Dr. Ardyanian was born in Tehran, Iran. He received undergraduate degrees in applied physics (Solid State Physics) from Ferdowsi University, Mashhad, Iran (1993) and in Solid State Physics from Nancy University, France (2004). He earned a Ph.D. in Applied Condensed Matther Physics from Nancy University, France, (2007). He then held faculty position at the Damghan University, Semnan, Iran.
His Administrative portfolio includes vice dean of school of physics. He is currently Head of Solid State Department and assistant professor of condensed matter physics in Damghan university.
His research area lies in Synthesize and Characterization of Transparent Conductive Oxide Specially Zinc-Oxide nano-structures and nano-composites; and Zeolites.
INDEX KEYWORDS: Atomic emission spectroscopy; Chemical detection; Energy dispersive spectroscopy; Energy gap; Gas detectors; Gas sensing electrodes; High resolution transmission electron microscopy; II-VI semiconductors; Inductively coupled plasma; Methane; Nanoparticles; Scanning electron microscopy; Synthesis (chemical); Transmission electron microscopy; X ray diffraction; Zinc oxide; Zinc sulfide; ZnO nanoparticles, Energy dispersive X ray spectroscopy; Gas sensing properties; Hexagonal wurtzite structure; Inductively coupled plasma atomic emission spectroscopy; Methane-gas sensing; Nanoparticles sizes; Scanning and transmission electron microscopy; Solvothermal method, Cobalt compounds PUBLISHER: Springer New York LLC
INDEX KEYWORDS: Bond strength (chemical); Coatings; Electron emission; Electron microscopy; Energy gap; Field emission microscopes; Film preparation; High resolution transmission electron microscopy; Multilayers; Nanoparticles; Near infrared spectroscopy; Optical emission spectroscopy; Optical multilayers; Optical properties; Scanning electron microscopy; Sols; Spin glass; Substrates; Synthesis (chemical); Titanium dioxide; Titanium oxides; Transmission electron microscopy; X ray diffraction; Zinc compounds; Zinc oxide; Zinc sulfide, Fabrication and characterizations; Field emission scanning electron microscopy; Fourier transform infra reds; Spin-coating method; Thin films-thickness; TiO2 nano-particles; Titanium dioxides (TiO2); UV-vis-NIR spectroscopy, Titanium compounds PUBLISHER: Springer New York LLC
INDEX KEYWORDS: Ammonia; Ammonium persulfate; Electron microscopy; Enamels; Energy gap; Ethylene; Ethylene glycol; Field emission microscopes; High resolution transmission electron microscopy; Molybdenum compounds; Molybdenum oxide; Nanoparticles; Scanning electron microscopy; Sols; Transmission electron microscopy; X ray diffraction analysis, Annealing temperatures; Chalcogenide semiconductors; Field emission scanning electron microscopy; Hexagonal structures; Molybdenum disulfide; Molybdenum sulfide; Porous nanoparticles; Synthesis and characterizations, Synthesis (chemical) PUBLISHER: Springer New York LLC
INDEX KEYWORDS: Annealing; Electron microscopy; Enamels; Energy gap; Field emission microscopes; Fourier transform infrared spectroscopy; High resolution transmission electron microscopy; Layered semiconductors; Molybdenum; Molybdenum compounds; Nanoparticles; Nanostructures; Scanning electron microscopy; Sulfur; Synthesis (chemical); Transmission electron microscopy; X ray diffraction analysis, Annealing temperatures; Chalcogenide semiconductors; Characteristic bands; Chemical reduction methods; Field emission scanning electron microscopy; Hexagonal structures; Homogeneous distribution; Molybdenum disulfide, Molybdenum oxide PUBLISHER: Springer Verlag
Zinc oxide-Tin oxide (ZnO-SnO) binary thin films were prepared on the glass substrates by spray pyrolysis method. The variation range of the molar ratio of x = [Sn]/[Zn] considered to be changed from 5% to 50%. The films characterized by using the X-ray diffraction (XRD) technique, UV-Vis-NIR spectroscopy, Hall effect, Seebeck effect, electrical and photoconductivity measurements. Using the scanning electron microscopy (SEM) and atomic force microscopy (AFM) images the morphology and roughness of the thin films surfaces were obtained, respectively. AFM micrographs indicate the decrease of roughness by increasing the dopant (Sn) concentration (x). XRD results describe the existence of the ZnO, SnO, SnO2, ZnSnO3 and Zn2SnO4 phases for various x values. The optical band gap and transmittance were obtained from UV-Vis-NIR spectroscopy results as a function of x. The results show a general band gap narrowing which occurs with the increasing of the Sn concentration which attributed to the structure and many body effects. Moreover, comparing to ZnO thin films, the remarkable decrease of the electrical conductivity and optical transparency were observed at the low x values. The conduction type was determined by the Hall effect and thermoelectric measurements. The Seebeck effect measurements show for â̂†T ≤ 185 K, the electrons are the majority carriers, which replaced with the holes for â̂†T > 185 K. Power factor quantity was measured as a function of the Sn concentration and temperature. Furthermore, the power factor determines the best x value for the optimal electrical properties. Photoconductivity property was also observed in all samples which weakened for x ≤ 30%, and increased for the higher x values.
AUTHOR KEYWORDS: Atomic force microscopy; Binary system; Photoconductivity; Spray pyrolysis; Thermoelectricity; Tin oxide; X-ray diffraction; Zinc oxide INDEX KEYWORDS: Band gap narrowing; Binary systems; Electrical conductivity; Optical transparency; Seebeck effect measurements; Spray pyrolysis method; Thermoelectric measurements; UV-vis-NIR spectroscopy, Atomic force microscopy; Electric power factor; Electric properties; Film preparation; Hall effect; Infrared devices; Photoconductivity; Scanning electron microscopy; Spray pyrolysis; Substrates; Systems (metallurgical); Thermoelectricity; Thin films; Tin oxides; X ray diffraction; Zinc; Zinc oxide, Tin
Germanium nanostructures were generated in the post annealed germanium oxide thin films. Visible and near infrared photoluminescence bands were observed in the samples annealed at 350°C and 400°C, respectively. These different luminescence ranges are attributed to the presence of the defects in oxide matrix and quantum confinement effect in the germanium nanostructures, respectively. Decay time and temperature dependence of the luminescence for different bands were investigated, which confirmed our idea about the origin of the luminescence.
AUTHOR KEYWORDS: Germanium; Nanostructures; Photoluminescence; Temperature dependence
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