X-RAY RECIPROCAL SPACE MAPPING OF A (112) ORIENTED HGTE HG0.1CD0.9TE SUPERLATTICE/

Strain in a HgTe/Hg0.1Cd0.9Te superlattice grown on (112)B Cd(0.96)2n( 0.04)Te substrate has been investigated by x-ray reciprocal space mapp ing. It is shown that the shear strain in the superlattice results in monoclinic unit cells, whereas the cubic symmetry of the substrate is retained. The reciprocal lattice points of the superlattice are shifte d by the shear strain such that the conventional analysis fails to int erpret them correctly. Instead, reciprocal space maps should be constr ucted for two azimuths in opposite directions and analyzed simultaneou sly in a coordinate system with nonorthogonal axes. The shear strain i s obtained from the angle between the [(111) over bar] directions of t he superlattice and the substrate, After a position correction taking the measured shear strain into account, longitudinal strains are calcu lated with conventional methods. (C) 1997 American Institute of Physic s.