Grazing incidence diffraction by laterally patterned semiconductor nanostructures

A theoretical study of grazing incidence diffraction by laterally patterned epitaxial nanostructures is presented and successfully applied to experime ntal findings of pseudomorphic multilayer gratings. Numerical results from a distorted wave Born approximation are given. The grating structure genera tes a fine structure around the reciprocal lattice points consisting of gra ting truncation rods, which are similar to the crystal truncation rod of a planar crystal surface. We show the influence of the grating shape, the com positional profile and the lattice strain on the intensity pattern along th e grating truncation rods. The effect of lattice strain will be discussed b y comparing the fully strained state (tetragonal lattice distortion), unifo rm strain relaxation and graduated strain relaxation in the surface grating . Our theoretical treatment allows us to interpret grazing incidence diffra ction measurements obtained from strained layer gratings and superlattice g ratings.