Qian, Huihong; Araujo, Paulo T.; Georgi, Carsten; Gokus, Tobias; Hartmann, Nicolai; Green, Alexander A.; Jorio, Ado; Hersam, Mark C.; Novotny, Lukas; Hartschuh, Achim
Visualizing the Local Optical Response of Semiconducting Carbon Nanotubes to DNA-Wrapping.
In: Nano Letters, Vol. 8, Nr. 9: S. 2706-2711
We studied the local optical response of semiconducting single-walled carbon nanotubes to wrapping by DNA segments using high resolution tip-enhanced near-field microscopy. Photoluminescence (PL) near-field images of single nanotubes reveal large DNA-wrapping-induced red shifts of the exciton energy that are two times higher than indicated by spatially averaging confocal microscopy. Near-field PL spectra taken along nanotubes feature two distinct PL bands resulting from DNA-wrapped and unwrapped nanotube segments. The transition between the two energy levels occurs on a length scale smaller than our spatial resolution of about 15 nm.