Xiaoye Jing

Heterogeneous Graphene Nanostructures: ZnO Nanostructures Grown on Large‐Area Graphene Layers

In this work, the synthesis and characterization of three-dimensional hetergeneous graphene nanostructures (HGN) comprising continuous large-area graphene layers and ZnO nanostructures, fabricated via chemical vapor deposition, are reported. Characterization of large-area HGN demonstrates that it consists of 1-5 layers of graphene, and exhibits high optical transmittance and enhanced electrical conductivity. Electron microscopy investigation of the three-dimensional heterostructures shows that the morphology of ZnO nanostructures is highly dependent on the growth temperature. It is observed that ordered crystalline ZnO nanostructures are preferably grown along the <0001> direction. Ultraviolet spectroscopy and photoluminescence spectroscopy indicates that the CVD-grown HGN layers has excellent optical properties. A combination of electrical and optical properties of graphene and ZnO building blocks in ZnO-based HGN provides unique characteristics for opportunities in future optoelectronic devices.

Microtubule‐Based Gold Nanowires and Nanowire Arrays

Biological structures are attractive as templates to form nanoscale architectures for electronics because of their dimensions and the ability to interact with inorganic materials. In this study, we report the fabrication and electrical properties of microtubule (MT)-templated Au nanowires, and methods for assembling Au nanowire arrays based on these templates. The adsorption of MTs on silicon substrates is an effective means for preserving the conformation of the MT and provides a convenient platform for electrical measurements. To improve the metallization of MTs, a photochemical route for gold reduction is adapted, which leads to continuous coverage. The conductivity values measured on micrometer-long nanowires are similar to those reported for other biotemplated gold nanowires. A protocol for fabricating arrays of MT-templated gold nanowires is demonstrated.

InSb nanowire based field effect transistor

InSb nanowire field effect transistors (NWFET) were fabricated using electrochemically synthesized nanowires. To accurately extract transistor parameters, we introduced a model which takes into account the often ignored ungated nanowire segments. A significant improvement in extracted device parameters was observed which demonstrated that conventional models tend to underestimate the gate effect and therefore lead to lower carrier mobilities. Based on the model, we obtained a NWFET ON current of 11.8uA, an ION/IOFF ratio of 63.5 and hole mobility of 292.84 cm2V-1s-1.

Temperature dependent transport in nanotube bioconjugates

Carbon nanotube (CNT) based bioconjugates are among the candidates for molecular level electronics. In this work, we have studied transport mechanism of single walled carbon nanotube (SWNT) - peptide nucleic acid (PNA) bioconjugates. Electrical conductivity of the bioconjugates was studied at temperatures ranging from 70 K to 350 K. Negative differential resistance (NDR) behavior was observed at almost all temperatures and conductivity was found to increase with increasing temperatures. NDR behavior can be attributed to alignment and misalignment of energy bands of SWNT and PNA under different voltages.