Synthesis of Carbon Nanotubes in MW Plasma Torch with Different Methods of Catalyst Layer Preparation and their Applications

The microwave plasma torch (2.45 GHz) was used for the synthesis of carbon nanotubes from the mixture of CH4/H2/Ar or C2H2/H2/Ar on different substrates with iron catalyst. Iron catalyst was prepared by vacuum evaporation of iron on Si, Si/SiOx or Si/AlxOy substrates or by deposition of iron oxide nanoparticles on Si/SiOx substrate by decomposion of Fe(CO)5 in gas feed. Such prepared substrates were used for growth of carbon nanotubes. Recostruction of the iron catalyst layer into nanoparticles was also studied in dependence on substrate buffer layer, gas atmosphere and temperature. Samples were studied by scanning and transmission electron microscopy and Raman spectroscopy. Synthesis resulted in rapid growth of MWNTs on all samples but the density, purity and nanotube diameter distribution varied. Such prepared carbon nanotube layers were used for sensing applications.Mikrovlnný plazmový hořák (2,45 GHz) byl použit pro syntézu uhlíkových nanotrubek ze směsi CH4/H2/Ar nebo C2H2/H2/Ar na různých substrátech s železnými katalyzátori. Železný katalyzátor byl připraven vakuovým odpařováním železa na Si, Si/SiOx nebo Si/AlxOy substráty nebo ukládáním nanočástic oxidu železitého Fe (CO) 5 z plynné fáze na Si/SiOx substrát. Takto připravené substráty byly použity pro růst uhlíkových nanotrubek. Vytváření vrstvy katalyzátoru na nanočástice železa byl také studován v závislosti na mezivrstvě , atmosféře a teplotě. Vzorky byly studovány skenovací a transmisní elektronovou mikroskopi a Ramanovskou spektroskopii.The microwave plasma torch (2.45 GHz) was used for the synthesis of carbon nanotubes from the mixture of CH4/H2/Ar or C2H2/H2/Ar on different substrates with iron catalyst. Iron catalyst was prepared by vacuum evaporation of iron on Si, Si/SiOx or Si/AlxOy substrates or by deposition of iron oxide nanoparticles on Si/SiOx substrate by decomposion of Fe(CO)5 in gas feed. Such prepared substrates were used for growth of carbon nanotubes. Recostruction of the iron catalyst layer into nanoparticles was also studied in dependence on substrate buffer layer, gas atmosphere and temperature. Samples were studied by scanning and transmission electron microscopy and Raman spectroscopy. Synthesis resulted in rapid growth of MWNTs on all samples but the density, purity and nanotube diameter distribution varied. Such prepared carbon nanotube layers were used for sensing applications