[摘要]：We investigate dielectrophoretic deposition of single-walled carbon nanotubes using an in situ detection system. Pairs of electrodes are stimulated with a small-amplitude, low-frequency voltage superimposed on a large-amplitude, high-frequency dielectrophoretic voltage. Measuring the magnitude of the current both at dc (I-dc) and at the low frequency (I-ac) through a digital lock-in technique allows us to determine when a nanotube has made electrical contact and to halt the dielectrophoretic process. Because I-dc is determined by nonlinearities in the device current-voltage characteristic, measurement of the I-dc/I-ac ratio allows the real-time determination of whether the deposited nanotube is metallic or semiconducting.
