**4.2 Preparation of slides**

Slides were divided equally so as to make it fit for the size required for XRD test. After that slides are washed properly with distilled water and dried. Those slides were dipped into a beaker containing the solution of concentrated Nitric acid (conc. HNO3) at an angle of 45°. After few hours slides were taken out and were again dried and are also covered by paper so as to avoid the accumulation of dust particles on the slides. Using dropper, few drops of the solution of ZnO is then dropped over

**Figure 4.** *Preparation of slides.*

all the slides at the center properly in such a way that solution remains stagnant as shown in the **Figure 4**. Again this slides are kept covered for few days for drying.
