Carbon nanotube nanocontact in T-junction structures

The authors report transport measurements on naturally formed carbon nanotube T junctions with a semiconducting bar and a metallic stem. The T junctions provide a unique structure that allows them to compare the quasi-zero-dimensional (Q0D) contact formed at the junction node with the quasi-one-dimensional (Q1D) contact formed between the semiconducting bar and the lithographically defined gold. From the bias-induced barrier lowering, it shows that the Q1D contact behaves like an end-bonded contact which has extended depletion tail along the tube axis, while the Q0D case acts as a side contact which has constrained depletion perpendicular to the tube axis. (C) 2007 American Institute of Physics.