November, 2022, Vol.31 No 6

Figure shows the SEM images of the ZnO tetrapods synthesized at different plasma powers (500 and 1200 W) and with different collection sites (A and B). The A and B imply the collection sites at distances of 0 ~ 10 and 30 ~ 40 cm, respectively, from the Zn inlet region. It is found that the sizes of the 500A samples are smaller than that of the 500B samples. This means that the regions farther from the plasma plume have longer growth times than the regions closer to the plume, for the same plasma power. On comparing 500 and 1200 A, it is found that the sizes of the tetrapods increase with increasing plasma power, within the same region. This is natural, because higher applied power yields higher plasma temperature and a higher number of active species in the plasma, enhancing the growth environment.