Formation of nonuniformity in ZnSe/ZnMgSSe quantum well structures during MOVPE on GaAs(001) misoriented by 10° to (111 )_A plane

摘要

ZnSe/ZnMgSSe quantum well structures grown by metal-organic vapor-phase epitaxy on GaAs substrate misoriented from (001) to (111)_A by 10° were studied. Low-temperature cathodoluminescence spectra of these structures showed doubling QW emission lines. The doubling was observed also at addition of Cd, Mg and S in the QWs with concentration of several percents. The reason of this effect was investigated by X-ray reflectometry and diffraction methods. Increasing of scattering with increasing penetration depth was found. It evidences changing QW parameters during the growth. Decomposition of ZnMgSSe solid solution was also observed. The main reason of the doubling was supposed to be due to mutual diffusion of Zn and Mg atoms at QW interfaces. The diffusion is stimulated by relaxation of internal stains or nonuniform distribution of point defects due to the ZnMgSSe decomposition.