Preparation and characterization of ZnO microcantilever for nanoactuation

Zinc oxide [ZnO] thin films are deposited using a radiofrequency magnetron sputtering method under room temperature. Its crystalline quality, surface morphology, and composition purity are characterized by X-ray diffraction [XRD], atomic force microscopy [AFM], field-emission scanning electron microscopy [FE-SEM], and energy-dispersive X-ray spectroscopy [EDS]. XRD pattern of the ZnO thin film shows that it has a high c-axis-preferring orientation, which is confirmed by a FE-SEM cross-sectional image of the film. The EDS analysis indicates that only Zn and O elements are contained in the ZnO film. The AFM image shows that the film's surface is very smooth and dense, and the surface roughness is 5.899 nm. The microcantilever (Au/Ti/ZnO/Au/Ti/SiO2/Si) based on the ZnO thin film is fabricated by micromachining techniques. The dynamic characterizations of the cantilever using a laser Doppler vibrometer show that the amplitude of the cantilever tip is linear with the driving voltage, and the amplitude of this microcantilever's tip increased from 2.1 to 13.6 nm when the driving voltage increased from 0.05 to 0.3 Vrms. The calculated transverse piezoelectric constant d31 of the ZnO thin film is -3.27 pC/N. This d31 is high compared with other published results. This ZnO thin film will be used in smart slider in hard disk drives to do nanoactuation in the future

Preparation of ordered TiO2 macroporous membrane using PBMA colloid crystal as template

Poly(butyl methacrylate) (PBMA) colloidal crystal templates were assembled orderly on the clean substrates of monocrystalline silicon by dip-drawing technique and titanium dioxide (TiO2) macroporous membranes were prepared by using sol-dipping template method to fill the interstices among the PBMA templates, followed by calcination to remove the templates at 550℃. Calcination of the PBMA templates was carried out according to the following procedure: the rate of rising temperature was 5℃/min from room temperature to 150℃, 2℃/min from 150℃ to 270℃, 1℃ /min from 270℃ to 430℃, 2℃/min from 430℃ to 550℃ and maintained it at 550℃ for 2h. X-ray diffraction (XRD) spectra indicated the macroporous materials were anatase structure. The polymerization mechanism of BMA with Fenton reagent as a new initiator was discussed, and the removal process of the PBMA templates and the formation of TiO2 pore size were investigated, respectively. The results showed that the new method of polymerization overcomes many problems associated with the conventional emulsion polymerization techniques such as long reaction time, necessary deoxygenation, and complicated operation