Carbon-nanotube-based hybrid materials: nanopeapods

This review article focuses on the structures and properties of novel hybrid nanocarbon materials, which are created by incorporating atoms and molecules into the hollow spaces of carbon nanotubes (CNTs); thus they are called nanopeapods. After dealing with synthesis procedures, we discuss the structures and electronic properties of the hybrid materials based on high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), X-ray and electron diffraction, scanning tunneling microscopy (STM), and field-effect transistor transport measurements. Utilization of the low-dimensional nanosized spaces of CNTs to produce novel low-dimensional nanocluster, nanowire, and nanotube materials is also discussed.