ABSTRACT
The use of high quality semiconducting nanomaterials for advanced device applications has been hampered by the unavoidable variability in the growth of one-dimensional (1D) nanomaterials such as nanowires (NWs) and nanotubes, resulting in highly variable electrical properties across the population. Therefore, assessment of the quality of nanomaterials is vital for the fabrication of high-performance and reliable electronic devices. The controllable selection of high quality NWs has been recently demonstrated using a dielectrophoretic (DEP) NW assembly method; however, no convenient, rapid method has been adopted for the characterization of nanomaterial semiconducting properties. In this study, we solve this challenge with a low-cost, industrially scalable method for the rapid analysis of the electrical properties of inorganic single crystalline NWs, by identifying key features in the DEP frequency response spectrum (1 kHz - 20 MHz). NWs dispersed in anisole were characterized using a three-dimensional DEP chip (3DEP) in 60 seconds, and the resultant spectrum demonstrated a sharp change in NW response to DEP signal in 1 MHz - 20 MHz frequency rage. The 3DEP analysis, confirmed by field-effect transistor (FET) data, indicates that NWs with higher quality are collected at high DEP signal frequency range such as above 10 MHz. These results show that platforms such as the 3DEP, can be used for the characterization of rod-shaped nanoscale particles where the dipole moment is sufficiently large. It also shows that the 3DEP can be used to assess heterogeneous nanoparticle mixtures and identify nanomaterials with superior conductivity properties. The proposed methodology can be applied to any type of 1D nanomaterials. The 3DEP analysis coupled with dielectrophoretic assembly for the deposition of NWs at selected signal frequencies, leads to a reproducible fabrication of high quality NW FET devices.
