Exciton dissociation and stark effect in the carbon nanotube photocurrent spectrum.

Mohite, Aditya D; Gopinath, Prasanth; Shah, Hemant M; Alphenaar, Bruce W · Nano Lett · 2008

basic_science · Level V

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Abstract

The field-dependent photocurrent spectrum of individual carbon nanotubes is measured using a displacement photocurrent technique. A series of peaks is observed in the photocurrent corresponding to both excitonic and free carrier transitions. The photocurrent peak corresponding to the ground state exciton increases by a factor of 200 beyond a critical electric field, and shows both red and blue shifts depending on the field regime. This provides evidence for field-induced mixing between excitonic and free carrier states.