Two dimensional III-VI semiconductors and graphene-hybrid heterostructures
Lead Research Organisation:
University of Nottingham
Department Name: Sch of Physics & Astronomy
Abstract
The isolation of single-atomic layer graphene has led to a surge of interest in other layered crystals with strong in-plane bonds and weak, van der Waals-like, interlayer coupling. A variety of two-dimensional (2D) crystals have been investigated, including large band gap insulators and semiconductors with smaller band gaps such as transition metal dichalcogenides. Interest in these systems is motivated partly by the need to combine them with graphene to create field effect transistors with high on-off switching ratios. More importantly, heterostructures made by stacking different 2D crystals on top of each other provide a platform for creating new artificial crystals with potential for discoveries and applications.
The possibility of making van der Waals heterostructures has been demonstrated experimentally only for a few 2D crystals. However, some of the currently available 2D layers are unstable under ambient conditions, and those that are stable offer only limited functionalities, i.e. low carrier mobility, weak optical emission/absorption, band gaps that cannot be tuned, etc. In a recent series of pilot experiments, we have demonstrated that nanoflakes of the III-VI layer compound, InSe, with thickness between 5 and 20 nanometers, have a "thickness-tuneable" direct energy gap and a sufficiently high chemical stability to allow us to combine them with graphene and related layer compounds to make heterostructures with novel electrical and optical properties. The main goal of this project is to develop graphene-hybrid heterostructures based on this novel class of two-dimensional (2D) III-VI van der Waals crystals. This group of semiconductors will enrich the current "library" of 2D crystals by overcoming limitations of currently available 2D layers and by offering a versatile range of electronic and optical properties. From the growth and fabrication of new systems to the demonstration of prototype devices, including vertical tunnel transistors and optical-enhanced-microcavity LEDs, our project will provide a platform for scientific investigations and will contribute to the technology push required to create new routes to device miniaturization, fast-electronics, sensing and photonics. There is great potential for further growth of all these sectors as the fabrication of 2D systems improves and as new properties are discovered and implemented in functional devices.
The possibility of making van der Waals heterostructures has been demonstrated experimentally only for a few 2D crystals. However, some of the currently available 2D layers are unstable under ambient conditions, and those that are stable offer only limited functionalities, i.e. low carrier mobility, weak optical emission/absorption, band gaps that cannot be tuned, etc. In a recent series of pilot experiments, we have demonstrated that nanoflakes of the III-VI layer compound, InSe, with thickness between 5 and 20 nanometers, have a "thickness-tuneable" direct energy gap and a sufficiently high chemical stability to allow us to combine them with graphene and related layer compounds to make heterostructures with novel electrical and optical properties. The main goal of this project is to develop graphene-hybrid heterostructures based on this novel class of two-dimensional (2D) III-VI van der Waals crystals. This group of semiconductors will enrich the current "library" of 2D crystals by overcoming limitations of currently available 2D layers and by offering a versatile range of electronic and optical properties. From the growth and fabrication of new systems to the demonstration of prototype devices, including vertical tunnel transistors and optical-enhanced-microcavity LEDs, our project will provide a platform for scientific investigations and will contribute to the technology push required to create new routes to device miniaturization, fast-electronics, sensing and photonics. There is great potential for further growth of all these sectors as the fabrication of 2D systems improves and as new properties are discovered and implemented in functional devices.
Planned Impact
From the fabrication and growth of new heterostructures to the demonstration of prototype devices, including transistors, and optical-microcavity-enhanced LEDs and photodetectors, our project will provide a platform for scientific investigations and will contribute to the technology required to create new routes to device miniaturization, fast-electronics, sensing, miniaturised LEDs/photodetectors, and graphene-based integrated optoelectronic circuits.
To maximize this impact, we will promote the adoption of our methods of fabrication, new 2D layers and graphene-hybrid systems to collaborators within the EU GRAPHENE Flagship and interested parties in academia and industry. This will be facilitated by our links to leading international research groups, facilities and industry. In particular, in 2011 Nottingham established a partnership with e2v Technologies ltd, a UK company with over 1500 employees and turnover exceeding £200M (http://www.e2v.com). e2v Technologies ltd. has established a centre within the School of Physics and Astronomy at Nottingham, which manufactures semiconductor devices. e2v Technologies ltd. will work with our team to assess the technical and economic feasibility of a commercial product and provide expertise in identifying routes to technology transfer. The vertical tunnel transistor based on 2D III-VI layers provides an innovative device architecture that will enable access to fast electron speeds at room temperature ; photonic applications of the 2D III-VI layers are also particularly attractive due to the potential to access a wide spectral range across the visible and near-infrared range, and will be explored in collaboration with Helia Photonics ltd, a company specializing in optical coatings for micro-optics and light emitting semiconductor devices. We have also links with the UK National Graphene Institute funded by the EPSRC and Bluestone Global Tech, which has established their European production plant in Manchester. Relationships with industry are central to the operation of the Institute and some of the world's biggest and most influential companies are already working with it on applications of graphene.
The proposed activities align with plans to establish at Nottingham the first Molecular Beam Epitaxy dual-chamber system in the UK for the synthesis of graphene/boron nitride heterostructures (operational in summer 2014). This is part of over £50M UK investment to establish the UK as a graphene research and technology 'hub'. Our work on new 2D van der Waals crystals will both benefit from this new national initiative and will contribute to its expansion by enabling the fabrication of new graphene-hybrid structures.
In addition to the impact arising from research outputs, we highlight the output of 2 post-doctoral researchers and 3 PhD students who will contribute to a new generation of talent and leaders in key scientific areas and whose training will be enhanced through their participation in this project.
In summary, our project will generate transformational impact on science and technology; maintain and enhance the UK leadership in key scientific areas and training; leverage impact through the alignment and collaboration with national and international programmes.
To maximize this impact, we will promote the adoption of our methods of fabrication, new 2D layers and graphene-hybrid systems to collaborators within the EU GRAPHENE Flagship and interested parties in academia and industry. This will be facilitated by our links to leading international research groups, facilities and industry. In particular, in 2011 Nottingham established a partnership with e2v Technologies ltd, a UK company with over 1500 employees and turnover exceeding £200M (http://www.e2v.com). e2v Technologies ltd. has established a centre within the School of Physics and Astronomy at Nottingham, which manufactures semiconductor devices. e2v Technologies ltd. will work with our team to assess the technical and economic feasibility of a commercial product and provide expertise in identifying routes to technology transfer. The vertical tunnel transistor based on 2D III-VI layers provides an innovative device architecture that will enable access to fast electron speeds at room temperature ; photonic applications of the 2D III-VI layers are also particularly attractive due to the potential to access a wide spectral range across the visible and near-infrared range, and will be explored in collaboration with Helia Photonics ltd, a company specializing in optical coatings for micro-optics and light emitting semiconductor devices. We have also links with the UK National Graphene Institute funded by the EPSRC and Bluestone Global Tech, which has established their European production plant in Manchester. Relationships with industry are central to the operation of the Institute and some of the world's biggest and most influential companies are already working with it on applications of graphene.
The proposed activities align with plans to establish at Nottingham the first Molecular Beam Epitaxy dual-chamber system in the UK for the synthesis of graphene/boron nitride heterostructures (operational in summer 2014). This is part of over £50M UK investment to establish the UK as a graphene research and technology 'hub'. Our work on new 2D van der Waals crystals will both benefit from this new national initiative and will contribute to its expansion by enabling the fabrication of new graphene-hybrid structures.
In addition to the impact arising from research outputs, we highlight the output of 2 post-doctoral researchers and 3 PhD students who will contribute to a new generation of talent and leaders in key scientific areas and whose training will be enhanced through their participation in this project.
In summary, our project will generate transformational impact on science and technology; maintain and enhance the UK leadership in key scientific areas and training; leverage impact through the alignment and collaboration with national and international programmes.
Organisations
- University of Nottingham (Lead Research Organisation)
- University of Manchester (Collaboration, Project Partner)
- Chinese Academy of Sciences (Collaboration)
- University of Zurich (Collaboration)
- National Physical Laboratory (Collaboration)
- Helia Photonics (United Kingdom) (Project Partner)
- Teledyne e2v (United Kingdom) (Project Partner)
- University of Oxford (Project Partner)
- National Institute for Materials Science (Project Partner)
- European Union (Project Partner)
- National Academy of Sciences of Ukraine (Project Partner)
- Bluestone Global Tech Limited (Project Partner)
Publications
Lv Q
(2020)
Interlayer Band-to-Band Tunneling and Negative Differential Resistance in van der Waals BP/InSe Field-Effect Transistors
in Advanced Functional Materials
Makarovsky O
(2017)
Enhancing optoelectronic properties of SiC-grown graphene by a surface layer of colloidal quantum dots
in 2D Materials
Mazumder D
(2020)
Enhanced Optical Emission from 2D InSe Bent onto Si-Pillars
in Advanced Optical Materials
Moro F
(2018)
Room Temperature Uniaxial Magnetic Anisotropy Induced By Fe-Islands in the InSe Semiconductor Van Der Waals Crystal
in Advanced Science
Mudd GW
(2015)
High broad-band photoresponsivity of mechanically formed InSe-graphene van der Waals heterostructures.
in Advanced materials (Deerfield Beach, Fla.)
Mudd GW
(2016)
The direct-to-indirect band gap crossover in two-dimensional van der Waals Indium Selenide crystals.
in Scientific reports
Svatek S
(2015)
Graphene-InSe-graphene van der Waals heterostructures
in Journal of Physics: Conference Series
Turyanska L
(2015)
Ligand-Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene-Quantum Dot Transistor
in Advanced Electronic Materials
Turyanska L
(2017)
Mobility enhancement of CVD graphene by spatially correlated charges
in 2D Materials
Velichko A
(2016)
Highly-mismatched InAs/InSe heterojunction diodes
in Applied Physics Letters
Description | We have demonstrated that two-dimensional metal chalcogenide materials have unprecedented physical properties, e.g. high electron mobility and strong photosensitivity. Furthermore, their properties are compatible with and complement the two most established vdW crystals, hexagonal boron nitride (hBN) and graphene, thus enabling us to fabricate a new class of functional devices "beyond graphene", including high mobility field effect transistors, sensitive photodetectors and photovoltaic junctions. Our prototype devices have optical and electrical properties that are already comparable or superior to those of conventional semiconductors (e.g. Si and III-Vs). To realise their full potential for a viable commercial technology, we are developing scalable and reliable fabrication methods, and techniques to probe and modify surface and heterostructure interfaces. We have identified InSe as an optimal choice for device fabrication due to its optical stability and electronic properties. The InSe flakes are optically active at room temperature, in the technologically important near-infrared spectral range between 1 and 0.7 micron, and their near-band edge optical emission undergoes a strong blue-shift to higher photon energies with decreasing thickness. The quantum shift was observed in p- and n-type InSe, and for deposition of the layers on various substrates, including graphene. The direct-to-indirect band gap crossover and the quantum shift of the energy band gap were investigated by density functional theory (DFT) and magneto-optical studies. We have exploited the broad-band transparency of graphene, the favourable energy band line-up of graphene with n-type InSe nanosheets, and the electronic properties of InSe to create graphene-InSe-graphene heterostructures with high photosensitivity at room temperature. In these devices an InSe nanosheet and two graphene layers are "laterally" or "vertically" stacked. For the device fabrication, we have used different methods that employ exfoliated graphene and CVD-graphene. The latter differs from those previously used to form vertical devices with exfoliated graphene; it could be extended to other material systems and device architectures, and offers a route to device scalability. We have investigated and grown successfully different crystal phases of In-Se and demonstrated electronic, vibrational and optical properties distinct from those of other compounds. The successful growth of thin films with thicknesses down to a few layers, represent an important step-forward towards the development of van der Waals 2D crystals and scalable processes for 2D technologies. We have reported on a "giant" quantum Hall effect plateau in a graphene-based field effect transistor where graphene is capped by a layer of the van der Waals crystal InSe. The "giant" quantum Hall effect plateau arises from the close alignment of the conduction band edge of InSe with the Dirac point of graphene. This feature enables the magnetic field and electric field effect-induced transfer of charge carriers between InSe and the degenerate Landau level states of the adjacent graphene layer, which is coupled by a van der Waals hetero-interface to the InSe. |
Exploitation Route | Our research results were shared with members of the research community through conference presentations and our involvement in the EU graphene flagship (2014-20), stimulating further activities. |
Sectors | Chemicals Digital/Communication/Information Technologies (including Software) Education Electronics Energy |
Description | The research has led to the establishment of a bespoke facility (EPI2SEM) for the EPItaxial growth and In-situ analysis of 2SEM, funded by an EPSRC Strategic Equipment Award [£2.94M, EP/T019018/1, 2020-24]. Following the installation of EPI2SEM at Nottingham in 2021-22, Patanè and her team developed high-quality 2SEM. EPI2SEM is now a hub for 2SEM development via a pump-priming scheme of the EPSRC National Epitaxy Facility for the provision of 2SEM to the UK community (2023-28). This has stimulated new partnerships worldwide, including with the Defence Science and Technology Laboratory (Dstl) via an Industrial Cooperative Award in Science&Technology (2022-26) and a project on UV-C sensors and sources for optical communication (2022-25). |
First Year Of Impact | 2022 |
Sector | Education,Electronics,Energy,Security and Diplomacy |
Impact Types | Cultural |
Description | EPI2SEM: EPItaxial growth and in-situ analysis of 2-dimensional SEMiconductors |
Amount | £2,938,943 (GBP) |
Funding ID | EP/T019018/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 02/2020 |
End | 01/2023 |
Description | EPSRC Industrial CASE (ICASE) |
Amount | £118,562 (GBP) |
Funding ID | Voucher Award 220003 |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Sector | Public |
Country | United Kingdom |
Start | 09/2022 |
End | 09/2026 |
Description | EU graphene flagship (Horizon 2020) |
Amount | € 512,000 (EUR) |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 03/2016 |
End | 03/2020 |
Description | EU-ITN, Postgraduate Research on Dilute Metamorphic Nanostructures and Metamaterials in Semiconductor Photonics "PROMIS" |
Amount | € 262,000 (EUR) |
Funding ID | 641899 |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 01/2015 |
End | 12/2019 |
Description | European Union's Horizon 2020 research and innovation programme Graphene Flagship Core 3 |
Amount | € 100,000 (EUR) |
Organisation | European Commission H2020 |
Sector | Public |
Country | Belgium |
Start | 03/2020 |
End | 03/2023 |
Description | Feasibility Study into Novel Concepts for a UV Communications System |
Amount | £98,000 (GBP) |
Funding ID | PA2260 |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Sector | Public |
Country | United Kingdom |
Start | 06/2022 |
End | 02/2023 |
Description | Novel Concepts for a UV Communication System |
Amount | £800,000 (GBP) |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Sector | Public |
Country | United Kingdom |
Start | 06/2023 |
End | 03/2025 |
Description | Partnership with the Institute of Semiconductors (Chinese Academy of Sciences) |
Organisation | Chinese Academy of Sciences |
Country | China |
Sector | Public |
PI Contribution | Exchange of samples, joint experiments and PhD students. |
Collaborator Contribution | Exchange of samples, joint experiments and PhD students. |
Impact | - Joint publications (listed with other outputs) - International Fellowship awarded to Prof. Patane (6 months visit) - Honorary professorship to Prof. Patane - Joint 4-year PhD program: University of Nottingham and Institute of Semiconductors (CAS) |
Start Year | 2018 |
Description | Partnerships with members of the EU Graphene Flagship (Horizon 2020) |
Organisation | National Physical Laboratory |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Our research on metal chalcogenide van der Waals crystals initiated new research activities and received funding within Horizon 2020. Collaborations include work on device fabrication and quantum transport in InSe, and magnetic force microscopy studies of magnetic InSe with the University of Manchester, ETH-Zurich and the National Physical Laboratory (UK). Nottingham provided materials to these partners and took part in all discussions/paper writing. |
Collaborator Contribution | The University of Manchester and ETH-Zurich provided device fabrication and experimental transport studies of InSe. The NPL assisted with the magnetic force microscopy studies of magnetic InSe. |
Impact | The collaboration has led to joint publications, as listed in the list of publications. |
Start Year | 2015 |
Description | Partnerships with members of the EU Graphene Flagship (Horizon 2020) |
Organisation | University of Manchester |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Our research on metal chalcogenide van der Waals crystals initiated new research activities and received funding within Horizon 2020. Collaborations include work on device fabrication and quantum transport in InSe, and magnetic force microscopy studies of magnetic InSe with the University of Manchester, ETH-Zurich and the National Physical Laboratory (UK). Nottingham provided materials to these partners and took part in all discussions/paper writing. |
Collaborator Contribution | The University of Manchester and ETH-Zurich provided device fabrication and experimental transport studies of InSe. The NPL assisted with the magnetic force microscopy studies of magnetic InSe. |
Impact | The collaboration has led to joint publications, as listed in the list of publications. |
Start Year | 2015 |
Description | Partnerships with members of the EU Graphene Flagship (Horizon 2020) |
Organisation | University of Zurich |
Country | Switzerland |
Sector | Academic/University |
PI Contribution | Our research on metal chalcogenide van der Waals crystals initiated new research activities and received funding within Horizon 2020. Collaborations include work on device fabrication and quantum transport in InSe, and magnetic force microscopy studies of magnetic InSe with the University of Manchester, ETH-Zurich and the National Physical Laboratory (UK). Nottingham provided materials to these partners and took part in all discussions/paper writing. |
Collaborator Contribution | The University of Manchester and ETH-Zurich provided device fabrication and experimental transport studies of InSe. The NPL assisted with the magnetic force microscopy studies of magnetic InSe. |
Impact | The collaboration has led to joint publications, as listed in the list of publications. |
Start Year | 2015 |
Description | "Indium Selenide: from nanosheets to heterostructures" Flagship-NSF Workshop '2D Materials, heterostructures and devices' Manchester, UK 10-12 October 2016 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Supporters |
Results and Impact | Flagship-NSF Workshop '2D Materials, heterostructures and devices' to engage the US community in research activities |
Year(s) Of Engagement Activity | 2016 |
Description | "Novel routes to 2D Science and Technologies" CDT Summer Conference on the Science and Technology of Graphene and related Materials, Cheshire, UK 27-30 June 2016 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Postgraduate students |
Results and Impact | Centre of Doctoral Training: Summer Conference on the Science and Technology of Graphene and related Materials, Cheshire, UK 27-30 June 2016 |
Year(s) Of Engagement Activity | 2016 |
Description | Conference-Invited Talk-InSe rediscovered: a van der Waals crystal for electronics and optoelectronics, US-EU Graphene Flagship Symposium Arlington, US 23-25 October, 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | Plan for research application with other teams |
Year(s) Of Engagement Activity | 2017 |
Description | Conference-invited talk- Hybrid quantum systems based on two-dimensional van der Waals crystals, International Symposium on Hybrid Quantum Systems (HQS2017) Miyagi-Zao, Japan, 10-13 Sept, 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | scientific discussions |
Year(s) Of Engagement Activity | 2017 |
Description | Conference-invited talk- Novel two-dimensional van der Waals crystals and heterostructures, The First International Semiconductor Conference for Global Challenges, Nanjing, China 16-19 July 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Plans for further research |
Year(s) Of Engagement Activity | 2017 |
Description | InSe rediscovered: a van der Waals crystal for electronics and optoelectronics, EP2DS-22 / MSS-18 (22nd International Conference on Conference-Invited Talk-Electronic Properties of Two Dimensional Systems and 18th International Conference on Modulated Semiconductor Structures) Pennsylvania State University, US July 31- Aug4, 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Plans made for future related activity |
Year(s) Of Engagement Activity | 2017 |
Description | Invited talk at EDISON2015, Salamanca, Spain 2015 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Report on new research findings on InSe at The 19th International Conference on Electron Dynamics in Semiconductor" Salamanca, Spain 29 June-2 July 2015 |
Year(s) Of Engagement Activity | 2015 |
Description | Seminar - InSe rediscovered: a van der Waals crystal for electronics and optoelectronics, Lausanne, EPFL, Switzerland, 7 July 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | Plans made for future related activity |
Year(s) Of Engagement Activity | 2017 |
Description | Seminar- InSe rediscovered: a van der Waals crystal for electronics and optoelectronics NPL, Teddington 4 April 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Industry/Business |
Results and Impact | Joint research activity |
Year(s) Of Engagement Activity | 2017 |
Description | Seminar-InSe rediscovered: a van der Waals crystal for electronics and optoelectronics, Dresden, HZDR, Germany, 30 June 2017 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | Plans future related activity |
Year(s) Of Engagement Activity | 2017 |