Fabrication, Device Assembly, and Application of One-Dimensional Chalcogenides Nanostructures

Nanotechnology has received a tremendous amount of research interests ever since the first discovery of carbon nanotubes. One-dimensional nanostructures, such as nanorods, nanowires, nanobelts as well as nanotubes, are of significant interest because of their potential application as interconnects and functional units in nanoscale electrical, optoelectronic, electrochemical, electromechanical, thermoelectric, spintronic, photovoltaic, and sensory devices. Nanoscale one-dimensional devices promise to deliver improved performance, to miniaturize bulky devices, to enable higher density nanoscale devices, and to lower energy consumption. As the radius of these one-dimensional nanostructures fall below the exciton Bohr radius of their respective materials, the structural morphology and size effectively modulates the fundamental electrical, optical, and magnetic properties due to quantum confinement effect. In addition, the high surface to volume ratio of one-dimensional nanostructures enables the device properties to be extremely sensitivity to the environment which is particularly attractive for sensing application.Currently, the focuses of nanotechnology research are 1) the fabrication technique with control over the composition, crystal structure, morphology, and size, 2) the device assembly of nanostructures into complex functional devices, and 3) the characterization and application of these nanoscale devices. There are a multitude of fabrication techniques for one-dimensional nanostructures, including but not exclusively, vapor-solid, vapor-liquid-solid, colloidal, solution-liquid-solid, self-assembly, and template directed electrodeposition. As one-dimensional nanostructures are produced, several techniques are available to assemble them into functional complex nanoscale devices, including but not exclusively, electron beam lithography, focus ion beam, magnetic assembly, and AC dielectrophoretic alignment.In this work, one-dimensional cadmium telluride (CdTe) nanostructures are fabricated via the template directed electrodeposition. Fundamental properties, such as composition, crystal structure, morphology, size, electrical, and optoelectronic properties, are examined. The tuning of electrical and optoelectronic properties by the modulation of various material characteristics are demonstrated for potential photodetection application. To demonstrate biosensing application of one-dimensional nanostructure, label-free DNA recognition and sensing application capable of femtomolar detection is achieved with a single bismuth telluride (Bi2Te3) nanoribbon biosensing device