laser and a first monolithic green surface emitting laser (VCSEL). The quantum dot laser shows under constant current degradation a significantly higher long term stability compared to a quantum well LD emitting at the same wavelength.
Another interesting topic is to realize single photon emitter operating at room temperature for quantum information technology and quantum cryptography. Here the II-VI system CdSe/ZnMgSSe has serious advantages compared to the classical III-V compounds like InAs/GaAs.
In the talk the state of art of these different kind of short wavelength light emitters will be presented and critically discussed from the scientific and application point of view. All kinds of laser diodes mentioned above have been realized in Bremen as well as single phonon emitters up to 200K.