Search results for "doping"
showing 10 items of 801 documents
Photoelectric fields in doped lithium niobate crystals
2019
Photoinduced light scattering (PILS) in nominally pure stoichiometric and congruent lithium niobate single crystals (LiNbO3), and ones doped with B³⁺, Cu²⁺, Zn²⁺, Mg²⁺, Gd³⁺, Y³⁺, Er³⁺ cations was studied. All crystals have a relatively low effect of photorefraction and are promising materials for frequency conversion, electro-optical modulators and shutters. It was found that the photovoltaic and diffusion fields for some crystals have a maximum at a wavelength of 514.5 nm. All the crystals studied are characterized by a maximum of the integral intensity of the speckle structure of the PILS at a wavelength of 514.5 nm.
Doping dependence of spin dynamics of drifting electrons in GaAs bulks
2010
We study the effect of the impurity density on lifetimes and relaxation lengths of electron spins in the presence of a static electric field in a n-type GaAs bulk. The transport of electrons and the spin dynamics are simulated by using a semiclassical Monte Carlo approach, which takes into account the intravalley scattering mechanisms of warm electrons in the semiconductor material. Spin relaxation is considered through the D'yakonov-Perel mechanism, which is the dominant mechanism in III-V semiconductors. The evolution of spin polarization is analyzed by computing the lifetimes and depolarization lengths as a function of the doping density in the range 10^{13} - 10^{16} cm^{-3}, for differ…
Structural, electrical and optical characteristics of Al-doped zinc oxide thin films deposited by reactive magnetron sputtering
2013
ZnO:Al (AZO) thin films on glass were deposited by DC reactive magnetron sputtering at approximately 300°C substrate temperature. Structural, electrical and optical properties were investigated as a function of oxygen flow. XRD data shows that AZO thin films are polycrystalline with pronounced c-axis orientation and the grain size increasing with the oxygen flow. The lowest achieved resistivity within the deposited set of samples was 7.6·10 -4 Ωcm. The transmittance of AZO films was above 80 % at 550 nm with the optical band gap between 3.4 and 3.8 eV.
Graphene‐SiO2 Interaction from Composites to Doping
2019
An overview of the interaction between monolayer graphene and SiO2 dielectric substrate is reported focusing on the effect this latter has on doping and strain induced by thermal treatments in controlled atmosphere. The disentanglement of strain and doping is highlighted and the comparison with another dielectric substrate of Al2O3 evidences the critical role that the substrate has in the electronic properties of graphene. The reported results pave the way for microelectronic devices based on graphene on dielectrics and for Fermi level tuning in composites of graphene and nanoparticles.
A new intermediate intercalate in superconducting sodium-doped hafnium nitride chloride
2005
Anew phase has been observed during the sodiumintercalation of hafnium nitride chloride as intermediate between the host β-HfNCl and the already reported Na 0.29 HfNCl with Tc of 24 K; the new intermediate shows interlayer spacings ranging from 9.48 to 9.67 A°, corresponds to a second stage intercalate of HfNCl and is superconducting with a critical temperature of 20 K. Beltran Porter, Daniel, Daniel.Beltran@uv.es
Strain relaxation, extended defects and doping effects in InxGa1-xN/GaN heterostructures investigated by surface photovoltage
2020
Abstract We have analysed electrical properties of extended defects and interfaces in fully strained and partially relaxed InxGa1-xN/GaN heterostructures by means of Kelvin probe force microscopy and surface photovoltage spectroscopy. The study highlights the role of indium incorporation and Si doping levels on the charge state of extended defects including threading dislocations, V defects and misfit dislocations. Surface potential maps reveal that these defects are associated with a different local work function and thus could remarkably alter electron-hole recombination mechanisms of InxGa1-xN/GaN layers locally. Surface photovoltage spectra clearly demonstrate the role of misfit disloca…
Dynamically Doped White Light Emitting Tandem Devices
2013
Solution-processed, salt-containing, blue and orange light-emitting layers lead to efficient white light-emitting devices when arranged in a tandem configuration separated by a thin metal layer.
Sol-gel assisted molten-salt synthesis of novel single phase Y3–2xCa2xTaxAl5−xO12:1%Eu garnet structure phosphors
2022
Strong absorption and emission are the key the features of any phosphor. The results obtained during this study demonstrate the difficulty of the incorporation of tantalum ions into the garnet structure and reveal that only the combination of Sol-Gel synthesis method together with Molten-Salt technique enable to obtain a single-phase cubic garnet structure. Note that, the Sol-Gel synthesis assisted by further processing by Molten-Salt technique can be a potentially new way of material preparation reported in literature. This work also proves that this combination of synthesis methods is much more capable of incorporating ions with large ionic radii into the garnet structure as compared to t…
Thin Film Organic Thermoelectric Generator Based on Tetrathiotetracene
2017
This is the peer reviewed version of the following article: K. Pudzs, A. Vembris, M. Rutkis, S. Woodward, Adv. Electron. Mater. 2017, 1600429, which has been published in final form at http://onlinelibrary.wi...002/aelm.201600429/full This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Structural and electrical properties of magnetron sputtered Ti(ON) thin films:The case of TiN doped in situ with oxygen.
2009
International audience; Incorporation of oxygen into TiN lattice results in formation of titanium oxynitrides, TiOxNy that have become particularly interesting for photocatalytic applications. Elaboration as well as characterization of TiN and in situ oxygen-doped thin films is the subject of this paper. Thin films, 250–320nm in thickness, have been deposited by dc-pulsed magnetron reactive sputtering from Ti target under controllable gas flows of Ar, N2 and O2. Optical monitoring of Ti plasma emission line at = 500nm has been implemented in order to stabilize the sputtering rate. Scanning electron microscopy (SEM), X-ray diffraction in grazing incidence (GIXRD), micro-Raman spectroscopy, X…