RECOMBINATION MECHANISMS IN PHOTOPUMPED ZN1-XCDXSE ZNSE MULTIPLE-QUANTUM-WELL LASERS/

We investigated exciton stability and the recombination mechanism resp onsible for lasing in Zn1-xCdxSe/ZnSe multiple quantum well structures grown by molecular beam epitaxy. We used photocurrent measurements as a function of sample composition and temperature to gauge exciton sta bility, and photoluminescence and magne tophotoluminescence spectrosco py to identify the recombination channels associated with stimulated e mission. For relatively shallow quantum wells (x similar to 0.10), the spontaneous emission line shifts diamagnetically with the magnetic fi eld as expected for exciton-related transitions. On the contrary, the stimulated emission exhibits a linear shift with the magnetic field wh ich is consistent with free-carrier recombination from Landau levels.