Cd diffusion in CdS/ZnSe MQW heterostructures grown by MOVPE for semiconductor disk lasers

•Multi quantum well CdS/ZnSe structures are promising for a semiconductor disk laser.•Current probe microscopy can be used to diagnose type II heterostructure.•A depth-non-uniform deformation of quantum wells is observed in the structure.•Interdiffusion of Cd and Zn deteriorates laser performance CdS/ZnSe multi quantum well (MQW) heterostructures with type II band offsets for blue-green semiconductor disk lasers were grown by metalorganic vapor-phase epitaxy (MOVPE) at T = 440 °C. The blurring of heterostructure interfaces during growth is investigated. There has been observed a blueshift of the emission line of heterostructures pumped from the side released from the GaAs substrate, in comparison with the emission line under pumping from the growth surface that indicates the change in the design of QWs during growth. Simulations of experimental X-ray diffraction curves also showed that the average composition of QW changes on CdZnS/ZnCdSe. It is shown that due to the strong mutual diffusion of Cd and Zn through the interfaces, it is possible to form the two ZnSSe/ZnCdSe/ZnCdS QWs with the I-type band offsets. Nevertheless, using light-assisted spreading resistance microscopy measurements on the cleaved cross-sections of the structures, carrier separation in QWs is observed, indicating the formation of a type II band offsets in the most of our heterostructures. The grown structures show intense luminescence, the radiation spectrum of which shifts to the short-wave side with the increase of the pump level.