| Quasi-one-dimensional (Q1D) nanostructures such as nanotubes and nanowires have been widely regarded as the potential building blocks for nanoscale electronic, optoelectronic and sensing devices. In our work, several types of semiconducting nanowires, including zinc oxide (ZnO) nanowires, gallium oxide (Ga2O 3) nanowires, etc, have been successfully synthesized with chemical vapor deposition method. The crystal structures of the as grown nanostructures were characterized by electron microscopies which revealed their high crystallinity. Along with other Q1D nanostructures, such as silver-tetracyanoquinodimethane (Ag-TCNQ) nanowires and iron oxide (Fe2O3) nanobelts, they were fabricated into field-effect transistors, photodetectors, electrical switching device with memory effect and chemical sensors with techniques including electron beam lithography, photolithography and focus ion beam. The physical properties studies were carried out with these devices. The electrical transport studies revealed the carrier concentration and field-effect mobility of the nanowire transistors. Photoconduction studies were performed on individual nanowires, these nanowires only functioned as optically gated transistors, but also demonstrated polarization dependent photodetection behavior originated from their quasi-one-dimensional nature. Due to the small diameter and controllable electron concentration, semiconducting nanowire transistors were implemented as highly sensitive chemical sensors with ability to detect various toxic gases.; To fully utilize the scaling advantage of the Q1D structures, we developed a series of process to fabricate high density ZnO nanowire arrays inside dielectric templates. The electrical transport and photoconduction property of the individual nanowires in arrays were characterized with conductive scanning probe microscopy. Finally, the designs of vertical nanowire transistors based on such high density nanowire array will be demonstrated. These works pave the way of using semiconducting nanowires for integrated nanoelectronics and photonics. |
