ANISOTROPIC RELAXATION DURING THE FIRST STAGES OF THE GROWTH OF ZNTE/(001) CDTE STRAINED LAYERS STUDIED BY REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION

The first stages of the growth of highly strained ZnTe on (001)CdTe are studied by reflection high energy electron diffraction (RHEED) with real-time monitoring of the surface in-plane lattice spacing and of the width of the streaks along the [100], [110], and [11̄0] azimuths. A large, oscillating, elastic relaxation is measured below the critical thickness (≈5 ZnTe monolayers) in the [11̄0] azimuth while a small excess of tensile stress with regard to the CdTe substrate is observed in the [110] azimuth. These effects are attributed to an anisotropic nontetragonal elastic distortion at the free edges of elongated 2D ZnTe-monolayer islands. For large deposition times (i.e., after the critical thickness), the RHEED observation gives very good information about the nature of the dislocations occurring in the multiplication process.© 1995 American Institute of Physics.