Length-Dependent Dielectric Polarization in Metallic Single-Walled Carbon Nanotubes

A major driving force behind the research of SWNT electronic properties is their potential in nanoelectronic applications. It has been predicted and experimentally verified that the electronic properties of metallic and semiconducting SWNTs are dependent on their diameter and chirality. With the increase ill the density of integration, the length of SWNTs used in electronic devices is approaching submicrometer and nanometer scales. It is thus necessary to understand how the length affects the properties of SWNTs besides chirality and diameter. Here, we report that the dielectric response of metallic SWNTs decreases with length. Experimental investigation and numerical modeling determine that the apparent decrease in longitudinal dielectric polarization is due to higher defect density in shorter nanotubes.