Publications de Paul Muralt | EPFL Graph Search

Tailoring dielectric permittivity of epitaxial Gd-doped CeO2-x films by ionic defects

Engineering materials with highly tunable physical properties in response to external stimuli is a cornerstone strategy for advancing energy technology. Among various approaches, engineering ionic defects and understanding their roles are essential in tail ...

Iop Publishing Ltd2024

Piezoelectric thin films for MEMS

Paul Muralt

AIP Publishing2023

Controlled Electronic and Magnetic Landscape in Self-Assembled Complex Oxide Heterostructures

Paul Muralt, Mihai Adrian Ionescu, Kanghyun Chu, Daesung Park

Complex oxide heterointerfaces contain a rich playground of novel physical properties and functionalities, which give rise to emerging technologies. Among designing and controlling the functional properties of complex oxide film heterostructures, verticall ...

Wiley-V C H Verlag Gmbh2023

Induced giant piezoelectricity in centrosymmetric oxides

Dragan Damjanovic, Paul Muralt, Mahmoud Hadad, Vasiliki Tileli, Lukas Riemer, Daesung Park

Piezoelectrics are materials that linearly deform in response to an applied electric field. As a fundamental prerequisite, piezoelectric materials must have a noncentrosymmetric crystal structure. For more than a century, this has remained a major obstacle ...

American Association for the Advancement of Science2022

Self-Poled Heteroepitaxial Bi(1-x)DyxFeO3 Films with Promising Pyroelectric Properties

Paul Muralt

Pyroelectric materials are very promising for thermal energy harvesting applications. To date, lead-based systems are the foremost studied materials in this field. A facile and simple metal organic chemical vapor deposition route is applied for the fabrica ...

2022

Fabrication, Characterization, and Simulation of Glass Devices with AlN Thin-Film Transducers for Excitation of Ultrasound Resonances

Paul Muralt, Ramin Matloub Aghdam

We present the fabrication of 570-mu m-thick millimeter-sized soda-lime-silicate float-glass blocks with a 1-mu m-thick AlN thin-film piezoelectric transducer sandwiched between thin metallic electrodes and deposited on the top surface. The electromechanic ...

American Physical Society (APS)2021

Optimization of Resonant PZT MEMS Mirrors by Inverse Design and Electrode Segmentation

Paul Muralt, Ramin Matloub Aghdam

This paper presents a systematic approach to transduction optimization of resonant piezo-based MEMS devices. The method is based on inverse design approach using direct piezoelectric effect and exploits mechanical action of desired mode to calculate the po ...

Institute of Electrical and Electronics Engineers2021

Guest Editorial

Paul Muralt

TAYLOR & FRANCIS LTD2020

Actuation of piezoelectric structures with ferroelectric thin films having multiple elements

Paul Muralt

A method for driving piezoelectric elements of a micro-system. The piezoelectric elements comprising a ferroelectric thin film, and being configured to be part of any one or a combination of items of a list comprising: a cantilever, a bridge, a diaphragm, ...

2020

Resonant Pzt Mems Mirror With Segmented Electrodes

Paul Muralt, Mohssen Moridi, Ramin Matloub Aghdam

We report a transduction optimization method of piezo-based MEMS structures using segmentation of the excitation electrodes. Optimal transduction is achieved by matching the electric field distribution to the polarization distribution including the direct ...

IEEE2020

Fuel cell system for portable applications

Paul Muralt, Mahmoud Hadad

In a fuel cell system component, the fuel cell system component comprises a glass ceramic composite. ...

2020

The emergence of magnetic ordering at complex oxide interfaces tuned by defects

Paul Muralt, Yen-Chun Chen, Vasiliki Tileli, Daesung Park, Gurpreet Singh, Jing Li

Complex oxides show extreme sensitivity to structural distortions and defects, and the intricate balance of competing interactions which emerge at atomically defined interfaces may give rise to unexpected physics. In the interfaces of non-magnetic complex ...

Nature Research2020

Impact of negative bias on the piezoelectric properties through the incidence of abnormal oriented grains in Al0.62Sc0.38N thin films

Paul Muralt, Thomas La Grange, Silviu Cosmin Sandu, Mohammad Fazel Parsapour Kolour, Xiao Di, Robin Nigon, Lukas Riemer

Sputter deposited A1ScN films with an Sc content of 38 at % were investigated by X-ray diffraction and electron microscopy to study the influence of the radio frequency (RF) bias on the growth of abnormally oriented grains (AOG). Scanning electron microsco ...

2020

Non-destructive piezoelectric characterisation of Sc doped aluminium nitride thin films at wafer level

Paul Muralt, Clemens Benedict Nyffeler, Stefan Mertin, Andrea Mazzalai

Scandium doped aluminium nitride (ScAlN) gained much attention during last years, since its piezoelectric response is much enlarged as compared to pure AlN films. Above 30% Sc the films are of high interest for piezoMEMS sensing and actuation, ultrasound g ...

IEEE2019

Vibration Mode of MEMS Ultrasonic Sensors on Buckled Diaphragms with Piezoelectric Resonance Frequency Modification

Paul Muralt, Kaoru Yamashita

Vibration mode and resonance frequency of piezoelectric MEMS ultrasonic sensors was investigated on buckled diaphragm structures. The buckling of the diaphragms was introduced intrinsically through residual stress control of the piezoelectric film, and ext ...

IEEE2019

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

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

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

Material Parameter Extraction for Complex AlScN Thin Film Using Dual Mode Resonators in Combination with Advanced Microstructural Analysis and Finite Element Modeling

Paul Muralt, Thomas La Grange, Silviu Cosmin Sandu, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko, Kaoru Yamashita

Accurate property determination of the piezoelectric thin film material Al(1-x)Sc(x)N is necessary for designing the next generation of radio frequency resonators in mobile communication, and for testing results of ab initio calculations. Sound velocity an ...

WILEY2019

Al0.83Sc0.17N Contour-Mode Resonators With Electromechanical Coupling in Excess of 4.5%

Paul Muralt, Luis Guillermo Villanueva Torrijo, Andrea Lozzi

In this paper, we demonstrate the fabrication of contour-mode resonators (CMRs) with Al0.83Sc0.17N as a piezoelectric layer. Moreover, we assess the electromechanical coupling and the maximum achieved quality factor from 150 to 500 MHz. In comparison to pu ...

2019

Transient Negative Capacitance of Silicon-doped HfO2 in MFMIS and MFIS structures: experimental insights for hysteresis-free steep slope NC FETs

Paul Muralt, Igor Stolichnov, Mihai Adrian Ionescu, Ali Saeidi, Matteo Cavalieri, Carlotta Gastaldi

In this paper, we experimentally explore the transient negative capacitance effect in ferroelectric high-k gate stacks using multi-ferroelectric domain Si-doped HfO2 with and without the metal plane, MFMIS (TiN/Si:HfO2/TiN/SiO2) and MFIS (TiN/Si:HfO2/SiO2) ...

IEEE2019

Growth, Properties, and Applications of Al1-xScxN Thin Films

Paul Muralt, Stefan Mertin, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko

The discovery of enhanced piezoelectricity in solid solutions of AlN and ScN is certainly one of the most important events in piezoelectric MEMS. As compared to pure AlN, it brought a crucial factor 2 to 3 improvement in a number of figures of merit govern ...

IEEE2019