ABSTRACT
1-D nanostructures of metal oxide such as nanowires, nanorods, and nanotubes have been investigated for applications in different sensors. Their unique properties, geometry, and microstructure have made them suitable for sensing applications. Some of the important properties of 1-D nanostructures include high surface-to-volume ratio, tunable bandgap, high stability, and multifunctionality. From the fundamental viewpoints, 1-D nanostructures have unique properties because the electronic transport phenomenon is governed by the Debye radius throughout the 1-D nanostructure. There are many techniques that can be used to fabricate these nanostructures with a single metal oxide or mixture of different oxides. The common fabrication techniques are the chemical vapor deposition (CVD), physical vapor deposition (PVD), hydrothermal synthesis, electrochemical deposition and etching and vapor phase deposition. Devices have been designed to utilize physical, electronic and chemical properties of these 1-D nanostructures. Among them, the change of resistance, field-effect properties, photoconductivity, photoluminescence and electrochemical activity of metal oxides have attracted much attention. This chapter discusses different types of 1-D metal oxides used in sensors, their fabrication techniques, and physical and chemical properties related to various sensors. The first section of the chapter is devoted to the introduction of 1-D metal oxides, and the subsequent sections discuss their applications in biosensors, ultraviolet (UV) light sensors, humidity sensors and gas sensors. A number of 1-D semiconducting metal-oxides such as ZnO, SnO2, In2O3, and TiO2 are covered, and their electrical, mechanical and sensing properties are discussed. This study gives comprehensive knowledge about different 1-D metal oxide sensors with their working mechanisms, physical properties, surface morphology, and sensing properties.
