03. Large anisotropy of electrical properties in layer-structured In2Se3 nanowires

Layer-structured indium selenide (In2Se3) nanowires (NWs) have large anisotropy in both shape and bonding. In2Se3 NWs show two types of growth directions: [11−20] along the layers and [0001] perpendicular to the layers. We have developed a powerful technique combining high-resolution transmission electron microscopy (HRTEM) investigation with single NW electrical transport measurement, which allows us to correlate directly the electrical properties and structure of the same individual NWs. The NW devices were made directly on a 50 nm thick SiNx membrane TEM window for electrical measurements and HRTEM study. NWs with the [11−20] growth direction exhibit metallic behavior while the NWs grown along the [0001] direction show n-type semiconductive behavior. Excitingly, the conductivity anisotropy reaches 103−106 at room temperature, which is 1−3 orders magnitude higher than the bulk ratio.