Search query: Carrier scattering, mobilities and electrostatic potential in mono-, bi- and tri-layer graphenes

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abstract: Ferrites are a large class of oxides containing Fe3+ and at least another metal cation that have been investigated for and applied to a wide variety of fields ranging from mature technologies like circuitry, permanent magnets, magnetic recording and microwave devices to the most recent developments in areas like bioimaging, gas sensing and photocatalysis. In the last respect, although ferrites have been less studied than other types of semiconductors, they present interesting properties such as visible light absorption, tuneable optoelectronic properties and high chemical and photochemical stability. The versatility of their chemical composition and of their crystallographic structure opened a playground for developing new catalysts with enhanced efficiency. This article reviews the recent development of the application of ferrites to photoassisted processes for environmental remediation and for the synthesis of solar fuels. Applications in the photocatalytic degradation of pollutants in water and air, photo Fenton, and solar fuels production, via photocatalytic and photoelectrochemical water splitting and CO2 reduction, are reviewed paying special attention to the relationships between the physico chemical characteristics of the ferrite materials and their photoactivated performance.
author_names: Patricia Garcia-Munoz

Fernando Fresno

Victor A de la Pena O'Shea

Nicolas Keller
title: Ferrite Materials for Photoassisted Environmental and Solar Fuels Applications
venue: Topics in Current Chemistry
year: 2019

abstract: Design and modification of interfaces, always a critical issue for semiconductor devices, has become a primary tool to harness the full potential of halide perovskite (HaP) based optoelectronics, including photovoltaics and light emitting diodes. In particular, the outstanding improvements in HaP solar cell performance and stability can be primarily ascribed to a careful choice of the interfacial layout in the layer stack. In this review, we describe the unique challenges and opportunities of these approaches (section 1) For this purpose, we first elucidate the basic physical and chemical properties of the exposed HaP thin film and crystal surfaces, including topics such as surface termination, surface reactivity, and electronic structure (section 2) This is followed by discussing experimental results on the energetic alignment processes at the interfaces between the HaP and transport and buffer layers. This section includes understandings reached as well as commonly proposed and applied models, especially the often questionable validity of vacuum level alignment, the importance of interface dipoles, and band bending as the result of interface formation (section 3) We follow this by elaborating on the impact of the interface formation on device performance, considering effects such as chemical reactions and surface passivation on interface energetics and stability. On the basis of these concepts, we propose a roadmap for the next steps in interfacial design for HaP semiconductors (section 4) emphasizing the importance of achieving control over the interface energetics and chemistry (i.e. reactivity) to allow predictive power for tailored interface optimization.
author_names: Philip Schulz

David Cahen

Antoine Kahn
title: Halide Perovskites: Is It All about the Interfaces?
venue: Chemical reviews
year: 2019

abstract: The current research in graphene spintronics strives for achieving a long spin lifetime, and efficient spin injection and detection in graphene. In this article, we review how hexagonal boron nitride (hBN) has evolved as a crucial substrate, as an encapsulation layer, and as a tunnel barrier for manipulation and control of spin lifetimes and spin injection/detection polarizations in graphene spin valve devices. First, we give an overview of the challenges due to conventional SiO2/Si substrate for spin transport in graphene followed by the progress made in hBN based graphene heterostructures. Then we discuss in detail the shortcomings and developments in using conventional oxide tunnel barriers for spin injection into graphene followed by introducing the recent advancements in using the crystalline single/bi/tri layer hBN tunnel barriers for an improved spin injection and detection which also can facilitate two terminal spin valve and Hanle measurements at room temperature, and are of technological importance. A special case of bias induced spin polarization of contacts with exfoliated and chemical vapour deposition (CVD) grown hBN tunnel barriers is also discussed. Further, we give our perspectives on utilizing graphene hBN heterostructures for future developments in graphene spintronics.
author_names: M Gurram

S Omar

Bart Jan van Wees
title: Electrical spin injection, transport, and detection in graphene hexagonal boron nitride van der Waals heterostructures progress and perspectives
year: 2018

abstract: Research pertaining to conductive polymers has gained significant traction in recent years, and their applications range from optoelectronics to material science. For all intents and purposes, conductive polymers can be described as Nobel Prize winning materials, given that their discoverers were awarded the Nobel Prize in Chemistry in 2000. In this review, we seek to describe the chemical forms and functionalities of the main types of conductive polymers, as well as their synthesis methods. We also present an in depth analysis of composite conductive polymers that contain various nanomaterials such as graphene, fullerene, carbon nanotubes, and paramagnetic metal ions. Natural polymers such as collagen, chitosan, fibroin, and hydrogel that are structurally modified for them to be conductive are also briefly touched upon. Finally, we expound on the plethora of biomedical applications that harbor the potential to be revolutionized by conductive polymers, with a particular focus on tissue engineering, regenerative medicine, and biosensors.
author_names: Toktam Nezakati

Amelia Seifalian

Alexander Marcus Seifalian
title: Conductive Polymers: Opportunities and Challenges in Biomedical Applications.
venue: Chemical reviews
year: 2018

abstract: Two dimensional (2D) materials have attracted tremendous research interest since the breakthrough of graphene. Their unique optical, electronic, and mechanical properties hold great potential for harnessing them as key components in novel applications for electronics and optoelectronics. Their atomic thickness and exposed huge surface even make them highly designable and manipulable, leading to the extensive application potentials. What's more, after acquiring the qualification for being the candidate for next generation devices, the assembly of 2D materials monomers into mass or ordered structure is also of great importance, which will determine their ultimate industrialization. By designing the monomers and regulating their assembling behavior, the exploration of 2D materials toward the next generation circuits can be spectacularly achieved. In this review, we will first overview the emerging 2D materials and then offer a clear guideline of varied physical and chemical strategies for tuning their properties. Furthermore, assembly strategies of 2D materials will also be included. Finally, challenges and outlooks in this promising field are featured on the basis of its current progress.
author_names: Mengqi Zeng

Yao Xiao

Jinxin Liu

Kena Yang

Lei Fu
title: Exploring Two Dimensional Materials toward the Next Generation Circuits: From Monomer Design to Assembly Control.
venue: Chemical reviews
year: 2018

abstract: The discovery of two dimensional (2D) materials with unique electronic, superior optoelectronic, or intrinsic magnetic order has triggered worldwide interest in the fields of material science, condensed matter physics, and device physics. Vertically stacking 2D materials with distinct electronic and optical as well as magnetic properties enables the creation of a large variety of van der Waals heterostructures. The diverse properties of the vertical heterostructures open unprecedented opportunities for various kinds of device applications, e.g. vertical field effect transistors, ultrasensitive infrared photodetectors, spin filtering devices, and so on, which are inaccessible in conventional material heterostructures. Here, the current status of vertical heterostructure device applications in vertical transistors, infrared photodetectors, and spintronic memory/transistors is reviewed. The relevant challenges for achieving high performance devices are presented. An outlook into the future development of vertical heterostructure devices with integrated electronic and optoelectronic as well as spintronic functionalities is also provided.
author_names: Shi-Jun Liang

Bin Cheng

Xinyi Cui

Feng Miao
title: Van der Waals Heterostructures for High Performance Device Applications: Challenges and Opportunities.
venue: Advanced materials
year: 2019

abstract: The chemistry of graphene oxide is discussed in this critical review. Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure. Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene like materials, is also discussed. This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references)
author_names: Daniel R Dreyer

Sungjin Park

Christopher W Bielawski

Rodney S Ruoff
title: The chemistry of graphene oxide.
venue: Chemical Society reviews
year: 2010

abstract: Additive manufacturing (AM) alias 3D printing translates computer aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography) powder bed fusion (SLS) material and binder jetting (inkjet and aerosol 3D printing) sheet lamination (LOM) extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting) and 3D bioprinting. The range of polymers used in AM encompasses thermoplastics, thermosets, elastomers, hydrogels, functional polymers, polymer blends, composites, and biological systems. Aspects of polymer design, additives, and processing parameters as they relate to enhancing build speed and improving accuracy, functionality, surface finish, stability, mechanical properties, and porosity are addressed. Selected applications demonstrate how polymer based AM is being exploited in lightweight engineering, architecture, food processing, optics, energy technology, dentistry, drug delivery, and personalized medicine. Unparalleled by metals and ceramics, polymer based AM plays a key role in the emerging AM of advanced multifunctional and multimaterial systems including living biological systems as well as life like synthetic systems.
author_names: Samuel Clark Ligon

Robert Liska

Jurgen Stampfl

Matthias Gurr

Rolf Mulhaupt
title: Polymers for 3D Printing and Customized Additive Manufacturing
venue: Chemical reviews
year: 2017

abstract: The current research in graphene spintronics strives for achieving a long spin lifetime, and efficient spin injection and detection in graphene. In this article, we review how hexagonal boron nitride (hBN) has evolved as a crucial substrate, as an encapsulation layer, and as a tunnel barrier for manipulation and control of spin lifetimes and spin injection/detection polarizations in graphene spin valve devices. First, we give an overview of the challenges due to conventional SiO2/Si substrate for spin transport in graphene followed by the progress made in hBN based graphene heterostructures. Then we discuss in detail the shortcomings and developments in using conventional oxide tunnel barriers for spin injection into graphene followed by introducing the recent advancements in using the crystalline single/bi/tri layer hBN tunnel barriers for an improved spin injection and detection which also can facilitate two terminal spin valve and Hanle measurements at room temperature, and are of technological importance. A special case of bias induced spin polarization of contacts with exfoliated and chemical vapour deposition (CVD) grown hBN tunnel barriers is also discussed. Further, we give our perspectives on utilizing graphene hBN heterostructures for future developments in graphene spintronics.
title: University of Groningen Spin transport in graphene hexagonal boron nitride van der Waals heterostructures
year: 2018

abstract: Sustainable societal and economic development relies on novel nanotechnologies that offer maximum efficiency at minimal environmental cost. Yet, it is very challenging to apply green chemistry approaches across the entire life cycle of nanotech products, from design and nanomaterial synthesis to utilization and disposal. Recently, novel, efficient methods based on nonequilibrium reactive plasma chemistries that minimize the process steps and dramatically reduce the use of expensive and hazardous reagents have been applied to low cost natural and waste sources to produce value added nanomaterials with a wide range of applications. This review discusses the distinctive effects of nonequilibrium reactive chemistries and how these effects can aid and advance the integration of sustainable chemistry into each stage of nanotech product life. Examples of the use of enabling plasma based technologies in sustainable production and degradation of nanotech products are discussed from selection of precursors derived from natural resources and their conversion into functional building units, to methods for green synthesis of useful naturally degradable carbon based nanomaterials, to device operation and eventual disintegration into naturally degradable yet potentially reusable byproducts.
author_names: Kateryna Bazaka

Mohan V Jacob

Kostya Ken Ostrikov
title: Sustainable Life Cycles of Natural Precursor Derived Nanocarbons.
venue: Chemical reviews
year: 2016