Carbon nanotube growth on piezoelectric AlN films: influence of catalyst underlayers

Abstract

Carbon nanotube (CNT) growth on piezoelectric AlN substrates has appeared to be important in sensing purposes using acoustic technology. CNT forests can act as sensing layers with high surface active area. We study such growth by using Fe as active catalyst and Ti, Cr and Al as catalyst underlayers. All underlayers enable CNT growth at temperatures ranging from 450 °C to 650 °C. Whereas Fe alone and Ti/Fe or Cr/Fe stacks provide multi-walled CNTs with high defect content, Al/Fe stack yields CNT forests with G to D peak ratios up to 9.2 with single and double-walled CNT content. The low surface energy of Al and its roughness are key factors in this successful growth. These results are not only useful for sensing applications but can also place AlN as an alternative insulating substrate for CNT growth.