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 singlewall carbon nanotube films. The interpretations of experimental measurements of (3) 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.