Optical properties of ZnO/MgF2 bilayer thin films prepared by PVD technique

Zinc Oxide (ZnO) is considered as one of the best materials already used as a window layer in solar cells due to its antireflective capability. The ZnO/MgF2 bilayer thin film is more efficient as antireflective coating. In this work, ZnO and ZnO/MgF2 thin films were deposited on glass substrate using pulsed laser deposition and thermal evaporation deposition methods. The optical measurements indicated that ZnO thin layer has an energy gap of (3.02 eV) while ZnO/MgF2 bilayer gives rise to an increase in the energy gap. ZnO/MgF2 bilayer shows a high energy gap (3.77 eV) with low reflectance (1.1-10 %) and refractive index (1.9) leading to high transmittance, this bilayer could be a good candidate optical material to improve the performance of solar cell window.

Preparation of Bi4Te3 highly oriented nanopillars array film with enhanced electrical properties

The Bi4Te3 films with well-ordered orientation and microstructure were successfully prepared on SiO2 substrate by a vacuum thermal evaporation deposition technique for the first time. We discussed the effects of evaporation temperature and substrate temperature on the phase and its well-ordered growth of Bi4Te3 films. The formation of Bi4Te3 phase is owing to the differences of the saturated vapor pressure. The thermoelectric transport properties of the Bi4Te3 films were investigated and the (00l)-oriented nanopillars array film has a better electrical transport performance, whose value of PF is 0.032 mWm−1 K−2 at 339 K, approaching twice that of the non-oriented ordinary film. The enhanced electrical properties of Bi4Te3 films could be achieved via the high-crystallinity well-controlled (00l)-oriented nanopillars array.

Deposition of Polymer Sensor Films on SAW Surface by Electrospraying Technology

One of the most important problems with regard to the Surface Acoustic Wave (SAW) gas sensors technology is the deposition of chemosensitive films exhibiting desirable chemical and physical properties. The electrospraying technology seems to be a very promising method of the film deposition in this case. It allows the chemosensitive layers to be obtained out of almost any chemicals and their mixtures in a controllable way. The process gives the possibility to generate specific films with properties unattainable if other methods were to be applied. For example, it allows to deposit solutions of polymers and suspensions of solids in polymer solutions which can degrade in the process of thermal evaporation deposition. The paper describes the results of experiments with electrospraying technique in order to obtain Nafion® films. The influence of the process parameters on film sensitivity has been studied.

Growth and characterization of Cr doped SnO2 microtubes with resonant cavity modes

Cr doped SnO2 microtubes have been fabricated by a thermal evaporation–deposition method.