PHOTOPUMPED ZNSE/ZNSSE BLUE SEMICONDUCTOR-LASERS AND A THEORETICAL CALCULATION OF THE OPTICAL GAIN

A ZnSe/ZnSSe blue semiconductor laser was demonstrated to show a very low threshold of about 10 kW/cm2 with photopumping at 300 K, which is equivalent to a current density of 3.8 kA/cm2. The optical gain in ZnSe blue semiconductor lasers was calculated theoretically for various band structures, such as a bulk band structure and a quantum well (QW) structure. In a common cation system such as the ZnSe/ZnSSe heterostructure, the band offset is localized in the valence band and the conduction band is nearly flat. Therefore, the conduction band is bulk-like and the valence band is QW-like. This kind of mixed band structure was also treated. The measured lasing threshold is compared with the calculations and the influence of the carrier confinement on the lasing threshold is discussed.