A5028915462- Ga2O3 and related materials
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- ZnO doping and properties
- Advanced Photocatalysis Techniques
- Semiconductor Quantum Structures and Devices
- Metal and Thin Film Mechanics
- Advancements in Semiconductor Devices and Circuit Design
- Electronic and Structural Properties of Oxides
- Silicon Carbide Semiconductor Technologies
- Thermal properties of materials
- Radio Frequency Integrated Circuit Design
- Diamond and Carbon-based Materials Research
- Advanced Surface Polishing Techniques
- Electronic Packaging and Soldering Technologies
- Nanowire Synthesis and Applications
- Nanofabrication and Lithography Techniques
- Seaweed-derived Bioactive Compounds
- Advanced Cellulose Research Studies
- Nanocomposite Films for Food Packaging
- Magnetic properties of thin films
- Acoustic Wave Resonator Technologies
- Material Properties and Applications
- Polysaccharides and Plant Cell Walls
- Material Properties and Processing
Institute of Electrical Engineering of the Slovak Academy of Sciences
2015-2024
Slovak Academy of Sciences
2015-2024
SAS Institute (United Kingdom)
2024
Institute of Chemistry of the Slovak Academy of Sciences
2016-2024
Centre for Advanced Material Application of the Slovak Academy of Sciences
2022-2023
University of Bristol
2019-2021
Institute of Electrical Engineering
2020
Marshall Space Flight Center
1971-1972
We report on the growth of monoclinic β- and orthorhombic κ-phase Ga2O3 thin films using liquid-injection metal-organic chemical vapor deposition highly thermally conductive 4H-SiC substrates gallium (III) acetylacetonate or tris(2,2,6,6-tetramethyl-3,5-heptanedionato) (III). Both precursors produced β phase, while only use latter led to κ-Ga2O3. Regardless used precursor, best results for β-Ga2O3 were achieved at a temperature 700 °C O2 flows in range 600–800 SCCM. A relatively narrow...
Abstract Different phases of Ga 2 O 3 have been regarded as superior platforms for making new‐generation high‐performance electronic devices. However, understanding thermal transport in different nanoscale thin‐films remains challenging, owing to the lack phonon models and systematic experimental investigations. Here, conductivity (TC) boundary conductance (TBC) α ‐, β (001) κ ‐Ga thin films on sapphire are investigated. At ≈80 nm, measured TC (8.8 W m −1 K ) is ≈1.8 times ≈3.0 larger than...
Abstract Ga 2 O 3 , a wide-bandgap semiconductor material, offers great potential for power and high-voltage electronic devices. We report on the growth of undoped α - β -phase using liquid-injection metal-organic chemical vapor deposition (LI-MOCVD) sapphire substrates. Using same precursor (gallium acetylacetonate) temperature 700 °C, phase selection was controlled by substrate orientation, where achieved m c -plane surface, respectively. As deduced from x-ray diffraction, -Ga films show...
The oxide/semiconductor interface state density (Dit) in Al2O3/AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistor (MOS-HEMT) structures with gate oxides grown by atomic layer deposition at low temperature is analyzed this work. MOS-HEMT Al2O3 oxide were deposited 100 and 300 °C using trimethylaluminum precursor H2O O3 oxidation agents. found to show negative net charge oxide/barrier (Nint) of 1013 cm−2, which was attributed the reduction barrier surface donor (NDS). Dit...
We report on crystal structure and thermal stability of epitaxial ε/κ-Ga2O3 thin films grown by liquid-injection metal−organic chemical vapor deposition (LI-MOCVD). Si-doped Ga2O3 with a thickness 120 nm root mean square surface roughness ~1 were using gallium-tetramethylheptanedionate (Ga(thd)3) tetraethyl orthosilicate (TEOS) as Ga Si precursor, respectively, c-plane sapphire substrates at 600 °C. In particular, the possibility to discriminate between ε κ-phase X-ray diffraction (XRD)...
N-polar InN/In0.61Al0.39N heterostructures are grown directly on sapphire by using metalorganic chemical vapor deposition. The thickness of Mg-doped In0.61Al0.39N is 340 nm, and the root-mean-square surface roughness 20 nm thick InN ∼3.2 nm. An optional AlN spike at 710 °C for 35 s used either as an interlayer to separate InAlN buffer from channel or a part nucleation after nitridation. High-resolution transmission electron microscopy reveals approximately two monolayers if interlayer. In...
Abstract Although trimetylammonium-2-hydroxypropyl-hydroxyethylcellulose (QHEC) is a well-known polysaccharide material, some of its properties have not been previously studied in detail. Therefore, we applied combination multidimensional nuclear magnetic resonance (NMR) D 2 O on hydroxyethylcellulose (HEC) and HEC derivatives, size-exclusion chromatography with multi-angle laser light scattering (SEC-MALS) carbonate buffer at pH 10; while Fourier-transform infrared spectroscopy (FTIR), the...
Two InxAl1−xN layers were grown simultaneously on different substrates [sapphire (0001) and the Ga-polar GaN template], but under same reactor conditions, they employed to investigate mechanism of strain-driven compositional evolution. The resulting exhibit polarities layer sapphire is N-polar. Moreover, for two substrates, difference in degree relaxation was almost 100%, leading a large In-molar fraction 0.32. Incorporation In found be significantly influenced by strain imposed...
Surface condition before an insulator deposition is the key issue for preparation of reliable GaAs-based metal-oxide-semiconductor (MOS) devices. This study presents and properties InGaAs/GaAs MOS structures with a double-layer consisting oxygen-plasma oxide covered by Al2O3. The were oxidized during 75 s 150 s. Static measurements yielded saturation drain current ∼250 mA/mm at VG = 1 V. Capacitance showed improved performance in depletion region compared without insulator. Trapping effects...
High-frequency wireless communication in consumer, defense, and space applications heavily relies on the use of compound semiconductor amplifiers. Typically, X to Ka bands (∼8–40 GHz) are covered by GaN GaAs-based devices, respectively, desired output power. high-electron mobility transistors (HEMTs) provide an unprecedented ultralow-noise high-frequency operation even at cryogenic temperatures, critically important for high-fidelity amplification weak qubit states quantum computing....
Transparent conducting Al-doped ZnO films were grown by atomic layer deposition (ALD). Al-doping was introduced inserting 1 Al2O3 cycle per 28 cycles. The x-ray photoelectron spectroscopy showed that the density of Al donors is 2×1021–3×1021 cm−3, while Hall-effect measurements a ten times lower electron density. This low doping efficiency well-known inherent problem ALD method, and we wanted to explain its origin. We have found reduced traps at grain surface; however, effect too weak...
We report on local magnetization, tunnel diode oscillators, and specific-heat measurements in a series of Ba(Ni${}_{x}$Fe${}_{1\ensuremath{-}x}$)${}_{2}$As${}_{2}$ single crystals ($0.26\ensuremath{\le}x\ensuremath{\le}0.74$). show that the London penetration depth $\ensuremath{\lambda}(T)=\ensuremath{\lambda}(0)+\ensuremath{\Delta}\ensuremath{\lambda}(T)$ scales as $\ensuremath{\lambda}(0)\ensuremath{\propto}1/{T}_{c}^{0.85\ifmmode\pm\else\textpm\fi{}0.2}$,...
Semiconductor device temperature is challenging to measure; often IR thermography or electrical measurements are used which do not have a high enough spatial resolution for most of the current semiconductor technology detect sub-micron size hot spots. Thermal simulation therefore predict peak temperature. Limitations thermal simulations highlighted. Latest developments in actual measurement with including Raman Thermography, High Spatial Resolution Hyperspectral Quantum Rod Imaging, Atomic...
N‐polar InN/InAlN heterostructure growth and performance are studied on‐ off‐axis sapphire substrates misoriented toward the m or a plane by 4°. A high In molar fraction (0.57) in InAlN layer is chosen to reduce lattice mismatch. InN on on‐axis InAlN/sapphire system initiated with random island formation, which coalesce at ≈10 nm thickness smearing grain boundaries. contrast, sapphires, defined misorientation‐induced steps grains remain visible even after coalesces. The best electron...