Mohammad Arab Pour Yazdi

Bio: Mohammad Arab Pour Yazdi is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Thin film & Sputtering. The author has an hindex of 12, co-authored 38 publications receiving 433 citations. Previous affiliations of Mohammad Arab Pour Yazdi include Universite de technologie de Belfort-Montbeliard & University of Burgundy.

Optoelectronic properties of delafossite structure CuCr0.93Mg0.07O2 sputter deposited coatings

Abstract: CuCr0.93Mg0.07O2 thin films with improved optoelectronic properties were deposited by reactive magnetron sputtering on fused quartz substrates. The influence of annealing temperature under vacuum on optoelectronic properties of the films was investigated. The amorphous films annealed under vacuum at temperatures higher than 923 K are single-phased delafossite structure, while impurity phases like CuCr2O4 that affect the optoelectronic properties of the films are detected below 873 K. c-axis orientation is observed for CuCr0.93Mg0.07O2 layers and the annealing temperature window in which the films are single-phased delafossite is much larger with Mg doping (923 K → 1073 K) than that for undoped films (~953 K). The optical and electrical behaviours of the films are enhanced by Mg substitution and their direct band gap energy of about 3.12–3.14 eV is measured. The film possesses the optimum properties after annealing under vacuum at about 1023 K; its average transmittance in the visible region can reach 54.23% while the film's conductivity is about 0.27 S cm−1.

Correlation between structure and electrical resistivity of W-Cu thin films prepared by GLAD co-sputtering

Abstract: W-Cu thin films were co-deposited by magnetron sputtering using the glancing angle deposition (GLAD) method. The deposition angle of W and Cu targets was fixed at 80°, and their currents were inversely and systematically changed from 50 to 140 mA. Scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction were used to investigate the morphology and the elemental composition of the films. Electrical properties were also studied by the van der Pauw technique. An increase of the W target current and a decrease of the Cu target produced an improvement of the inclined columnar and porous structure. The W-to-Cu weight concentration ratio was tuned from 0.68 up to 19. W Cu films exhibited a diffracted signal corresponding to the (100) planes of the bcc tungsten structure for the highest W current intensities whereas the (111) peak due to the fcc copper phase was measured when the Cu target current increased. The dc electrical resistivity measured at room temperature was gradually changed from 3.59 × 10− 7 up to 9.90 × 10− 6 Ωm by means of an inverse variation of W and Cu target currents. The Cu-rich films exhibited a non-reversible resistivity vs. temperature evolution due to thermal oxidation whereas those co-sputtered with the highest W target currents showed a sudden increase of resistivity when the temperature was above 400 K.

Smart Textiles for Electricity Generation.

Abstract: Textiles have been concomitant of human civilization for thousands of years. With the advances in chemistry and materials, integrating textiles with energy harvesters will provide a sustainable, environmentally friendly, pervasive, and wearable energy solution for distributed on-body electronics in the era of Internet of Things. This article comprehensively and thoughtfully reviews research activities regarding the utilization of smart textiles for harvesting energy from renewable energy sources on the human body and its surroundings. Specifically, we start with a brief introduction to contextualize the significance of smart textiles in light of the emerging energy crisis, environmental pollution, and public health. Next, we systematically review smart textiles according to their abilities to harvest biomechanical energy, body heat energy, biochemical energy, solar energy as well as hybrid forms of energy. Finally, we provide a critical analysis of smart textiles and insights into remaining challenges and future directions. With worldwide efforts, innovations in chemistry and materials elaborated in this review will push forward the frontiers of smart textiles, which will soon revolutionize our lives in the era of Internet of Things.

RaoP-Type ZnO Materials: Theory, Growth, Properties, and Devices

Abstract: Abstract In the past 10 years, ZnO as a semiconductor has attracted considerable attention due to its unique properties, such as high electron mobility, wide and direct band gap and large exciton binding energy. ZnO has been considered a promising material for optoelectronic device applications, and the fabrications of high quality p-type ZnO and p–n junction are the key steps to realize these applications. However, the reliable p-type doping of the material remains a major challenge because of the self-compensation from native donor defects (V O and Zn i ) and/or hydrogen incorporation. Considerable efforts have been made to obtain p-type ZnO by doping different elements with various techniques. Remarkable progresses have been achieved, both theoretically and experimentally. In this paper, we discuss p-type ZnO materials: theory, growth, properties and devices, comprehensively. We first discuss the native defects in ZnO. Among the native defects in ZnO, V Zn and O i act as acceptors. We then present the theory of p-type doping in ZnO, and summarize the growth techniques for p-type ZnO and the properties of p-type ZnO materials. Theoretically, the principles of selection of p-type dopant, codoping method and X Zn –2V Zn acceptor model are introduced. Experimentally, besides the intrinsic p-type ZnO grown at O-rich ambient, p-type ZnO (MgZnO) materials have been prepared by various techniques using Group-I, IV and V elements. We pay a special attention to the band gap of p-type ZnO by band-gap engineering and room temperature ferromagnetism observed in p-type ZnO. Finally, we summarize the devices based on p-type ZnO materials.

Stronger phonon scattering by larger differences in atomic mass and size in p-type half-Heuslers Hf$_{1-x}$Ti$_{x}$CoSb$_{0.8}$Sn$_{0.2}$

Abstract: High lattice thermal conductivity has been the bottleneck for further improvement of the thermoelectric figure-of-merit (ZT) of half-Heuslers (HHs) Hf1−xZrxCoSb0.8Sn0.2. Theoretically, the lattice thermal conductivity can be reduced by exploring larger differences in the atomic mass and size in the crystal structure, leading to higher ZT. In this paper, we experimentally demonstrated that a lower thermal conductivity in p-type half-Heuslers can be achieved when Ti is used to replace Zr, i.e., Hf1−xTixCoSb0.8Sn0.2, due to larger differences in the atomic mass and size between Hf and Ti compared with Hf and Zr. The highest ZT peak, ∼1.0 at 800 °C, in the Hf1−xTixCoSb0.8Sn0.2 (x = 0.1, 0.2, 0.3, and 0.5) system was achieved using Hf0.8Ti0.2CoSb0.8Sn0.2, which makes this material useful in power generation applications.