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Silviu Cosmin Sandu

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Related publications (45)

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Ex-situ AlN seed layer for (0001)-textured Al0.84Sc0.16N thin films grown on SiO2 substrates

Paul Muralt, Silviu Cosmin Sandu, Stefan Mertin, Fazel Parsapour, Vladimir Pashchenko

It is more difficult to nucleate AlN-ScN alloy thin films (AlScN) in pure (0001)-texture than it is with pure AlN thin films. AlN thus can serve as seed layer for AlScN. Equipment limitations may lead to the problem of a vacuum break between AlN and AlScN ...

Ieee2017

Nanoscale triboactivity: The response of Mo–Se–C coatings to sliding

Silviu Cosmin Sandu

Mo–Se–C films were deposited by sputtering from a carbon target with pellets of MoSe2. In addition to the standard evaluation of their chemical composition, structure, morphology, hardness and cohesion/adhesion, the core objective of this paper was to anal ...

2008

A combinatorial chemical beam vapour deposition approach to tune the electrical conductivity of Nb:TiO2 films via Si co-doping

Paul Muralt, Silviu Cosmin Sandu, Giacomo Benvenuti, Estelle Wagner, Scott Harada

Chemical beam vapour deposition (CBVD) is a thin film deposition technique operated under high vacuum conditions in which film growth occurs through the thermally activated chemical decomposition of precursor molecules at the substrate surface. This techni ...

Elsevier Science Sa2016

Low resistivity Ru1-xTixO2 thin films deposited by hybrid high-power impulse magnetron sputtering and direct current magnetron sputtering technique

Alireza Karimi, Arnaud Magrez, Silviu Cosmin Sandu, Rosendo Sanjines

The present paper reports on an experimental investigation of the structural, electrical and optical properties of Ru rich Ru1-xTixO2 thin films. Rutile single-phaseRu(1-x)Ti(x)O(2) thin films have been deposited by reactive hybrid High-power impulse magne ...

2019

Nanoscale Defect Engineering and the Resulting Effects on Domain Wall Dynamics in Ferroelectric Thin Films

Nava Setter, Dragan Damjanovic, Silviu Cosmin Sandu, Ludwig Feigl

Defect engineering is one of the cornerstones of the modern electronics industry. Almost all electronic devices include materials that have been doped by ion bombardment. For materials where crystallinity is essential, such as ferroelectrics, defect type a ...

Wiley-Blackwell2017

Properties of nanocomposite film combining hard TiN matrix with embedded fullerene-like WS2 nanoclusters

Silviu Cosmin Sandu

We have developed hard self-lubricant coatings combining a hard matrix (TiN) and a self-lubricant phase in the form of inorganic-like WS2 fullerene. The nanoparticles were injected from the preparation chamber directly to the sample surface during reactive ...

2011

Highly piezoelectric AlN thin films grown on amorphous, insulating substrate

Paul Muralt, Silviu Cosmin Sandu

AlN thin films were grown by reactive sputtering on amorphous SiO2 thin films. Film texture, x-ray rocking curve width, mechanical stress, and the clamped piezoelectric constant d33,f were studied as a function of rf bias power and substrate roughness. A h ...

2010

Control of morphology (ZrN crystallite size and SiNx layer thickness) in Zr-Si-N nanocomposite thin films

Rosendo Sanjines, Silviu Cosmin Sandu

DC reactive magnetron sputtering was used for the deposition of Zr–Si–N thin films. Four series of samples have been deposited at various substrate temperatures TS: 300 K, 510 K, 710 K and 910 K. Depending on TS, different N2 partial pressures pN2 were req ...

2008

Controlled creation and displacement of charged domain walls in ferroelectric thin films

Nava Setter, Silviu Cosmin Sandu, Tomas Sluka, Ludwig Feigl

Charged domain walls in ferroelectric materials are of high interest due to their potential use in nanoelectronic devices. While previous approaches have utilized complex scanning probe techniques or frustrative poling here we show the creation of charged ...

Nature Research2016

Enhanced piezoelectric properties of c-axis textured aluminium scandium nitride thin films with high scandium content: influence of intrinsic stress and sputtering parameters

Paul Muralt, Silviu Cosmin Sandu, Gabriel Christmann, Stefan Mertin, Clemens Benedict Nyffeler, Fazel Parsapour, Vladimir Pashchenko

Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN), which makes it an upcoming piezoelectric material for use in next generation RF filters, sensors, actuators and energy harvesting de ...

Ieee2017

Piezoelectric enhancement under negative pressure

Alexander Tagantsev, Nava Setter, Silviu Cosmin Sandu, Tomas Sluka, Jin Wang, Alexander Kvasov

Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expec ...

Nature Publishing Group2016

Fabrication of complex oxide microstructures by combinatorial chemical beam vapour deposition through stencil masks

Paul Muralt, Andreea Veronica Savu, Silviu Cosmin Sandu, Giacomo Benvenuti, Estelle Wagner, Scott Harada

Chemical Beam Vapour Deposition is a gas phase deposition technique, operated under high vacuum conditions, in which evaporated chemical precursors are thermally decomposed on heated substrates to form a film. In the particular equipment used in this work, ...

Elsevier2015

Mechanism of hydrothermal growth of ferroelectric PZT nanowires

Nava Setter, Silviu Cosmin Sandu, Jin Wang, Alexandre Durussel

The formation mechanism of hydrothermally grown monocrystalline ferroelectric PZT nanowires is investigated. It is shown that the growth proceeds via a two-step process. Particles of the centrosymmetric PX-phase grow initially, having a fibrous morphology ...

2012

Controlled stripes of ultrafine ferroelectric domains

Alexander Tagantsev, Nava Setter, Igor Stolichnov, Silviu Cosmin Sandu, Tomas Sluka, Ludwig Feigl, Petr Yudin, Konstantin Shapovalov, Mahamudu Mtebwa

In the pursuit of ferroic-based (nano) electronics, it is essential to minutely control domain patterns and domain switching. The ability to control domain width, orientation and position is a prerequisite for circuitry based on fine domains. Here, we deve ...

Nature Publishing Group2014

Combinatorial Discovery and Optimization of Amorphous HfO2-Nb2O5 Mixture with Improved Transparency

Paul Muralt, Patrik Willi Hoffmann, Silviu Cosmin Sandu, Ali Dabirian, Giacomo Benvenuti, Estelle Wagner, Yury Kuzminykh, Scott Harada

Combinatorial high vacuum chemical vapor deposition (HV-CVD) of mixed HfO2-Nb2O5 thin films has been demonstrated to yield amorphous layers at substrate temperatures where individually deposited pure HfO2 and Nb2O5 films are polycrystalline. Spectroscopic ...

Electrochemical Society2010

TEM investigation of MoSeC films

Silviu Cosmin Sandu

Transition metal dichalcogenides (TMD) are widely used as self-lubricating material either as oil additive or directly as thin films. Magnetron sputtering is a deposition method allowing depositing such films with high density and adhesion. However, their ...

Cambridge University Press2008

Abnormal Grain Growth in AlScN Thin Films Induced by Complexion Formation at Crystallite Interfaces

Paul Muralt, Thomas La Grange, Stefan Mertin, Vladimir Pashchenko, Fazel Parsapour, Silviu Cosmin Sandu, Ramin Matloub Aghdam

Sputter deposited Al(1-x)ScxN thin films with a Sc content from x = 0 to 43 at% are investigated by electron microscopy in order to study and explain the formation and growth of abnormally oriented grains (AOG). It is found that the latter did not nucleate ...

Wiley-VCH Verlag2019

Synchrotron X-ray diffraction study on a single nanowire of PX-phase lead titanate

Nava Setter, Silviu Cosmin Sandu, Jin Wang

Synchrotron X-ray diffraction (XRD) measurements of Pb-Ti-O fine acicular crystals (nanowires) of the so-called PX-phase have been performed. The theta-2 theta patterns of the nanowires dispersed on substrates with two different geometries indicated that t ...

2010

Analysis of composition homogeneity and polarization orientation of PZT submicron fibers by micro-Raman spectroscopy

Nava Setter, Silviu Cosmin Sandu, Jin Wang

Micro-Raman spectroscopy is a convenient tool to probe individual objects with a feature size on the submicron scale. The phase, composition, and orientation of Pb(Zr,Ti)O-3 fibers fabricated via hydrothermal processing have been characterized by this tech ...

Elsevier Sci Ltd2014

Thickness Dependence of Domain-Wall Patterns in BiFeO3 Thin Films

Nava Setter, Silviu Cosmin Sandu, Tomas Sluka

Unique properties of domain walls in ferroelectrics have been recently discovered but methods of their controlled engineering remain underdeveloped. Here we investigate the domain structure of Bi0.9La0.1FeO3 epitaxial thin films with piezoelectric force mi ...

Taylor & Francis2015