X-ray Reciprocal Space Mapping of Graded Al x Ga1 − x N Films and Nanowires

Abstract

The depth distribution of strain and composition in graded AlxGa1 − xN films and nanowires (NWs) are studied theoretically using the kinematical theory of X-ray diffraction. By calculating reciprocal space maps (RSMs), we demonstrate significant differences in the intensity distributions from graded AlxGa1 − xN films and NWs. We attribute these differences to relaxation of the substrate-induced strain on the NWs free side walls. Finally, we demonstrate that the developed X-ray reciprocal space map model allows for reliable depth profiles of strain and Al composition determination in both AlxGa1 − xN films and NWs.