an decrease of the lattice constant which is due to the fact that the
ionic radius of Mg2+ (0.57 Å) is smaller than that of Zn2+ (0.60 Å)
[14]. Using Bragg’s equation: k ¼ 2d sin h and the lattice geometry
equation [26], we can learn that the a-axis and c-axis lattice constants
decrease from 3.261 and 5.233 Å to 3.241 and 5.202 Å with
the increase of Mg content from 0 to 5.01 at.%, respectively. From
Fig. 4(b), it will be also noted that the (002) peak of 850 C sample
show asymmetry. But this peak can not be decomposed into the
two or more different peaks by Gauss fitting, so, the asymmetry
should not be caused by the secondary phase formation. We
attempt to explain that the asymmetry of (002) peak may be
induced by a large number of Zn1xMgxO nanowires with the small