Distinguishing Field Effects from Charge Effects in the Optoelectronic Properties of Carbon Nanotube Films

Abstract

We have used charge-induced absorption to quantify the influence of injected charges on electroabsorption measurements in single-wall carbon nanotube films. The interpretations of experimental measurements of χ3 processes in nanotubes are simplified by taking into account the change in electron-electron interactions upon charge injection. Electroabsorption spectra that are properly corrected for charge-induced effects show remarkable agreement with a simple Stark shift of the exciton transitions with no notable second-derivative contributions. Thus, distinguishing electric field effects from carrier density effects allows for a more rigorous calculation of exciton polarizability from electroabsorption measurements, even in heterogeneous films. PACS: 78.67.Ch Nanotubes: optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures.