Abstracts
Kenneth Fontanez
Abstract
Abstract:Detection of ionizing radiation is crucial in different fields including energy, national security, biological and nuclear research, and other applications. One of the key characteristics of SWNTs for electronic and optoelectronic applications is that their metallic or semiconductor behavior, and the conductive properties of the material, depend on the presence of defects in the structure. The presence of a defect in the nanotube walls, i.e. a single atom missing, or the incorporation or interaction with another structure, can result locally in the change of the electronic distribution and, therefore, to the variation of the conductive characteristics of nanotubes. These defects, or the interaction with structures present in the environment, can be induced by the presence of ionizing radiation. The variations of these electrical properties can be measured, and, from these results, a clear correlation can be established with the radiation dose generated by the presence of these local defects in the nanotube. In this research, vertically aligned carbon nanotubes were grown by chemical vapor deposition (CVD) on a silicon oxide substrate with alternating layers of TiN (see Figure). The CNTs where exposed to nitrogen implantation and X-ray radiation to study later the change in resistivity.