Influence of various contact interfaces between carbon nanotubes and Si substrate on field emission properties

Thin nano porous alumina films were grown on n-type Si wafers by anodizing sputtered-deposited Al and Al/Ti layers to prepare three types of contact interface- CNT/TiO2/Ti/n-Si, CNT/SiO2/n-Si, and CNT/Ni/n-Si -- for later synthesis of carbon nanotubes (CNTs) in the alumina pores. CNTs were grown by CVD in the presence of ferrocene catalyst. Measurements of field emission properties of the CNTs with the different contact interfaces were performed in the direct and pulse current modes. The onset voltage and the field enhancement factor b were calculated for each interface type. The differences in the field emission behavior and the emission mechanism have been discussed. (authors)