MOVPE OF ZNMGSSE HETEROSTRUCTURES FOR OPTICALLY PUMPED BLUE-GREEN LASERS

We report on the growth of ZnMgSSe/ZnSSe/ZnSe heterostructures in a lo w pressure metalorganic vapor phase epitaxy (MOVPE) system at 400 hPa and a growth temperature of 330 degrees C, The precursor combination w as dimethylzinc(triethylamine adduct), ditertiarybutylselenium, ditert iarybutylsulphur, and bismethylcyclopentadienylmagnesium. This combina tion allows the reproducible adjustment of the alloy composition in a wide range (currently up to 40% S and 32% Mg) maintaining high crystal homogeneity and almost lattice matched growth. Undoped separate confi nement heterostructure (SCH) lasers with ZnMgSSe cladding and ZnSSe gu iding layers were deposited on GaBs substrates. X-ray diffraction (rec iprocal space mapping), photoluminescence (PL) at 14-300K, PL excitati on, and optical pumping experiments were performed. The quantum wells show a high luminescence efficiency up to room temperature. Optical pu mping experiments were carried out at various temperatures (77,300-375 K) and excitation densities using a nitrogen laser. The lasing thresho ld could be determined to be less than 20 kW/cm(2) at 77K, and even ro om temperature: lasing was observed at an excitation density which was below 200 kW/cm(2).