3. Results and discussion
3.1. Crystallinity and crystallite size analysis using XRD data
The crystal structure and phase purity of the samples were
investigated using powder XRD. The powder X-ray diffraction
study was performed using X’Pert diffractometer withKaradiation of wavelength 1.5406
˚ A. A beam voltage of 40 KV and a 30 mA
beam current were used. The data were recorded at a continuous
scan rate of 0.31/min and the phase was identified with JCPDS
database.Fig. 1represents the XRD patterns of synthesized ZnO.
All difractograms show the nine prominent peaks (indexed with
JCPDS 36-1451) which are narrowed and highly intense. This
reveals that the formed products have good crystallinity. The peak
intensity of the (1 0 1) reflection for the as-prepared ZnO samples
decreases in the order A34A24A1 and hence the crystallinity of
the samples also deter in the same order. From the peak intensities, it is also inferred that the growth velocity of the nano rods
formed at pH 9 is very high compared to those formed at pH of 11
and 13 which is confirmed by the length of the rods obtained from
SEM images. The average crystallite sizes of the as-prepared
samples were determined using Debye Scherer’s formula (Eq. 1).
For the crystallite size analysis, the highly intense and sharp
diffraction peak at 2y¼36.31corresponds to the (1 0 1) diffraction
of the ZnO hexagonal wurtzite phase is employed.
/DS¼0:9l=bcosy ð1Þ
where/DSis the average crystallite size, lis the CuKaradiation
wavelength, 1.5406˚
A,bis the full width at half maximum in
radians and y is the scattering angle in degree. The average
crystallites of A1, A2 and A3 are listed inTable 1.