Figure 4From: Enhanced field electron emission properties of hierarchically structured MWCNT-based cold cathodesThreshold field dependence on the aspect ratio of the Si pyramids. TF values obtained from the flat silicon substrate (AR = 0) from the present work as well as from literature are also included. The inset shows the SEM images of the MWCNT-coated Si pyramids for different AR values (the white scale bar is 2 μm).Back to article page