Li Mengke

Morphology of Platinum Nanowire Array Electrodeposited Within Anodic Aluminium Oxide Template Characterized by Atomic Force Microscopy

Uniform platinum nanowires were synthesized by electrodepositing the platinum under a very low altering current frequency (20 Hz) and increasing voltage (5-15 V) in the pores of anodic aluminium oxide (AAO) template. Atomic force microscopy observation indicates that the template membranes we obtained have hexagonally close-packed nanochannels. The platinum nanowires have highly ordered arrays after partially dissolving the aluminium oxide membrane. With the increasing dissolving time, the platinum nanowire array collapsed. A concave topography of the aluminium substrate was observed after the aluminium oxide membrane was dissolved completely and the platinum nanowires were released from the template. Platinum nanowires were also characterized by transmission electron microscopy and the phase structure of the Al/AAO/Pt composite was proven by x-ray diffraction.

Selective Area Growth of GaAs in V-Grooved Trenches on Si(001) Substrates by Aspect-Ratio Trapping

A high quality of GaAs crystal growth in nanoscale V-shape trenches on Si(001) substrates is achieved by using the aspect-ratio trapping method. GaAs thin films are deposited via metal-organic chemical vapor deposition by using a two-step growth process. Threading dislocations arising from lattice mismatch are trapped by laterally confining sidewalls, and antiphase domains boundaries are completely restricted by V-groove trenches with Si {111} facets. Material quality is confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution X-ray diffraction. Low temperature photoluminescence (PL) measurement is used to analyze the thermal strain relaxation in GaAs layers. This approach shows great promise for the realization of high mobility devices or optoelectronic integrated circuits on Si substrates.

Photoluminescence Properties of Silicon Nanowires and Carbon Nanotube-Silicon Nanowire Composite Arrays

Composite arrays of multi-wall carbon nanotubes (MWNTs) and silicon nanowires (SiNWs) are fabricated by means of the chemical vapour deposition method in porous anodic aluminium oxide (AAO) templates. The results of the scanning electron microscopy, high-resolution transmission electron microscopy, and transmission electron microscopy have shown that SiNWs are successful nested or filled in the hollow cavities of synthesized MWNT arrays in AAO templates to form MWNT-SiNW composite arrays. The photoluminescence (PL) intensity degradation and a blueshift of PL peak position, usually created from the chemical instability of the SiNW surfaces, are decreased and eliminated clearly in the composite arrays. The composite arrays of MWNTs-SiNWs exhibit more enhanced intensity and stability of PL performance than the SiNW arrays deposited in AAO templates.