Synchrotron x-ray study of polycrystalline wurtzite Zn_(1-x)Mg_xO (0 ≤ x ≤ 0.15): Evolution of crystal structure and polarization

摘要

The effect of Mg substitution on the crystal structure of wurtzite ZnO is presented based on synchrotron x-ray diffraction studies of polycrystalline Zn_(1-x)Mg_xO (≤ x ≤ 0.15). Increase in Mg concentration results in pronounced c-axis compression of the hexagonal lattice, and in diminution of the off-center cation displacement within each tetrahedral ZnO_4 unit. Going from ZnO to Zn_(0.85)Mg_(0.15)O, significant changes in the ionic polarization are observed (-5.6 to -4.8 μC/cm~2), despite only subtle increments in the cell volume (～0.03%) and the ab-area dimension (～0.1%).