Researchers at NIST and Arizona State University have made significant advancements in controlling the synthesis of carbon nanotubes using an environmental scanning transmission electron microscope (ESTEM). The team used ESTEM to visualize and control the placement of iron nanoparticles on a silicon oxide substrate. They found that various factors influence the size and catalytic activity of these nanoparticles, including the choice of catalyst precursor, substrate temperature, deposition time, and electron beam energy.
By utilizing real-time visualization provided by the ESTEM, the researchers were able to optimize iron nanoparticle size and positioning, control carbon co-deposition, and manage catalyst particle chemical inactivity due to graphitic shells. Their findings indicate that the diiron nonacarbonyl precursor is better suited for controlled carbon nanotube growth at higher substrate temperatures. The results are expected to aid in the creation of carbon nanotube substrates for use in low-cost field emission displays (FEDs).
Keywords: Carbon nanotubes, Environmental scanning transmission electron microscopy, Nanoparticle control
