Yuting Wan

Behind the change of the photoluminescence property of metal-coated ZnO nanowire arrays

The effect of metal coating on the photoluminescence (PL) properties of ZnO nanowire arrays has been investigated in detail in this letter. The Zn coating induces remarkable enhancement of the ultraviolet and green emissions of the nanowires, while the deposition of Ag leads to notable decrement of them. A model considering the type of contacts formed between metals and ZnO is proposed to interpret the change of the PL spectra. Also, this model is strongly supported by the PL variation of the nanowires after coating with other kinds of metals.

Nanodevices Based on Silicon Nanowires

Silicon nanowires (SiNWs) have been demonstrated as one of the promising building blocks for future nanodevices such as field effect transistors, solar cells, sensors and lithium battery; much progress has been made in this field during last decades. In this review paper, the synthesis and physical properties of SiNWs are introduced briefly. Significant advances of SiNWs-related nanodevices reported in recent literature and registered patents are reviewed. The latest development and prospects of SiNWs-related nanodevices are also discussed.

Crystal growth of Si nanowires and formation of longitudinal planar defects

Si nanowires were fabricated using Au nanoparticles as catalyst, either templated by porous anodic aluminium oxide films or on a smooth substrate of Si(100). The growth orientation of the nanowires and longitudinal planar defects such as twin defects and stacking faults were investigated using HRTEM. It was proposed that the nanowire growth was thermodynamically controlled with a slow growth rate and the growth orientation was normally the [111] zone axis of the cubic Si. When the growth rate was fast, the nanowire growth was kinetically controlled, leading to a growth orientation along the [112] zone axis. The formation mechanisms of various defects, such as twin defects, stacking faults and antiphase boundaries, are discussed.

Influence of ambient gas on the growth kinetics of Si nanocones

Multi-segment silicon nanocones were designed and fabricated to investigate their growth kinetics. We found the ambient gas influenced the growth rates of Si nanocones remarkably. The axial growth rate increased with the total pressure of ambient gas, finally approaching saturation. Meanwhile the radial growth rate also increased with the total pressure but decreased with hydrogen content. A model was developed to study the growth kinetics by combining the effects of Langmuir adsorption, silane decomposition, and hydrogen coverage on the surface of SiNCs, which agreed with the experimental results. This paper also demonstrated the controllable cone angles by the ambient gas.