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DS: Fachverband Dünne Schichten

DS 35: Poster I: Application of thin films; Focus session: Sensoric micro and nano-systems; Focus Session: Sustainable photovoltaics with earth abundant materials; Graphen (joint session with TT; MA; HL; DY; O); Ion and electron beam induced processes; Layer properties: electrical, optical, and mechanical properties; Magnetic/organic interfaces, spins in organics and molecular magnetism; Micro- and nanopatterning (jointly with O); Organic electronics and photovoltaics (jointly with CPP, HL, O); Thermoelectric materials

DS 35.19: Poster

Mittwoch, 2. April 2014, 17:00–20:00, P1

Laser induced changes in single-walled carbon nanotubes — •Jana Kalbacova, Raul D. Rodriguez, Honeyeh Matbaechi, and Dietrich R.T. Zahn — Semiconductor Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany

Carbon nanotubes (CNTs) are one of the materials of future technologies and already today they are finding their way into applications, such as in field effect transistors and photovoltaics. However, for the performance of the device, it is crucial to keep the ratio of metallic to semiconducting at minimum. To monitor this ratio, it is beneficial to use Raman spectroscopy where the so-called radial breathing mode (RBM) of CNTs is observed [1].

It was also shown that in order to induce defects in CNTs, high power laser can be employed. On the other hand, laser illumination was also proposed to eliminate carbonaceous contaminations without CNT destruction [1]. Thus predictably, with optimized laser power we can achieve changes within carbon nanotubes without their destruction. In this contribution, we show how optimized laser power can lead to changes in carbon nanotubes, while preserving the CNT integrity. Changes are observed mostly in the radial breathing mode region. We attribute these to the selective elimination of CNTs with certain chiralities. Simultaneously, by using spatially resolved Raman spectroscopy mapping, we show that the defective region is larger than expected, extending beyond the laser-illuminated spot. We will discuss the changes in the Raman spectra that originate from such defect gradient.