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 m onitored with reflectance difference spectroscopy. Spectroscopic reflectanc e 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) i nterband transitions of ZnTe, respectively, CdTe, which indicate that aniso tropic 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 de grees dislocations along [1 (1) over bar0] and [110]. Kinetic reflectance d ifference data taken at the E-1 transition of the respective material exhib it with an accuracy of one monolayer the onset of the formation of misfit d islocations for these material systems. (C) 2001 American Institute of Phys ics.