Quantitative growth-investigation of zincblende ZnMgSe/GaAs(0 0 1) and ZnSe/GaAs(0 0 1) by means of RHEED, HRXRD and thickness monitoring

We report on reflection high energy electron diffraction (RHEED), high resolution X-ray diffraction (HRXRD) and thickness monitoring measurements of molecular beam epitaxy (MBE) grown ZnSe/GaAs (0 0 1) and Zn1-χMgχSe/ GaAs (0 0 1) samples. We measured the particle flux rates with a thickness monitor prior to growth and used RHEED intensity oscillations during growth of ZnSe and Zn1-χMgχSe for calculating the number of incorporated atoms. Thereby we accurately determined the sticking coefficients of Zn and Mg dependent on the VI : II-flux ratio and growth temperature. We show the lattice relaxation of metastable zincblende MgSe/GaAs(0 0 1) by RHEED and determine for the first time the in-plane lattice constant of MgSe. The Mg content χ in Zn1-χMgχSe/ZnSe/GaAs (0 0 1) (χ < 0.37) is calculated from the relative difference in growth rates measured by RHEED. These results agreed very well with high resolution X-ray diffraction (HRXRD) measurements for growth under Se-rich conditions, whereas a strong disagreement was recognized under cation-rich conditions.