Structural and Electrical Characteristics of Carbon Nanotubes Formed on Silicon Carbide Substrates by Surface Decomposition
Aligned carbon nanotubes (CNT’s) are formed on the surface of silicon carbide (SiC) wafers during high temperature anneals. The exposed 4H SiC surface transforms into CNT’s for temperatures in the range of 1400-1700°C and under moderate vacuum conditions (10-2 – 10-5 torr). The rate of formation on the C-face (0001,‾) is about three times the rate on the Si-face (0001), but both rates increase with anneal temperature. SEM, TEM and Raman scattering measurements have confirmed the presence of both single-wall and multi-wall CNT’s. The carbon source is believed to be residual carbon from the SiC left on the surface after preferential evaporation of Si. CNT formation is believed to be catalyzed by low concentrations of residual oxygen in the chamber. Subsequent I-V measurements provide insight into the electrical characteristics of the CNT’s and the SiC/CNT interface.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
J. Boeckl et al., "Structural and Electrical Characteristics of Carbon Nanotubes Formed on Silicon Carbide Substrates by Surface Decomposition", Materials Science Forum, Vols. 527-529, pp. 1579-1582, 2006