Distinguishing self-gated rectification action from ordinary diode rectification in back-gated carbon nanotube devices

Self-gating leading to rectification action is frequently observed in two-terminal devices built from individual or networked single-walled carbon nanotubes (SWCNTs) on oxidized Si substrates. The current-voltage (I-V) curves of these SWCNT devices remain unaltered when switching the measurement probes. For ordinary diodes, the I-V curves are symmetric about the origin of the coordinates when exchanging the probes. Numerical simulations suggest that the self-gated rectification action should result from the floating semiconducting substrate which acts as a back gate. Self-gating effect is clearly not unique for SWCNT devices. As expected, it is absent for devices fabricated on insulating substrates. (C) 2008 American Institute of Physics.