Approach curve method for large anode-cathode distances

An important technique used to characterize field emission is the measurement of the emitted current against electric field (I X E). In this work we discuss a procedure for obtaining I X E data based on multiple approach curves. We show that the simulated features obtained for an idealized uniform surface matches available experimental data for small anode-cathode distances, while for large distances the simulation predicts a departure from the linear regime. We also discuss the shape of the approach curves for large anode-cathode distances for a cathode made of carbon nanotubes. (C) 2004 American Vacuum Society.