Linear and non-linear optical properties of filled single-wall carbon nanotubes

Abstract

A new approach for modification of optical and electronic properties of single-wall carbon nanotube films via a gas phase filling of nanotubes with the stranger acceptor molecules (iodine, CuCI) is presented. The modified films are characterized by techniques of linear (UV-vis-NIR optical absorption and Raman scattering) and non-linear (pump-probe) optical spectroscopy. Keywords-single-wall carbon nanotubes; iodine; CuCI; Raman scattering; UV-vis-NIR optical absorption; pump-probe The optical spectroscopy is a sensitive instrwnent for monitoring the electronic properties of single-wall carbon nanotubes (SWNTs). In this work a new approach is proposed for triggering the conducting properties of nanotubes (from semiconducting to metallic type). This is an introduction of different molecules (acceptors of electrons) into the nanotube inner space from a gas phase. New molecules form different structures (from monoand multichains [1] to one­ dimensional crystals) depending on the diameter and geometry of host nanotube (Fig. 1). As a result, the electrons move toward these new inner structures, and the Fermi level of a host nanotube is shifted into the valence band. This should decrease Fig. I. A High Resolution Transmission Electron Microscopy (HRTEM) image ofSWNTs (with an average diameter of 2.2 nm) filled with CuCI. formed inside nanotubes one-dimensional crvstals. K. Kaunisto Technical University of Tampere, Tampere, Finland A.G. Nasibulin, E.1. Kauppinen Aalto University, Espoo, Finland A.L.Chuvilin CIC nanoGUNE Consolider, San Sebastian. Spain 0.16,---------------,