Since the CNTs grow only on the treated stainless steel surfaces,
by preventing some areas of the stainless steel surfaces from
etching we obtained selective growth of CNTs on patterned
stainless steel substrates. Figure 3a shows a stainless steel substrate
patterned with photoresist by conventional microfabrication
technique. The characters “NMDL” on the substrate are exposed
to the acid while the remaining area is protected by the photoresist.
After the acid treatment, the substrate was cleaned thoroughly
with acetone to remove all the photoresist and was placed in the
CVD furnace for CNT growth. An SEM image of the top view
of the sample after the CNT growth can be seen in Figure 3b.
It is clear from this figure that the CNTs are present only on the
characters NMDL and not on the remaining places that were
covered with photoresist.