Different film thicknesses of polycrystalline TiO 2 thin films deposited on various unheated substrates using radio frequency (RF) magnetron sputtering is investigated. The crystalline structure, optical properties, and surface morphology and roughness were measured using an X-ray diffractometer (XRD), a field-emission scanning electron microscope (FESEM), an atomic force microscope (AFM), and a UV-Vis spectrophotometer. Polycrystalline phases were formed on unheated substrates due to the plasma particle bombardment. Crystalline structures more easily formed on the glass substrate and only nanocrystalline structures formed on the ITO glass substrate due to the surface roughness of substrates. The absorption edge and optical band gap depended on the crystalline particle size and phase structure. The XRD results indicate that 500-nm-thick film on a glass substrate had the strongest intensities of mixed anatase and rutile phases.

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A dielectrophoretic (DEP) chip with an SU-8 microcavity array for trapping single particle/cell is designed, fabricated, and quantitatively examined by simulations and experiments. The particles can be easily trapped in or pulled out of the microcavity based on negative or positive DEP force, respectively. The nonuniform electric field is formed in relation to the configuration of the microcavity array, i.e. its diameter and spacing, as described in the simulation results. In order to investigate the effects of the microcavity, two maximal flow rates for trapping particles in the microcavity and washing them away from the microcavity under different DEP voltages are determined by experiments. As the experimental results show, the extrastationary effects, provided as a particle is trapped in the microcavity, mean that the trapped particle can sustain a low flow rate even without applying DEP voltage. Consequently, this DEP chip is suitable for long-term monitoring of trapped cells by supplying the subsisting buffer at a low flow rate without the damage or heating effect caused by DEP voltage.

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A new approach for developing highly sensitive MOS photodetector based on the assistance of anodic aluminum oxide (AAO) membrane is proposed, fabricated, and characterized. It enables the photodetector with the tunability of not only the intensity but also the range of the response. Under a forward bias, the response of the MOS photodetector with AAO membrane covers the visible as well as infrared spectrum; however, under a reverse bias, the near-infrared light around Si band edge dominates the photoresponse. Unlike general MOS photodetectors which only work under a reverse bias, our MOS photodetectors can work even under a forward bias, and the responsivity at the optical communication wavelength of 850nm can reach up to 0.24 A/W with an external quantum efficiency (EQE) of 35%. Moreover, the response shows a large enhancement factor of 10 times at 1050 nm under a reverse bias of 0.5V comparing with the device without AAO membrane. The underlying mechanism for the novel properties of the newly designed device has been proposed.