In situ observation of stress relaxation in CdTe/ZnTe heterostructures by reflectance-difference spectroscopy

The first stages of epitaxial growth of CdTe on ZnTe and ZnTe on CdTe are monitored with reflectance difference spectroscopy. Spectroscopic reflectance difference data show strong optical anisotropy responses at the critical points of the bulk dielectric function at the E-0, E-1, and E-1+Delta (1) interband transitions of ZnTe, respectively, CdTe, which indicate that anisotropic in-plane strain occurs during epitaxial growth. Applying a model it is possible to determine the in-plane strain due to the disbalance of 60 degrees dislocations along [1 (1) over bar0] and [110]. Kinetic reflectance difference data taken at the E-1 transition of the respective material exhibit with an accuracy of one monolayer the onset of the formation of misfit dislocations for these material systems. (C) 2001 American Institute of Physics.