A5067880144- Semiconductor materials and devices
- Fusion materials and technologies
- Nuclear Materials and Properties
- Electronic and Structural Properties of Oxides
- Ion-surface interactions and analysis
- ZnO doping and properties
- Metal and Thin Film Mechanics
- Catalytic Processes in Materials Science
- Advanced Memory and Neural Computing
- High Entropy Alloys Studies
- Advancements in Battery Materials
- High-Temperature Coating Behaviors
- Ferroelectric and Negative Capacitance Devices
- Graphene research and applications
- Chalcogenide Semiconductor Thin Films
- Cultural Heritage Materials Analysis
- X-ray Spectroscopy and Fluorescence Analysis
- Copper Interconnects and Reliability
- Quantum Dots Synthesis And Properties
- Astro and Planetary Science
- Laser-induced spectroscopy and plasma
- Advanced Materials Characterization Techniques
- Transition Metal Oxide Nanomaterials
- Magnetic and transport properties of perovskites and related materials
- Nuclear Physics and Applications
University of Helsinki
2016-2025
Helsinki Institute of Physics
2016-2025
Finnish Museum of Natural History
2020-2022
Central South University
2020
Institute of High Energy Physics
2020
National Institute of Chemical Physics and Biophysics
2020
University of Tartu
2020
Aalto University
2011-2020
Material Physics Center
2015-2020
Wayne State University
2007
Molybdenum disulfide (MoS 2 ) is a semiconducting 2D material, which has evoked wide interest due to its unique properties. However, the lack of controlled and scalable methods for production MoS films at low temperatures remains major hindrance on way applications. In this work, atomic layer deposition (ALD) used deposit crystalline thin relatively temperature 300 °C. A new molybdenum precursor, Mo(thd) 3 (thd = 2,2,6,6‐tetramethylheptane‐3,5‐dionato), synthesized, characterized, film with...
Semiconducting two-dimensional (2D) materials are studied intensively because of their promising performance in diverse applications from electronics to energy storage and catalysis. Recently, HfS2 ZrS2 have emerged as potential rivals for the commonly 2D semiconductors such MoS2 WSe2, but use is hindered by difficulty producing continuous films. Herein, we report first atomic layer deposition (ALD) processes using HfCl4 ZrCl4 with H2S precursors. We demonstrate uniform films on a range...
Abstract 2D materials research is advancing rapidly as various new “beyond graphene” are fabricated, their properties studied, and tested in applications. Rhenium disulfide one of the transition metal dichalcogenides that has recently shown to possess extraordinary such it not limited by strict monolayer thickness requirements. The unique inherent decoupling monolayers ReS 2 combined with a direct bandgap highly anisotropic makes most interesting for plethora Here, controllable precise...
Atomic layer deposition (ALD) enables the of numerous materials in thin film form, yet there are no ALD processes for metal iodides. Herein, we demonstrate an process PbI2, a iodide with two-dimensional (2D) structure that has applications areas such as photodetection and photovoltaics. This uses lead silylamide Pb(btsa)2 SnI4 precursors works at temperatures below 90 °C, on variety starting surfaces substrates polymers, metals, sulfides, oxides. The surface defines crystalline texture...
Combining spatially resolved X-ray Laue diffraction with atomic-scale simulations, we observe how ion-irradiated tungsten undergoes a series of non-linear structural transformations increasing irradiation exposure. Nanoscale defect-induced deformations accumulating above 0.02 displacements per atom (dpa) lead to highly fluctuating strains at ~0.1 dpa, collapsing into driven quasi-steady state ~1 dpa. The asymptotic is characterized by finely dispersed vacancy defects coexisting an extended...
Reliable and accurate knowledge of the physical properties elementary point defects is crucial for predictive modeling evolution radiation damage in materials employed harsh conditions. We have applied positron annihilation spectroscopy to directly detect mono-vacancy created tungsten through particle irradiation at cryogenic temperatures, as well their recovery kinetics. find that efficient self-healing primary takes place Frenkel pair recombination already 35 K, line with an upper bound...
Molybdenum forms a range of oxides with different stoichiometries and crystal structures, which lead to properties performance in diverse applications. Herein, crystalline molybdenum oxide thin films controlled phase composition are deposited by atomic layer deposition. The MoO2(thd)2 O3 as precursors enable well-controlled growth uniform conformal at 200–275 °C. as-deposited rough and, most cases, consist mixture α- β-MoO3 well an unidentified suboxide MoOx (2.75 ≤ x 2.89) phase. can be...
Herein, we report an atomic layer deposition (ALD) process for Cu2O thin films using copper(II) acetate [Cu(OAc)2] and water vapor as precursors. This precursor combination enables the of phase-pure, polycrystalline, impurity-free at temperatures 180-220 °C. The Cu(I) oxide from a Cu(II) without use reducing agent is explained by thermally induced reduction Cu(OAc)2 to volatile copper(I) acetate, CuOAc. In addition optimization ALD parameters characterization film properties, studied in...
We present evidence of homogenization atomic diffusion properties caused by C and N interstitials in an equiatomic single-phase high entropy alloy (FeMnNiCoCr). This phenomenon is manifested unexpected interstitial-induced reduction narrowing the directly experimentally determined migration barrier distribution mono-vacancy defects introduced particle irradiation. Our observation positron annihilation spectroscopy explained state-of-the-art theoretical calculations that predict preferential...
Nickel-rich layered oxides, such as LiNi0.6Co0.2Mn0.2O2 (NMC622), are high-capacity electrode materials for lithium-ion batteries. However, this material faces issues, poor durability at high cut-off voltages (>4.4 V vs Li/Li+), which mainly originate from an unstable electrode–electrolyte interface. To reduce the side reactions interfacial zone and increase structural stability of NMC622 materials, nanoscale (<5 nm) coatings TiOx (TO) LixTiyOz (LTO) were deposited over composite electrodes...
This study reports a new meta-stable structure in epitaxial nickel-aluminum (Ni-Al) films (Al content up to 24.4 at.%) grown on MgO(001) substrates by magnetron sputtering. Structure probes XRD, HRTEM and nano-indentation combined with atomistic simulations consistently demonstrate that thin film samples coexisting {\gamma} {\gamma}' phases, domains of the two phases are homogeneously intermixed at atomic-scale, forming coherent matched lattice one overall parameter. It expands as aluminum...
Molybdenum oxide thin films are of interest due to a large range possible phases, high work functions, and catalytic activity. These have applications in areas, such as sensors, chromic, semiconductor devices. In this work, molybdenum(II) acetate dimer precursor was used with ozone for the atomic layer deposition molybdenum films. The were grown at 200–300 °C yielding highly crystalline even lowest temperatures. X-ray diffraction measurements showed that as-deposited consist suboxides and/or...
We have developed a low-temperature atomic layer deposition (ALD) process for depositing crystalline and phase pure spinel cobalt oxide (Co3O4) films at 120 °C using [Co(tBu2DAD)2] ozone as coreagent. X-ray diffraction, UV–vis spectroscopy, force microscopy, field emission scanning electron photoelectron time-of-flight elastic recoil detection analysis were performed to characterize the structure properties of films. The as-deposited Co3O4 are with low amount impurities (<2% C <5% H) despite...
Five Au(III) compounds were synthesized and evaluated for atomic layer deposition of Au thin films. One the compounds, Me2Au(S2CNEt2), showed optimal thermal characteristics while being volatile thermally stable. In growth experiments, this compound was applied with O3 at temperatures 120–250 °C. Self-limiting confirmed 180 °C a rate 0.9 Å/cycle. The deposited films uniform, polycrystalline, continuous, conductive. Typical resistivity values 40 nm thick 4–16 μΩ cm, which are low chemically...
Nucleation and conformality are important issues, when depositing thin films for demanding applications. In this study, iridium dioxide (IrO2) were deposited by atomic layer deposition (ALD), using five different processes. Different reactants, namely, O2, air, consecutive O2 H2 (O2 + H2), O3 (O3 H2) pulses used with acetylacetonate [Ir(acac)3] to deposit Ir, while IrO2 was Ir(acac)3 O3. studied a combination of methods film thickness morphology evaluation. studies, microscopic lateral...
Owing to their excellent radiation tolerance, some of the high-entropy alloys (HEAs) are considered as potential candidates for structural materials in extreme conditions. In order shed light on early-stage irradiation damage HEAs, we performed positron annihilation spectroscopy hydrogen implanted equiatomic FeMnNiCoCr and interstitial carbon-containing HEAs. We reveal primary monovacancies low dose irradiated The enhancement Frenkel pair recombination by C addition is observed C-containing...