To study the crystal structure, phase, and orientation
of the ZnO nanorods, XRD patterns of the ZnO
nanorods grown on the Si (100) and sapphire (0001)
substrates at 700◦C with different oxygen flow were
recorded and are shown in Fig. 6. For all the samples,
a stronger peak of ZnO corresponding to (0002) plane is observed along with its higher order peak of
(0004) plane .