(Invited) Carbon Nanotube Based Photonics

Abstract

The use of optics in microelectronic circuits to overcome the limitation of metallic interconnects is more and more considered as a viable solution. Numerous photonic building blocks, compatible with CMOS technology, have been developed. However, integration of all these building blocks on the same chip is a bottleneck, due to the various materials used (Ge, Si, III-V). This drawback could be significantly overcome by considering carbon nanotubes, which have the ability to emit, modulate and detect light in the wavelength range of silicon transparency. That makes them a promising candidate and in consequence an alternative material for active device in silicon photonics technology.Few years ago, we have developed an efficient method to extract semiconducting nanotube (s-SWNT), using a polyfluorene agent in toluene followed by ultracentrifugation steps [1]. We demonstrated that this method allows obtaining metallic-free s-SWNT samples, as confirmed by photoluminescence, absorption and Raman spectroscopy, and the realisation of high Ion/Ioff FET devices.This achievements leads to the first experimental demonstration of a strong optical gain of 160 cm-1 at a wavelength of 1.3 µm in (8,7) s-SWNT at room temperature [2]. A special emphasis will be put on the s-SWNT extraction, as optical gain could not be achieved in a raw or lowly extracted sample.Carbon nanotube properties were then relied on the existing silicon photonic platform, and we envision the use of carbon nanotubes as active optoelectronic devices in silicon. A complete study of the coupling between carbon nanotubes and silicon waveguides was performed [3]. In particular, temperature independent emission up to 100°C from carbon nanotubes in silicon was demonstrated, which opens bright perspectives for future high performance integrated circuits(Figure : Integration scheme of carbon nanotube with silicon waveguide, showing carbon nanotube emission throught the waveguide)[1] N. Izard, S. Kazaoui, K. Hata, T. Okazaki, T. Saito, S. Iijima and N. Minami, Appl. Phys. Lett., 92, 243112 (2008)[2] E. Gaufrès, N. Izard, X. Le Roux, D. Marris-Morini, S. Kazaoui, E. Cassan and L. Vivien, Appl. Phys. Lett., 96, 231105 (2010)[3] E. Gaufrès, N. Izard, A. Noury, X. Le Roux, G. Rasigade, A. Beck and L. Vivien, ACS Nano, 6, 3813 (2012)