Oxide Nanocomposite Thin Films Research Articles

CO 2 sensing properties of semiconducting copper oxide and spinel ferrite nanocomposite thin film

A new active layer for CO 2 sensing based on semiconducting CuO–Cu x Fe 3− x O 4 (with 0 ≤ x ≤ 1) nanocomposite was prepared by radiofrequency sputtering from a delafossite CuFeO 2 target using a specific in situ reduction method followed by post annealing treatment in air. The tenorite–spinel ferrite nanocomposite layer was deposited on a simplified test device and the response in a carbon dioxide atmosphere was measured by varying the concentration up to 5000 ppm, at different working temperatures (130–475 °C) and frequencies (0.5–250 kHz). The results showed a high response of 50% ( R air / R C O 2 = 1.9 ) at 250 °C and 700 Hz for a CO 2 concentration of 5000 ppm.

Inorganic Photo-sensitized Transparent Conductive Oxide (TCO) Nanocomposite Thin Films for Photovoltaic (PV) Energy Conversion

AbstractNanophase semiconductor composites are widely researched for the development of third-generation photovoltaic (PV) devices. Through quantum-size effects and phase assembly manipulation the optical absorption and carrier transport properties of nanocomposite films can be influenced. We investigate the potential for improved PV-relevant material performance by examining the photo-sensitization of indium-tin-oxide (ITO) with nanophase germanium (Ge). Nanocomposite films are produced by a sequential, RF-magnetron sputter deposition technique. Deposition control and post-deposition annealing are used to demonstrate the manipulation of the extended-assembly of the nanocrystalline Ge phase. Optical absorption characteristics were correlated to variations in the composite film structure as confirmed by transmission electron microscopy. In addition to structure-dependent variation in spectral absorption, spectrally resolved photoconductivity measurements demonstrate enhanced photoconductivity of composite films associated with the incorporation of the Ge phase into the ITO host. These results support the further evaluation of such nanocomposite TCO materials in optoelectronic devices, including PV systems.

Fabrication and Gas Sensitivity Study of Polypyrrole/Titanium Oxide Composite Thin Films

Polypyrrole/Titanium Oxide (PPy/TiO2) nanocomposite thin films prepared by in situ chemical oxidation polymerization and electrostatic self-assembly combined technique were investigated. The films were characterized with UV-Vis spectroscope and atomic force microscope. With the assistance of interdigitated electrodes, gas sensors using PPy/TiO2 nanocomposite thin films were achieved. The sensitivities of sensors to toxic gases NH3 and CO at room temperature were studied. Temperature and humidity sensitive properties were also tested. The results show that the sensor can detect NH3 with high sensitivity, whereas can not recognize CO almost. The investigation of the effects of film depositing time .on sensor sensitivities shows that the sensors with the composite thin film deposited for 20min possess the highest sensitivity to NH3.