To obtain a large lattice constant on Si, we have grown compositionally graded Ge x Si1− x
on Si. These buffer layers have been characterized with electron‐beam‐induced current,
transmission electron microscopy, scanning electron microscopy, x‐ray diffraction, and
photoluminescence to determine the extent of relaxation, the threading dislocation density,
the surface morphology, and the optical properties. We have observed that it is possible to
obtain completely relaxed Ge x Si1− x layers with 0.1< x< 1, threading dislocation densities …