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Concept

Lacune (cristallographie)

Publications associées (31)

Interface connection of functionalized carbon nanotubes for efficient and stable perovskite solar cells

Mohammad Khaja Nazeeruddin, Jianxing Xia

The ionic defects of hetero-junction interfaces always attract and trap carriers via surface electrostatic forces, which are crucial for the efficiency and intrinsic stability of perovskite solar cells (PSCs). Herein, functionalized carbon nanotubes (CNTs) ...

Royal Society of Chemistry2023

Demonstrating and Unraveling a Controlled Nanometer-Scale Expansion of the Vacancy Defects in Graphene by CO2

Kumar Varoon Agrawal, Luis Francisco Villalobos Vazquez de la Parra, Kuang-Jung Hsu, Mojtaba Chevalier

A controlled manipulation of graphene edges and vacancies is desired for molecular separation, sensing and electronics applications. Unfortunately, available etching methods always lead to vacancy nucleation making it challenging to control etching. Herein ...

Wiley-VCH Verlag GmbH2022

Defect-induced magnetism in homoepitaxial SrTiO3

Mihai Adrian Ionescu, Daesung Park

Along with recent advancements in thin-film technologies, the engineering of complex transition metal oxide heterostructures offers the possibility of creating novel and tunable multifunctionalities. A representative complex oxide is the perovskite stronti ...

AIP Publishing2022

Systematic design of millisecond gasification reactor for the incorporation of gas-sieving nanopores in single-layer graphene

Kumar Varoon Agrawal, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Shaoxian Li, Kuang-Jung Hsu

Etching an ensemble of vacancy defects (nanopores) in single-layer graphene (SLG) to obtain a high density of nanopores with an effective size that enables high-performance gas sieving is challenging. This is because nanopore nucleation and expansion are u ...

2021

Imaging Nonradiative Point Defects Buried in Quantum Wells Using Cathodoluminescence

Nicolas Grandjean, Jean-François Carlin, Raphaël Butté, Duncan Thomas Lindsay Alexander, Wei Liu, Wei Liu, Thomas Fjord Kjaersgaard Weatherley

Crystallographic point defects (PDs) can dramatically decrease the efficiency of optoelectronic semiconductor devices, many of which are based on quantum well (QW) heterostructures. However, spatially resolving individual nonradiative PDs buried in such QW ...

AMER CHEMICAL SOC2021

Millisecond lattice gasification for high-density CO2- and O2-sieving nanopores in single-layer graphene

Emad Oveisi, Kumar Varoon Agrawal, Mounir Driss Mensi, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Mostapha Dakhchoune, Shaoxian Li, Deepu Joseph Babu, Marina Micari

Etching single-layer graphene to incorporate a high pore density with sub-angstrom precision in molecular differentiation is critical to realize the promising high-flux separation of similar-sized gas molecules, e.g., CO2 from N2. However, rapid etching ki ...

2021

Bottom-up synthesis of graphene films hosting atom-thick molecular-sieving apertures

Emad Oveisi, Kumar Varoon Agrawal, Kangning Zhao, Victor Carle Adrien Boureau, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Mostapha Dakhchoune, Shaoxian Li, Kuang-Jung Hsu, Cédric Karel J Van Goethem, Yueqing Shen, Mina Moradi

Incorporation of a high density of molecular-sieving nanopores in the graphene lattice by the bottom-up synthesis is highly attractive for high-performance membranes. Herein, we achieve this by a controlled synthesis of nanocrystalline graphene where incom ...

National Academy of Sciences2021

Effects of quantum-well indium content on deep defects and reliability of InGaN/GaN light-emitting diodes with under layer

Nicolas Grandjean, Jean-François Carlin, Camille Haller

We investigate the density of defects and the degradation rate in InGaN light-emitting diodes having identical dislocation density and epitaxial structure, but different indium content in the quantum well (QW; 12%, 16%, 20%). Our results, based on combined ...

IOP PUBLISHING LTD2021

Catalyzing Bond-Dissociation in Graphene via Alkali-Iodide Molecules

Klaus Kern, Stephan Rauschenbach, Sabine Abb, Sven Alexander Szilagyi, Hannah Julia Ochner

Atomic design of a 2D-material such as graphene can be substantially influenced by etching, deliberately induced in a transmission electron microscope. It is achieved primarily by overcoming the threshold energy for defect formation by controlling the kine ...

WILEY-V C H VERLAG GMBH2021

Identifying and Tracking Defects in Dynamic Supramolecular Polymers

Michele Ceriotti, Piero Gasparotto

A central paradigm of self-assembly is to create ordered structures starting from molecular monomers that spontaneously recognize and interact with each other via noncovalent interactions. In recent years, great efforts have been directed toward perfecting ...

AMER CHEMICAL SOC2020

Optoelectronic and magnetic properties induced by atomic defects in two-dimensional semiconductors

Alessio Scavuzzo

Two-dimensional (2D) materials have attracted increasing attention over the last decade owing to their remarkable mechanical, electrical and optical properties. Following the groundbreaking discovery of graphene, a plethora of other atomically-thin materia ...

EPFL2020

Characterizing crystalline defects in single nanoparticles from angular correlations of single-shot diffracted X-rays

Christoph Bostedt

Characterizing and controlling the uniformity of nanoparticles is crucial for their application in science and technology because crystalline defects in the nanoparticles strongly affect their unique properties. Recently, ultra-short and ultra-bright X-ray ...

INT UNION CRYSTALLOGRAPHY2020

Nature of native atomic defects in ZrTe5 and their impact on the low-energy electronic structure

Helmuth Berger, Oleg Yazyev, Ana Akrap, Shengnan Zhang

Over the past decades, investigations of the anomalous low-energy electronic properties of ZrTe5 have reached a wide array of conclusions. An open question is the growth method's impact on the stoichiometry of ZrTe5 samples, especially given the very small ...

AMER PHYSICAL SOC2020

Atomic-scale defects in the two-dimensional ferromagnet CrI3 from first principles

Michele Pizzochero

The family of atomically thin magnets holds great promise for a number of prospective applications in magneto-optoelectronics, with CrI3 arguably being its most prototypical member. However, the formation of defects in this system remains unexplored to dat ...

IOP PUBLISHING LTD2020

Giant anomalous Hall effect in quasi-two-dimensional layered antiferromagnet Co1/3NbS2

László Forró, Helmuth Berger, Edoardo Martino

The discovery of the anomalous Hall effect (AHE) in bulk metallic antiferromagnets (AFMs) motivates the search of the same phenomenon in two-dimensional (2D) systems, where a quantized anomalous Hall conductance can, in principle, be observed. Here we pres ...

AMER PHYSICAL SOC2020

Band Gap of Atomically Precise Graphene Nanoribbons as a Function of Ribbon Length and Termination

Christoph Leopold Talirz

We study the band gap of finite NA=7 armchair graphene nanoribbons (7-AGNRs) on Au(111) through scanning tunneling microscopy/spectroscopy combined with density functional theory calculations. The band gap of 7-AGNRs with lengths of 8 nm and more is conver ...

WILEY-V C H VERLAG GMBH2019

High-permeance polymer-functionalized single-layer graphene membranes that surpass the postcombustion carbon capture target

Emad Oveisi, Kumar Varoon Agrawal, Mounir Driss Mensi, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Guangwei He, Mojtaba Chevalier, Jing Zhao

Membrane-based postcombustion carbon capture can reduce the capture penalty in comparison to absorbent-based separation. To realize this, high-performance membranes are urgently needed with a CO2 permeance exceeding 1000 gas permeation units or GPU, and a ...

2019

Self-consistent site-dependent DFT plus U study of stoichiometric and defective SrMnO3

Nicola Marzari, Iurii Timrov, Matteo Cococcioni, Ulrich Aschauer

We propose a self-consistent site-dependent Hubbard U approach for density functional theory (DFT)+U calculations of defects in complex transition metal oxides, using Hubbard parameters computed via linear response theory. The formation of a defect locally ...

AMER PHYSICAL SOC2019

Template-assisted grown III-V semiconductor nanowires: A transmission electron microscopy study

Nicolas Bologna

III-V semiconductor nanowires are, due to their unique properties, one of the most promising nanostructures developed in the last decades. However, the realization of commercial devices made of III-V nanowires, such as transistors and solar cells, has not ...

EPFL2019

Hydrogen sieving from intrinsic defects of benzene-derived single-layer graphene

Kumar Varoon Agrawal, Mostapha Dakhchoune, Shiqi Huang, Mojtaba Chevalier, Jing Zhao, Mina Moradi

Single-layer graphene films, crystallized by chemical vapor deposition, host a low density of vacancy defects that are attractive for the size-sieving of molecules. The size and the density of such defects are a function of the growth temperature and the c ...

2019

Publications associées (31)

Systematic design of millisecond gasification reactor for the incorporation of gas-sieving nanopores in single-layer graphene

Kumar Varoon Agrawal, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Shaoxian Li, Kuang-Jung Hsu

2021

Effects of quantum-well indium content on deep defects and reliability of InGaN/GaN light-emitting diodes with under layer

Nicolas Grandjean, Jean-François Carlin, Camille Haller

IOP PUBLISHING LTD2021

High-permeance polymer-functionalized single-layer graphene membranes that surpass the postcombustion carbon capture target

Emad Oveisi, Kumar Varoon Agrawal, Mounir Driss Mensi, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Guangwei He, Mojtaba Chevalier, Jing Zhao

2019