Search results for "Heterostructure"
showing 10 items of 28 documents
High-Mobility, Wet-Transferred Graphene Grown by Chemical Vapor Deposition
2019
We report high room-temperature mobility in single layer graphene grown by Chemical Vapor Deposition (CVD) after wet transfer on SiO$_2$ and hexagonal boron nitride (hBN) encapsulation. By removing contaminations trapped at the interfaces between single-crystal graphene and hBN, we achieve mobilities up to$\sim70000cm^2 V^{-1} s^{-1}$ at room temperature and$\sim120000cm^2 V^{-1} s^{-1}$ at 9K. These are over twice those of previous wet transferred graphene and comparable to samples prepared by dry transfer. We also investigate the combined approach of thermal annealing and encapsulation in polycrystalline graphene, achieving room temperature mobilities$\sim30000 cm^2 V^{-1} s^{-1}$. These …
Facile synthesis of magnetically separable CoFe2O4/Ag2O/Ag2CO3 nanoheterostructures with high photocatalytic performance under visible light and enha…
2017
Riga Technical University supported the preparation of this manuscript from the Scientific Research Project Competition for Young Researchers No. ZP-2016/7. The authors wish to kindly acknowledge the financial support of HZB, Estonian Research Council (PUT1096, PUT735 and IUT2-25) and Estonian Centre of Excellence in Research Project “Advanced materials and high-technology devices for sustain-able energetics, sensorics and nanoelectronics” TK141 (2014–2020.4.01.15-0011).
Fast-Response Single-Nanowire Photodetector Based on ZnO/WS 2 Core/Shell Heterostructures
2018
This work was supported by the Latvian National Research Program IMIS2 and ISSP project for Students and Young Researchers Nr. SJZ/2016/6. S.P. is grateful to the ERA.Net RUS Plus WATERSPLIT project no. 237 for the financial support. S.V. is grateful for partial support by the Estonian Science Foundation grant PUT1689.
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…
Enhancing triplet superconductivity by the proximity to a singlet superconductor in oxide heterostructures
2016
We show how in principle a coherent coupling between two superconductors of opposite parity can be realized in a three-layer oxide heterostructure. Due to strong intraionic spin-orbit coupling in the middle layer, singlet Cooper pairs are converted into triplet ones and vice versa. This results in a large enhancement of the triplet superconductivity, persisting well above the native triplet critical temperature.
Codeposition of Fe 3 O 4 nanoparticles sandwiched between g-C3N4 and TiO2 nanosheets: Structure, characterization and high photocatalytic activity fo…
2019
Novel ternary nanocomposite photocatalysts based on g-C3N4 /Fe3O4 /TiO2 nanosheet were synthesized using simple solid combustion, hydrothermal and wetness impregnation methods. The g-C3N4 nanosheet (2D)/ Fe3O4 /TiO2 nanosheet (2D) triad-interface nanocomposite arranged in the form of Fe 3 O 4 nanoparticle was sandwiched and effectively dispersed on the surface between g-C3N4 and TiO2 nanosheets. The synthesized composites were characterized by some specific techniques such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electronic microscopy (FE-SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), specific su…
A facile way to synthesize noble metal free TiO2 based catalysts for glycerol photoreforming
2023
In this work anaerobic heterogeneous photocatalytic solar/UV light reforming of glycerol in aqueous media was performed with Pt-photodeposition and noble metal free modified TiO2 photocatalysts prepared through ball milling, a very simple and cheap coupled catalyst preparation method. Different amounts of Cu2O or 3% CuO were loaded on TiO2 using ball milling and during each run glycerol conversion, hydrogen and CO2 formed in the gas phase and 1,3-dihydroxyacetone (DHA) and glyceraldehyde (GA) in the liquid phase were determined. The results were compared with the aim to verify the effectiveness of Cu2O in replacing Pt. Using noble metal free photocatalysts, 33% glycerol conversion, 10.3% an…
Photoluminescence Enhancement by Band Alignment Engineering in MoS 2 /FePS 3 van der Waals Heterostructures
2022
Single-layer semiconducting transition metal dichalcogenides (2H-TMDs) display robust excitonic photoluminescence emission, which can be improved by controlled changes to the environment and the chemical potential of the material. However, a drastic emission quench has been generally observed when TMDs are stacked in van der Waals heterostructures, which often favor the nonradiative recombination of photocarriers. Herein, we achieve an enhancement of the photoluminescence of single-layer MoS2 on top of van der Waals FePS3. The optimal energy band alignment of this heterostructure preserves light emission of MoS2 against nonradiative interlayer recombination processes and favors the charge t…
Two-Dimensional Crystals and van der Waals Heterostructures based on Inorganic and Molecular Strongly Correlated Layered Materials
2021
“En resumen, toda obra grande es el fruto de la paciencia y de la perseverancia, combinadas con una atención orientada tenazmente durante meses y aun años hacia un objeto particular”. “In summary, all great work is the fruit of patience and perseverance, combined with tenacious concentration on a subject over a period of months or years”. Santiago Ramón y Cajal (Reglas y consejos sobre investigación científica. Madrid: Academia de Ciencias Exactas, Físicas y Naturales, 1897). The present Thesis constitutes a journey –a romance of many dimensions, quoting Edwin Abbot Abbot– from 3D to 2D and, hopefully (we let the curious Reader judge), “Through Flatland to Thoughtland” (citing, again, Abbot…
Hybrid heterostructures and materials based on transition metal dichalcogenides
2020
La irrupción de los nanomateriales en la vida moderna es un claro indicador del avance científico. El diseño de materiales a la carta permite establecer un control preciso sobre las propiedades finales de estos. El objetivo principal que ha motivado la presente Tesis es la combinación y funcionalización de láminas de MoS2 ultrafinas químicamente exfoliadas (ce-MoS2) con diferentes sistemas de base molecular. La Tesis se divide en los siguientes Capítulos: Capítulo I: En primer lugar, se introducen brevemente los nanomateriales. En segundo lugar, se describen los materiales bidimensionales (2D). A continuación, se detallan algunos aspectos generales de los dicalcogenuros de metales de transi…