002 to 0.005 Ω cm. The anodization process was carried out using an electrolyte solution composed of hydrofluoric acid (48 wt% HF) and ethanol (99.9 %) in a volumetric ratio of 1:1. The bilayer porous structure

was fabricated with a current Crenigacestat solubility dmso density of J 1 = 31.64 mA/cm2 (refractive index, n 1 = 1.5) and J 2 = 13.3 mA/cm2 (refractive index, n 2 = 1.8). ZnO thin films were deposited on PS using sol-gel spin coating. In this process, zinc acetate dehydrate [Zn(CH3COO)2 · H2O] was first dissolved into the ethanol solution along with monoethanolamine (MEA). A homogeneous transparent solution with a concentration of 0.2 M zinc acetate and a 1:1 molar ratio of MEA/zinc acetate dehydrate was prepared. This solution was kept for hydrolysis for 48 h and spin coated onto the PS GSK2879552 nmr substrate seven times to get the desired film thickness. In order to study the stability and the good quality of ZnO, thin films were deposited on a Corning glass substrate (Corning Inc., Corning, NY, USA) and the transmittance selleck chemical measurements were taken with a PerkinElmer UV-Vis-NIR (Lambda 950) spectrophotometer (PerkinElmer, Waltham, MA, USA). To study the effect of annealing on the morphology of the ZnO film, samples were annealed in air atmosphere at 700°C for 30 min inside a tubular furnace. The orientation and crystallinity of the ZnO

crystallites were measured by an X-ray diffraction Quinapyramine (XRD) spectrometer (X’Pert PRO, PANalytical B.V., Almelo, The Netherlands) using CuKα radiation having a wavelength of 1.54 Å. The morphological effect of ZnO thin films with annealing was analyzed with a scanning electron microscope. The PL studies were carried out using a Varian fluorescence spectrometer (Cary Eclipse, Varian Inc., Palo Alto, CA, USA) under 3.8-eV excitation of a xenon lamp. The effect of the PS substrate on the electrical properties of the device (ZnO-PS) was studied by the acquisition of current-voltage curves applying DC voltage in a cyclic scan (from −10 to 10 V) at room temperature. Contacts were made of conductive carbon

in two different configurations: lateral and transversal. A reference sample was fabricated and characterized by depositing ZnO on crystalline silicon. Results and discussion To check the quality of the ZnO film, its transmittance properties were analyzed as shown in (Figure 1) [18]. The absorption coefficient (α) is obtained using the following equation: Figure 1 Tauc plot and X-ray diffraction pattern. (a) Tauc plot: optical absorption coefficient (αhv)2 vs. phonon energy (hv) of the ZnO thin film deposited on the Corning glass substrate. The inset shows the optical transmittance of the ZnO thin film on the Corning substrate. (b) X-ray diffraction pattern of the ZnO film after annealing at 700°C. where T is the optical transmittance and d is the thickness of the ZnO thin film.