Lattice deformation of wurtzite MgxZn1−xO alloys: An extended X-ray absorption fine structure study

Synchrotron extended X-ray absorption fine structure (EXAFS) of Zn K-edge and X-ray diffraction (XRD) have been employed to study the lattice deformation of wurtzite MgxZn1−xO alloys (0 ⩽ x ⩽ 0.14) grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD). Our results reveal that Mg concentration increasing leads to the enhancement of σ-bonding of Zn–O and lattice constant a while resulting in depression of π-bonding of Zn–O and lattice constant c. With increasing from x = 0 to x = 0.14, the c/a ratio significantly decreases from 1.6014 to 1.5906, while the internal parameter u decreases only slightly from 0.3826 to 0.3820. This suggests that the u has a much smaller sensitivity for dilute Mg substitution.