Electronic‐Band‐Structure Mapping of Nanotube Transistors by Scanning Photocurrent Microscopy

Carbon-nanotube field-effect transistors are characterised using scanning photocurrent microscopy. The photocurrent response (see image), reflecting the strength of the local built-in electric field, depends on the applied source–drain bias and the charge-transport regime adjusted by the back-gate voltage. Such measurements enable the extraction of electronic band-structure profiles corresponding to the different operation conditions.