Study on Micro-structural Properties of PbTe/Cd_(0.98)Zn_(0.02)Te(111) Hetero-system Grown by Molecular-beam Epitaxy

The surface structure of PbTe epitaxial layers on Cd_(0.98)Zn_(0.02)Te(111) grown by molecular beam epitaxy was studied by atomic force microscope.It is shown that the surface is dominated by terraces with triangular shape and anomalous spiral steps.In order to clarify the origin of the triangular shape and spiral steps,PbTe/Cd_(0.98)Zn_(0.02)Te heteroepitaxial layers were investigated by using a high- resolution transmission electron microscope (HRTEM).As a result,it is confirmed that the triangular shape and spiral steps originate from the intrinsic Frank dislocations represented in PbTe/Cd_(0.98)Zn_(0.02)Te interface.Considering the effect of the kinetics of dislocations,it is revealed that the strain field arising from dislocations affects the formation of spiral steps.The experiments data are in agreement with the calculations based on elasticity theory and dislocation gliding theory.