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Electronic properties of new atomically thin semiconductors

English title Electronic properties of new atomically thin semiconductors
Applicant Morpurgo Alberto
Number 147607
Funding scheme Sinergia
Research institution Département de Physique de la Matière Condensée Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Condensed Matter Physics
Start/End 01.01.2014 - 31.12.2016
Approved amount 1'164'186.00
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Keywords (5)

atomic scale crystals; transition metal dichalcogenides; two-dimensional semiconductors; new materials for opto-electronics; semiconducting devices

Lay Summary (Italian)

Lead
Il progetto esplorera' le propieta' di una classe di materiali con spessore su scala atomica, i dicalcogenuri di metalli di transizione. Recenti ricerche hanno mostrato che per alcuni di questi materiali, quando lo spessore e' ridotto a scala atomica, le proprieta' differiscono in maniera importante da quelle di cristalli spessi. Estenderemo le ricerche a molti materiali dellla classe, per controllare le loro proprieta', e per utilizzarli nella fabbricazione di componenti opto-elettronici.
Lay summary

Titolo del progetto di ricerca

Propieta' elettroniche di nuovi semiconduttori con spessore atomico

In Sintesi

La scoperta del grafene ha mostrato che molti materiali possono essere ridotti in maniera controllata e preservando buona qualita' ad uno spessore di solamente qualche atomo. Su questa scala di spessori, le proprieta' elettriche e ottiche dei material cambiano in maniera significativa e possono acquisire nuove funzionalita'. Una classe di materiali che ha un enorme potenziale in questo contesto sono i dicalcogenuri di metalli di transizione, tra i quali molte decine di composti sono noti con una enorme varieta' di proprieta' elettroniche. Fino ad ora, solamente poichi di questi composti sono stati risotti a spessori atomici e solo alcune delle loro proprieta' sono state misurate, con risultati estremamente interessanti.

Soggeto e Obiettivo

Il nostro scopo e' multiplo. Innanzitutto, miriamo ad estendere significativamente il numero di materiali ed il tipo di proprieta' studiate. Inoltre, lavoreremo per migliorare il nostro controllo di questi materiali con spessore su scala atomica e per identificare nuovi processi di produzione. Infine esploreremo le possibilita' di utilizzare questi material per realizzare componenti opto-elettronici con nuove funzionalita'.

Contesto Socio- Scientifico

La nano-elettronica si sta sviluppando rapidamente e il controllo dei materiali su scala atomica sta diventando estremamente importante, e aumentera' ancora di importanza in futuro. Il nostro progetto mira a stabilire le basi scientifiche e tecnologiche per questi sviluppi.

 

 

Direct link to Lay Summary Last update: 20.11.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Dimensional crossover of the charge density wave transition in thin exfoliated VSe2
Arpad Pasztor, Scarfato Alessandro, Barreteau C{é}}line, Giannini Enrico, Renner Christoph (2017), Dimensional crossover of the charge density wave transition in thin exfoliated VSe2, in 2D Materials, 4(4), 041005-041005.
Note: Mechanical in situ exfoliation of van der Waals materials
Pasztor A., Scarfato A., Renner Ch. (2017), Note: Mechanical in situ exfoliation of van der Waals materials, in Review of Scientific Instruments, 88(7), 076104-1-076104-3.
Stripe and Short Range Order in the Charge Density Wave of 1T−CuxTiSe2
Novello A. M., Spera M., Scarfato A., Ubaldini A., Giannini E., Bowler D. R., Renner Ch. (2017), Stripe and Short Range Order in the Charge Density Wave of 1T−CuxTiSe2, in Physical Review Letters, 118(1), 017002-1-017002-5.
A robust molecular probe for Ångstrom-scale analytics in liquids
Nirmalraj Peter, Thompson Damien, Dimitrakopoulos Christos, Gotsmann Bernd, Dumcenco Dumitru, Kis Andras, Riel Heike (2016), A robust molecular probe for Ångstrom-scale analytics in liquids, in Nature Communications, 7, 12403-12403.
Direct observation of a long-range field effect from gate tuning of nonlocal conductivity
Wang L., Gutierrez-Lezama I., Barreteau C., Ki D.-K., Giannini E., Morpurgo A.F. (2016), Direct observation of a long-range field effect from gate tuning of nonlocal conductivity, in Physical Review Letters, 117, 176601.
Disorder engineering and conductivity dome in ReS2 with electrolyte gating
Ovchinnikov Dmitry, Gargiulo Fernando, Allain Adrien, Pasquier Diego José, Dumcenco Dumitru, Ho Ching-Hwa, Yazyev Oleg V., Kis Andras (2016), Disorder engineering and conductivity dome in ReS2 with electrolyte gating, in Nature Communications, 7, 12391-12391.
Electroluminescence from indirect gap semiconductor ReS2
Gutierrez-Lezama I., Reddy A., Ubrig N., Morpurgo A.F. (2016), Electroluminescence from indirect gap semiconductor ReS2, in 2D Materials, 3, 045016.
Fermi Arcs and Their Topological Character in the Candidate Type-II Weyl Semimetal MoTe2
Tamai A., Wu Q. S., Cucchi I., Bruno F. Y., Ricco S., Kim T. K., Hoesch M., Barreteau C., Giannini E., Besnard C., Soluyanov A. A., Baumberger F. (2016), Fermi Arcs and Their Topological Character in the Candidate Type-II Weyl Semimetal MoTe2, in PHYSICAL REVIEW X, 6(3), 031021.
Free-standing electronic character of monolayer MoS2 in van der Waals epitaxy
Kim HoKwon, Dumcenco Dumitru, Frégnaux Mathieu, Benayad Anass, Chen Ming-Wei, Kung Yen-Cheng, Kis Andras, Renault Olivier (2016), Free-standing electronic character of monolayer MoS2 in van der Waals epitaxy, in Physical Review B, 94(8), 081401-081401.
High-pressure melt growth and transport properties of SiP,SiAs,GeP,and GeAs 2D layered semiconductors
Barreteau C., Michon B., Besnard C., Giannini E. (2016), High-pressure melt growth and transport properties of SiP,SiAs,GeP,and GeAs 2D layered semiconductors, in J. Cryst. Growth , 443, 75.
Magnetoexcitons in large area CVD-grown monolayer MoS2 and MoSe2 on sapphire
Mitioglu A. A., Galkowski K., Surrente A., Klopotowski L., Dumcenco D., Kis A., Maude D. K., Plochocka P. (2016), Magnetoexcitons in large area CVD-grown monolayer MoS2 and MoSe2 on sapphire, in Physical Review B, 93(16), 165412-165412.
Observation of ionic Coulomb blockade in nanopores
Feng Jiandong, Liu Ke, Graf Michael, Dumcenco Dumitru, Kis Andras, Di Ventra Massimiliano, Radenovic Aleksandra (2016), Observation of ionic Coulomb blockade in nanopores, in Nature Materials, 15, 850-855.
Observation of large topologically trivial Fermi arcs in the candidate type-II Weyl semimetal WTe2
Bruno F. Y., Tamai A., Wu Q. S., Cucchi I., Barreteau C., de la Torre A., Walker S. McKeown, Ricco S., Wang Z., Kim T. K., Hoesch M., Shi M., Plumb N. C., Giannini E., Soluyanov A. A., Baumberger F. (2016), Observation of large topologically trivial Fermi arcs in the candidate type-II Weyl semimetal WTe2, in PHYSICAL REVIEW B, 94(12), 121112.
Single-layer MoS2 nanopores as nanopower generators
Feng Jiandong, Graf Michael, Liu Ke, Ovchinnikov Dmitry, Dumcenco Dumitru, Heiranian Mohammad, Nandigana Vishal, Aluru Narayana R., Kis Andras, Radenovic Aleksandra (2016), Single-layer MoS2 nanopores as nanopower generators, in Nature, 536, 197-200.
Ambipolar Light-Emitting Transistors on Chemical Vapor Deposited Monolayer MoS2
Ponomarev Evgeniy, Gutierrez-Lezama Ignacio, Ubrig Nicolas, Morpurgo Alberto F. (2015), Ambipolar Light-Emitting Transistors on Chemical Vapor Deposited Monolayer MoS2, in NANO LETTERS, 15(12), 8289-8294.
Direct fabrication of thin layer MoS2 field-effect nanoscale transistors by oxidation scanning probe lithography
Espinosa Francisco M., Ryu Yu K., Marinov Kolyo, Dumcenco Dumitru, Kis Andras, Garcia Ricardo (2015), Direct fabrication of thin layer MoS2 field-effect nanoscale transistors by oxidation scanning probe lithography, in APPLIED PHYSICS LETTERS, 106(10), 103503.
Electrical Transport Properties of Single-Layer WS2
Ovchinnikov Dmitry, Allain Adrien, Huang Ying-Sheng, Dumcenco Dumitru, Kis Andras (2015), Electrical Transport Properties of Single-Layer WS2, in ACS Nano, 8, 8174-8181.
Electrochemical Reaction in Single Layer MoS2: Nanopores Opened Atom by Atom
Feng J., Liu K., Graf M., Lihter M., Bulushev R. D., Dumcenco D., Alexander D. T. L., Krasnozhon D., Vuletic T., Kis A., Radenovic A. (2015), Electrochemical Reaction in Single Layer MoS2: Nanopores Opened Atom by Atom, in NANO LETTERS, 15(5), 3431-3438.
Electronic Properties of Transition-Metal Dichalcogenides
Kic Agnieszka, Heine Thomas, Kis Andras (2015), Electronic Properties of Transition-Metal Dichalcogenides, in MRS Bulletin, 40, 577.
Electrostatically Induced Superconductivity at the Surface of WS2
Jo Sanghyun, Costanzo Davide, Berger Helmuth, Morpurgo Alberto F. (2015), Electrostatically Induced Superconductivity at the Surface of WS2, in NANO LETTERS, 15(2), 1197-1202.
Identification of single nucleotides in MoS2 nanopores
Feng Jiandong, Liu Ke, Bulushev Roman D., Khlybov Sergey, Dumcenco Dumitru, Kis Andras, Radenovic Aleksandra (2015), Identification of single nucleotides in MoS2 nanopores, in NATURE NANOTECHNOLOGY, 10(12), 1070-1070.
Indirect-to-Direct Band Gap Crossover in Few-Layer MoTe2
Lezama Ignacio Gutierrez, Arora Ashish, Ubaldini Alberto, Barreteau Celine, Giannini Enrico, Potemski Marek, Morpurgo Alberto F. (2015), Indirect-to-Direct Band Gap Crossover in Few-Layer MoTe2, in NANO LETTERS, 15(4), 2336-2342.
Large-Area Epitaxial Mono layer MoS2
Dumcenco Dumitru, Ovchinnikov Dmitry, Marinov Kolyo, Lazic Predrag, Gibertini Marco, Marzari Nicola, Sanchez Oriol Lopez, Kung Yen-Cheng, Krasnozhon Daria, Chen Ming-Wei, Bertolazzi Simone, Gillet Philippe, Fontcuberta i Morral Anna, Radenovic Aleksandra, Kis Andras (2015), Large-Area Epitaxial Mono layer MoS2, in ACS NANO, 9(4), 4611-4620.
Large-Area MoS2 Grown Using H2S as the Sulphur Source
Dumcenco Dumitru, Ovchinnikov Dmitry, Lopez Sanchez Oriol, Gillet Philippe, Alexander Duncan, Lazar Sorin, Radenovic Aleksandra, Kis Andras (2015), Large-Area MoS2 Grown Using H2S as the Sulphur Source, in 2D Materials, 2, 044005.
Tuning magnetotransport in a compensated semimetal at the atomic scale
Wang Lin, Gutierrez-Lezama Ignacio, Barreteau Celine, Ubrig Nicolas, Giannini Enrico, Morpurgo Alberto F. (2015), Tuning magnetotransport in a compensated semimetal at the atomic scale, in NATURE COMMUNICATIONS, 6, 8892.
Improved chemical vapor transport growth of transition metal dichalcogenides
Ubaldini Alberto, Giannini Enrico (2014), Improved chemical vapor transport growth of transition metal dichalcogenides, in Journal of Crystal Growth, 401, 878.
Doping Nature of Native Defects in 1T-TiSe2
Hildebrand B., Didiot C., Novello A. M., Monney G., Scarfato A., Ubaldini A., Berger H., Bowler D. R., Renner C., Aebi P. (2014), Doping Nature of Native Defects in 1T-TiSe2, in PHYSICAL REVIEW LETTERS, 112(19), 197001.
Mono- and Bilayer WS2 Light-Emitting Transistors
Jo Sanghyun, Ubrig Nicolas, Berger Helmuth, Kuzmenko Alexey B., Morpurgo Alberto F. (2014), Mono- and Bilayer WS2 Light-Emitting Transistors, in NANO LETTERS, 14(4), 2019-2025.
Scanning photocurrent microscopy reveals electron-hole asymmetry in ionic liquid-gated WS2 transistors
Ubrig Nicolas, Jo Sanghyun, Berger Helmuth, Morpurgo Alberto F., Kuzmenko Alexey B. (2014), Scanning photocurrent microscopy reveals electron-hole asymmetry in ionic liquid-gated WS2 transistors, in APPLIED PHYSICS LETTERS, 104(17), 171112.
Surface transport and gap structure of exfoliated 2H-MoTe2 crystals
Gutierrez Lezama Ignacio, Ubaldini Alberto, Longobardi Marilena, Giannini Enrico, Renner Christoph, Kuzmenko Alexex, Morpurgo Alberto (2014), Surface transport and gap structure of exfoliated 2H-MoTe2 crystals, in 2D Materials, 1, 021002.
Electrostatically induced superconductivity at the surface of WS2
Jo Sanghyun, Costanzo Davide, Berger Helmuth, Morpurgo Alberto, Electrostatically induced superconductivity at the surface of WS2, in Nano Letters.
Gate-induced Superconductivity in atomically thin MoS2 Crystals
Costanzo D., Jo S., Berger H., Morpurgo A.F., Gate-induced Superconductivity in atomically thin MoS2 Crystals, in Nature Nanotechnology.

Collaboration

Group / person Country
Types of collaboration
Philipp Aebi, UniFR Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Depdeep Jena/University of Notre Dame United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. V. Falko/Lancaster University Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Exchange of personnel
David Bowler, UCL London Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Masahiro Ishigami/University of Cental Florida United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Gotthard Seifert/TU Dresden Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Thomas Heine/Jacobs University Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Grace Xing/University of Notre Dame United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Valeria Nicolosi/TCD Dublin Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
- Exchange of personnel
Prof. Forro/EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
2D Materials: from physics to engineering Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 23.11.2016 Grenoble, France Kis Andras;
European Conference on Nanofilms Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 19.10.2016 Bilbao, Spain Kis Andras;
Intel Ireland Research Conference 2016 Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 12.10.2016 Dublin, Ireland Kis Andras;
ESSDERC/ESSCIRC 2016 Talk given at a conference High-quality Synthetic 2D TMD Semiconductors 12.09.2016 Lausanne, Switzerland Kis Andras;
TNT 2016 Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 05.09.2016 Fribourg, Switzerland Kis Andras;
TNT2016 Talk given at a conference Exploring and engineering the electronic properties of 2D materials 05.09.2016 Fribourg, Switzerland Morpurgo Alberto;
Swiss Physical Society Annual Meeting Poster Nanoscale investigation of few monolayers thin exfoliated dichalcogenides 23.08.2016 Lugano, Switzerland Renner Christoph; Pasztor Arpad;
ETH-EPFL Summer school Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 22.08.2016 Zermatt, Switzerland Kis Andras;
ETH-EPFL Summer school Talk given at a conference Quantum transport through 2D transition metal dichalcogenides and their interfaces 22.08.2016 Zermatt, Switzerland Morpurgo Alberto;
Flatlands 2016 Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 05.07.2016 Bled, Slovenia Kis Andras;
E-MRS Spring meeting Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 02.05.2016 Lille, France Kis Andras;
Recent Developments in 2D Electron Systems Talk given at a conference Exploring and engineering the electronic properties of 2D materials 04.04.2016 Okinawa, Japan Morpurgo Alberto;
Israeli Materials Engineering Conference IMEC 17 Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 01.02.2016 Tel Aviv, Israel Kis Andras;
International Conference on Two-dimensional Layered Materials Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 07.01.2016 Hongkong, Hongkong Kis Andras;
IEDM Meeting Talk given at a conference High-frequency, Scaled MoS2 Transistors 07.12.2015 Washington, DC, United States of America Kis Andras;
MRS Fall Meeting Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 30.11.2015 Boston, United States of America Kis Andras;
Euro-Mediterranean Conference on Materials and Renewable Energies (EMCMRE) Talk given at a conference 2D Dichalcogenide Electronic Materials and Devices 02.11.2015 Marrakech, Morocco Kis Andras;
Ninth International Conference on Vortex Matter in Nanostructured Superconductors Poster Nanoscale investigation of few monolayers thin exfoliated dichalcogenides 12.09.2015 Rhodos, Greece Pasztor Arpad;
Vortex Matter in Nanostructured Superconductors Poster Nanoscale investigation of few monolayers thin exfoliated dichalcogenides 12.09.2015 Rhodes, Greece Pasztor Arpad;
Novel quantum materials and systems Talk given at a conference Quantum transport in 2D transition metal dichalcogenides 07.09.2015 Leiden, Netherlands Morpurgo Alberto;
Frontiers in Physics Talk given at a conference Quantum transport in 2D transition metal dichalcogenides 24.08.2015 Trieste, Italy Morpurgo Alberto;
Topical meeting on 2D transition metal dichalcogenides Talk given at a conference Optoelectronics with single layers WS2 28.06.2015 Castasegna, Switzerland Ubrig Nicolas;
International Frontiers in Quantum Materials and Devices Workshop Talk given at a conference MoS2 and Dichalcogenide-based Devices 21.05.2015 Cambridge, MA, United States of America Kis Andras;
E-MRS Spring Meeting Talk given at a conference MoS2 and Dichalcogenide-based Devices and Hybrid Heterostructures 11.05.2015 Lille, France Kis Andras;
Graphene 2015 Talk given at a conference MoS2 and dichalcogenide based devices and hybrid heterostructures 10.03.2015 Bilbao, Spain Kis Andras;
March meeting 2015 Talk given at a conference Electronics and atomic scale properties of defects and dopants in MoTe2 02.03.2015 San Antonio, TX, United States of America Renner Christoph;
APS March Meeting 2015 Talk given at a conference Van der Waals heterostructures for photodetection and light harvesting 02.03.2015 San Antonio, TX, United States of America Kis Andras;
ITN Spinograph Workshop Talk given at a conference MoS2 and dichalcogenide based devices and hybrid heterostructures 08.12.2014 Aachen, Germany Kis Andras;
Materials Research Society MRS Fall Meeting Talk given at a conference Chloride-Driven Chemical Vapor Transport for Crystal Growth of 2D Transition Metal Dichalcogenide 01.12.2014 Boston, United States of America Barreteau Céline;
Materials Research Society MRS Fall Meeting Talk given at a conference Single Crystal Growth and Characterization of 2D CDW Transition Metal Diselenides 01.12.2014 Boston, United States of America Barreteau Céline;
IMEC Workshop on beyound-CMOS electronics Talk given at a conference Single-Layer MoS2 – 2D Devices, Circuits and Heterostructures 16.10.2014 Leuven, Belgium Kis Andras;
ICN+T Conference Talk given at a conference Single-Layer MoS2 – 2D Devices, Circuits and Heterostructures 13.07.2014 Vail, Colorado, United States of America Kis Andras;
Flatlands 2014 Talk given at a conference Single-Layer MoS2 – 2D Devices, Circuits and Heterostructures 11.07.2014 Dublin, Ireland Kis Andras;
Nano Korea Talk given at a conference Single-layer MoS2 - 2D Devices and Circuits Beyond Graphene 02.07.2014 Seoul, Korean Republic (South Korea) Kis Andras;
Swiss Physical Society Meeting Talk given at a conference Opto-electronic properties of mono- and bi-layer WS2 30.06.2014 Fribourg, Switzerland Jo Sanghyun;
Graphene week Talk given at a conference Opto-electronic properties of mono- and bi-layer WS2 23.06.2014 Goteborg, Sweden Jo Sanghyun;
Iconsat Conference Talk given at a conference SINGLE-LAYER MOS2 - 2D DEVICES AND CIRCUITS BEYOND GRAPHENE 03.03.2014 Chandigarh, India Kis Andras;
TNT conference Talk given at a conference SINGLE-LAYER MOS2 - 2D DEVICES AND CIRCUITS BEYOND GRAPHENE 29.01.2014 Tokyo, Japan Kis Andras;
Thin-film transistors conference Talk given at a conference Single-layer MoS2 - electrical transport properties, devices and circuits 23.01.2014 Delft, Netherlands Kis Andras;


Self-organised

Title Date Place
1st EU Graphene Flagship-Japan Workshop 31.10.2015 Tokyo, Japan
1st EU Graphene Flagship - USA Workshop 22.04.2015 Arlington, United States of America

Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
Colloque de professeurs de gymnase Talk 05.11.2014 EPFL, Switzerland Kis Andras;


Communication with the public

Communication Title Media Place Year
Media relations: print media, online media L'électronique renaît en deux dimensions le Temps Western Switzerland 2016
New media (web, blogs, podcasts, news feeds etc.) Structural and Functional Properties of 2D Materials Explored Using AFM IOP Webinar International 2016

Associated projects

Number Title Start Funding scheme
169016 Electronic Phenomena at High Carrier Density in Field Effect Transistors 01.03.2017 Project funding (Div. I-III)
131960 Transport properties of surfaces and interfaces of organic semiconductors 01.03.2011 Project funding (Div. I-III)
157739 Setup for advanced transport characterisation of nanoelectronic devices 01.12.2014 R'EQUIP
132102 Electron microscopy of nanolayer devices 01.10.2010 Project funding (Div. I-III)
170728 Ionic liquid gating of novel materials at sub-Kelvin temperatures 01.01.2017 R'EQUIP
162612 Crystalline phases and structural defects in two-dimensional transition metal dichalcogenides 01.02.2016 Project funding (Div. I-III)
164015 Cryogen-free setup for characterisation of quantum dots based on 2D TMD materials 01.07.2016 R'EQUIP
144139 Ordered electronic phases in low dimensional superconductors 01.11.2012 Project funding (Div. I-III)
133777 Scanning probe microscopy and spectroscopy of nanoscale materials and devices 01.01.2011 R'EQUIP
121257 Graphene nano-structures for quantum electronics 01.09.2008 R'EQUIP
160084 Quantum transport in graphene nanostructures 01.05.2015 Project funding (Div. I-III)
138237 Tailoring 2d transition metal dichalcogenides for electronic applications 01.01.2012 Project funding (Div. I-III)
117404 Scanning Mott Microscopy to map the spin texture of manganites / Scanning tunneling microscope 01.07.2007 R'EQUIP
150079 Microscopic electronic processes in organic single-crystal transistors 01.03.2014 Project funding (Div. I-III)
161353 Optoelectronics of transition metal dichalcogenides: Physics and devices 01.01.2016 Ambizione
175822 Growth and electronic properties of novel 2D materials with unusual band structure evolution 01.08.2018 Project funding (Div. I-III)
153298 Optoelectronic devices based on 2D/3D heterojunctions 01.04.2014 Project funding (Div. I-III)

Abstract

The recent discovery of graphene has been drawing considerable attention to atomically thin crystalline materials with interesting electronic properties. These thin crystals can be extracted from layered, van der Waals bonded materials, where the absence of dangling bonds at the surface promotes chemical stability, enabling the realization of “defect-free” layers of atomic thickness. They are interesting for a variety of reasons. For instance, their electronic properties differ significantly from those of their bulk parent compounds, and -for metallic materials- these layers can be made as thin as the electrostatic screening length, allowing uniform modulation of the charge density by field-effect. The goal of this project is to explore -and learn to control- the electronic properties of two-dimensional, few-atoms-thick crystals of transition metal dichalcogenides (TMDs), with a focus on semiconducting systems. Layered TMDs include a multitude of compounds exhibiting a broad variety of electronic phenomena such as semiconducting behavior, semi-metallicity, superconductivity, and charge density waves. These systems have been extensively studied in their bulk form, but single- or few-layer systems remain virtually unexplored. Only very recent experiments -performed mainly on MoS2, the only of these materials easily available commercially- have shown that atomically thin MoS2 preserves outstanding quality, and exhibits new, fascinating properties. These results are attracting research groups all over the world to this area of research, which is at the forefront of our efforts in understanding and controlling matter at the atomic scale. This Sinergia project brings together three teams of established Swiss scientists to provide the expertise needed to perform a systematic study of the electronic properties of atomically thin TMDs. Our work will address (i) material synthesis, including crystal growth for exfoliation, and crystalline thin-film deposition, (ii) the realization of electronic devices and their use in the investigation of charge and thermal transport, and (iii) optical and scanning tunneling spectroscopy, and the study of opto-electronic processes. The combination of these activities will put us in an excellent position to make important contributions to the field. Having a strong material preparation activity will not only ensure the availability of all materials needed, but also that we will be able to explore how the electronic properties can be controlled at the level of synthesis, e.g. by making solid solutions or hetero-structures of different TMDs. Transport and opto-electronics experiments will allow us to probe complementary properties of single-layers (or few-layers) of different TMD crystals, and to perform comparative studies. Local probe imaging and tunneling spectroscopy will give direct information about size of band-gap, impurity atoms, and atomic scale structural defects. These experiments will also provide constant feedback on the quality of materials grown in the project. In semiconducting TMDs, a major focus will be on comparing the transport properties of valence and conduction bands -predicted theoretically to be very different in atomically thin crystals- on excitonic phenomena -also of interest for possible applications in photovoltaics or light detectors- and on thermal transport -relevant in relation to thermoelectric properties and to transistor stability issues. An exciting direction is the investigation of semi-metallic TMD compounds as a function of thickness: when made sufficiently thin, these materials can open a gap due to size quantization, turning themselves into technologically relevant small-gap semiconductors. The realization and study of the first hetero-interfaces and hetero-structures of TMDs will be another goal. Our work will also touch upon several other aspects, such as the recently demonstrated gate-induced superconductivity, or the theoretically predicted occurrence of magnetism in single layers of specific TMDs. As the exploration of materials at the atomic scale is a vast, emerging research field, we believe that our work has the concrete potential for the discovery of unexpected, exciting electronic phenomena, as well as for giving contributions to technology in different areas of applied electronics.
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