However, although the perpendicular coercivity (Hc⊥) of [Co/Ni]N can be increased by tuning the structural parameters such as the repetition number N, or the layer thicknesses of seed layer and magnetic sublayers, the enhancement is very limited.
We suggest that one of the important reasons for the alignment variation according to different thickness of the seed layers is the ZnO seed roughness, which is also reported by previous research[19, 21].
Figure 1b shows that the substrate transmittance gradually decreases as the thickness of the seed layer increases, indicating that the seed layer should be as thin as possible in order to minimize both the parasitic absorption and reflection.
As a rule of thumb, the gap between each seed should be the same size as the thickness of the seed you are sowing.
We demonstrate that the growth of the ZnO NWs on ultra-thin seed layers is strongly influenced by the substrates and thickness of the seed films.
However, it is reported that the roughness and size distribution vary with the thickness of the seed layer [23], so hydrothermal growths of ZnO nanorods on RF-sputtered seed layers with different thicknesses are performed.
The thickness of the seed layer is about 20 nm.
However, the reported thickness of the seed layers prepared by ALD was greater than 10 nm[19, 20].
The thickness of the seed coat was measured under a digital microscope.
Thus, an indication is that the fundamental limitation thickness of Si seed layer can be reduced to 5 Å.
