Search results for "21"

Deposition of binder-free oxygen-vacancies NiCo2O4 based films with hollow microspheres via solution precursor thermal spray for supercapacitors

2019

Abstract Hollow micro-/nanostructures and oxygen vacancies are highly desirable for supercapacitors due to high active surface area and outstanding electrochemical properties. In order to benefiting from the both effect, binder-free oxygen-vacancies NiCo2O4 based films with hollow microspheres were pioneering directly deposited via one kind thermal spray technology, named solution precursor thermal spray (SPTS) process. To our best knowledge, the rapid one-step SPTS route was firstly employed to synthesize and deposit NiCo2O4 films for supercapacitor applications. The CV data clearly demonstrated that the specific capacitances of more oxygen-deficient NiCo2O4 electrodes with hollow microsph…

High transparency Bi 2 Se 3 topological insulator nanoribbon Josephson junctions with low resistive noise properties

2019

Bi$_2$Se$_3$ nanoribbons, grown by catalyst-free Physical Vapour Deposition, have been used to fabricate high quality Josephson junctions with Al superconducting electrodes. The conductance spectra (dI/dV) of the junctions show clear dip-peak structures characteristic of multiple Andreev reflections. The temperature dependence of the dip-peak features reveals a highly transparent Al/Bi$_2$Se$_3$ topological insulator nanoribbon interface and Josephson junction barrier. This is supported by the high values of the Bi$_2$Se$_3$ induced gap and of I$_c$R$_n$ (I$_c$ critical current, R$_n$ normal resistance of the junction) product both of the order of 160 $\mu$eV, a value close to the Al gap. T…

Effect of surface disorder on the domain structure of PLZT ceramics

2017

ABSTRACTPb1-xLax(Zr0.65Ti0.35)1-x/4O3 (PLZT x/65/35) ceramics were studied by Piezoresponse Force Microscopy in order to understand the origin of domain structure as a function of La content. We show that the domain topology is mainly determined by the composition and grain size. The characteristic correlation length decreases with increasing La content, being sensitive also to the synthesis method. The behavior of the correlation length is linked to the macroscopic properties, showing a strong increase of disorder with La doping. The roughness exponent for the domain wall in PLZT 9/65/35 is close to 2/3 indicating 1D character of domain walls in relaxors.

Optical studies of MBE-grown InN nanocolumns: Evidence of surface electron accumulation

2009

Finite element analysis of stress concentration between surface coated implants and non surface coated implants - An in vitro study.

2019

Background To determine qualitative comparison in stress distribution between surface coated implants and non surface coated implants using 2 different lengths and vertical, oblique, and lateral forces. Material and Methods 3 dimensional finite element study was carried out at first molar site with 4 surface coated and 4 non surface coated implants using mimic 8.11, solid edge 2004, hypermesh 9.0, and ansys12.1 software. Results The pattern of stress distribution was almost similar between vertical and oblique loading but varied with lateral loads between surface coated and non surface coated implants. As the length of the implants increased stress concentration had no significant variation…

ZnMgO-based UV photodiodes: a comparison of films grown by spray pyrolysis and MBE

2016

Detecting the UV part of the spectrum is fundamental for a wide range of applications where ZnMgO has the potential to play a central role. The shortest achievable wavelength is a function of the Mg content in the films, which in turn is dependent on the growth technique. Moreover, increasing Mg contents lead to an electrical compensation of the films, which directly affects the responsivity of the photodetectors. In addition, the metal-semiconductor interface and the presence of grain boundaries have a direct impact on the responsivity through different gain mechanisms. In this work, we review the development of ZnMgO UV Schottky photodiodes using molecular beam epitaxy and spray pyrolysis…

Optical properties and microstructure of 2.02-3.30 eV ZnCdO nanowires: effect of thermal annealing

2013

International audience; ZnCdO nanowires with up to 45% Cd are demonstrated showing room temperature photoluminescence (PL) down to 2.02 eV and a radiative efficiency similar to that of ZnO nanowires. Analysis of the microstructure in individual nanowires confirms the presence of a single wurtzite phase even at the highest Cd contents, with a homogeneous distribution of Cd both in the longitudinal and transverse directions. Thermal annealing at 550 C yields an overall improvement of the PL, which is blue-shifted as a result of the homogeneous decrease of Cd throughout the nanowire, but the single wurtzite structure is fully maintained.

Thermal oxidation of the intermetallic phases Al 8 Mo 3 and AlMo 3

2017

Abstract The thermal oxidation reactions of the intermetallic phases Al8Mo3 and AlMo3 were investigated and analyzed by ex-situ powder-x-ray diffraction (XRD), difference thermal analysis (DTA), thermogravimetry (TGA), and infrared spectroscopy (IR). The initial oxidation reactions in air were found to yield Al2O3 and AlMo3 in the case of Al8Mo3 (Tonset =725 °C), and MoO3 as well as Al8−xMo3 (Tonset =435 °C) for the pure intermetallic phase AlMo3, respectively. Thus, both intermetallic phases are coexisting in an equilibrium within a temperature range of 300 °C under oxidizing conditions. The formation of β-Al2(MoO4)3 followed the second oxidizing process of the respective minority componen…

Controlled thermal oxidation of nanostructured vanadium thin films

2016

Abstract Pure V thin films were dc sputtered with different pressures (0.4 and 0.6 Pa) and particle incident angles α of 0°, 20° and 85°, by using the GLancing Angle Deposition (GLAD) technique. The sputtered films were characterized regarding their electrical resistivity behaviour in atmospheric pressure and in-vacuum conditions as a function of temperature (40–550 °C), in order to control the oxidation process. Aiming at comprehending the oxidation behaviour of the samples, extensive morphological and structural studies were performed on the as-deposited and annealed samples. Main results show that, in opposition to annealing in air, the columnar nanostructures are preserved in vacuum con…

Oxy-nitrides characterization with a new ERD-TOF system

2017

Abstract A new time-of-flight (TOF) camera was installed on Elastic Recoil Detection (ERD) measurement setup on the Tandem Accelerator at Universite de Montreal. The camera consists of two timing detectors, developed and built by the Jyvaskyla group, that use a thin carbon foil and microchannel plates (MCP) to produce the start and stop signals. The position of the first detector is fixed at 18 cm from the target, while the position of the second detector can be varied between 50 and 90 cm from the first detector. This allows to increase time resolution by increasing the distance between the time-of-flight detectors or to increase solid angle by decreasing the distance. Moving the detector …