Effect of annealing on properties of decorative zirconium oxynitride thin films

Zirconium oxynitrides are excellent candidates for many technological applications, especially decorative applications. For the use of zirconium oxynitrides as decorative coatings, the thermal stability is of crucial importance. Therefore zirconium oxynitrides, containing both oxygen and nitrogen, were prepared by pulsed d.c. reactive magnetron sputtering at ƤN2 / (ƤN2 + ƤO2) of 0.98. The as-prepared films were annealed in air for 1 h. The full set of annealing was 100, 200, 300, 400, 450, 500 and 550°C. The annealed zirconium oxynitride films exhibited nitrogen loss (oxidation). The nitrogen loss results in a great variance in compositional, electrical and optical properties. The energy dispersive analysis of X-ray and X-ray diffraction were used to examine the compositional and structural properties, respectively. A huge increase in the electrical resistivity was observed upon oxidation. The films annealed at higher temperatures (≥450°C) showed insulating behavior with low extinction coefficient (<1) and reasonable refractive index values. The optical band gap values of the films annealed at 500°C and 550°C are in good agreement with the previously reported values for ZrO2

Highly crystalline hexagonal PbI2 sheets on polyaniline/antimony tin oxide surface as a novel and highly efficient photodetector in UV, Vis, and near IR regions

International audienceThe work reports on the preparation of polyaniline/lead iodide optoelectronic photodetector on antimony tin oxide (ATO) glass (PANI/PbI2/ATO) for providing a low-cost light sensor in the UV, Vis, and near IR regions (wide optical range photodetector). The deposition of PbI2 nanoparticles was carried out on the surface of PANI using the ionic adsorption deposition method. Four ATO/PANI/PbI2 composites (I, II, III, and IV) were produced by varying the Pb2+ concentrations (0.01, 0.03, 0.05, and 0.07 M, respectively). The chemical structure, morphology, optical, and electrical properties were assessed using different analytical tools. Scanning electron microscopy (SEM) imaging revealed the formation of a nanoporous PANI network. After PbI2 incorporation within the PANI network, white nanoparticles formed on the surface. The average size of the PbI2 nanoparticles was 220, 270, 280, and 320 nm for Pb2+ concentration of 0.01, 0.03, 0.05, and 0.07 M, respectively. Moreover, x-ray diffraction analysis confirmed PANI/PbI2 composite formation, as witnessed by the appearance of new peaks at 12.77 degrees, 34.31 degrees, and 38.8 degrees characteristic of PbI2. Through the optical analyses, the band gap values of the PANI/PbI2 composites I, II, III, and IV were 2.63, 2.51, 2.46, and 2.48 eV, respectively. ATO/composite III was applied as an optoelectronic device for detection the light under different intensities or wavelengths, in which the current density (J(ph)) increase from 2.5 to 3.42 mA cm(-2) upon increasing of the light intensity from 25 to 100 mW.cm(-2), respectively. Moreover, the J(ph) recorded an optimum value of 3.33 mA cm(-2) at 390 nm, which decreased to 2.09 mA cm(-2) at 490 nm and increased again to 3.13 mA cm(-2) at 636 nm. The optoelectronic photodetector exhibited an optimum incident photon to electron conversion efficiency (IPCE) of 10.7% at 390 nm. The photoresponsivity (R) and detectivity (D) were determined to be 107 mA cm(-2) and 3.38 x 10(10) Jones, respectively. Finally, a simple mechanism was proposed to account for the response of the prepared optoelectronic devices to the photon flux. Soon, our team will work on design an optoelectronic device that can be applied in the industrial field through the high technology device such as cameras and aircrafts for light detection