EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Si-based multiwavelength light sources are of great interest for applications in photonics and multiplexed signal communication. The realization of an innovative hybrid light source operating at room temperature, obtained by embedding a carbon nanotube (CNT) dispersion inside a Si nanowire (NW) array is reported. Ultrathin Si nanowires (NWs) synthesized by metal-assisted chemical wet etching using a very thin discontinuous Au layer as precursor was used as a platform and coated with unbundled single-walled carbon nanotube (CNT) dispersions. A bright room temperature emission in the visible range due to electron-hole recombination in quantum-confined Si NWs is reported. The hybrid Si NW/CNT system exhibits a room temperature simultaneous emission both in the visible (due to Si NWs) and the IR (due to CNTs) ranges, thus demonstrating the realization of a low-cost material with promising perspectives for applications in Si-based photonics. The detailed study of the optical properties of the hybrid system evidences that the ratio between the intensity of the visible and the IR emissions can be varied within a wide range by changing the excitation wavelength or the CNT concentration and the conditions leading to the prevalence of one signal with respect to the other were investigated. The multiplicity of emission spectra obtainable from this composite material opens new perspectives for Si nanostructures as an active medium in light sources for Si photonics applications.