Laser-based imaging of individual carbon nanostructures

Laser-based imaging and characterization of individual nanostructures provides significant advantages over other imaging techniques, such as scanning probe microscopy and electron microscopy, by allowing simultaneous imaging and spectroscopic measurements. Laser-based techniques also involve simpler sample preparation, cause minimal sample damage and provide high-throughput measurements over large sample areas. In this article, we review recent progress in this field focusing on applications in the study of individual carbon nanostructures, mainly carbon nanotubes and graphene. Absorption, Rayleigh, Raman and photoluminescence techniques will be discussed for optical-based detection, and photocurrent and photothermal current techniques will be discussed for electrical detection. Each optical technique relies on a different physical process, allowing spectroscopic investigation of the fundamental optical, thermal and optoelectronic processes for individual nanoscale carbon structures. In addition, we will compare the various advantages of wide-field and focused (confocal) laser excitation/detection geometries and discuss ongoing efforts to overcome the speed and resolution limitations of laser-based imaging.