Integrated graphene - based sensor devices via scalable microfabrication process development based on graphene - metal multilayer deposition

Lead Research Organisation: Imperial College London
Department Name: Materials

Abstract

In spite of its challenging properties, the utilization of graphene for technical applications still demands considerable efforts in developing dedicated processing methods, which have a potential to be adapted and finally utilized for industrial scale device manufacturing. Among the processes which have been investigated so far, chemical vapour deposition of graphene on copper, where copper acts as a catalyst to facilitate the growth of single layered graphene - appears to be one the most promising approaches. Although extensively studied, there are issues with this process related to quality, reproducibility and yield, which are connected to the lack of control of the interface between copper and graphene. Within the process, which we will be able to tackle these issues in a more controllable way by a combined in-situ deposition system, where copper and other possible metals are deposited within one vacuum system together with the graphene CVD, i.e without exposing the sample to an ambient environment. Like for 2D Ga-Al-As semiconductor heterostructures, the control of the interfaces on an atomic length scale by means of an in-situ multilayer deposition process is expected to be the pathway which will enable the ultilization of graphene's unqiue properties within manufacturable device structures.

In spite of this potential, we feel the full integration of graphene into CMOS technology, although being extremely challenging on the long term - still has a very long way to go and may even be impossible without fundamentally different processing approaches. However, sensor technologies as a whole are mostly based on hybrid solutions, where the sensor itself - even chip based in some cases - is still separated from the CMOS digital electronic by flip chip, wire bonding or simple by conventional wiring. A widely used example of high indutrial impact are piezoelectric sensors, where the high processing temperature of the lead-zirconium-titanate ceramics are incompatible with CMOS processing conditions.

Based on this philosophy, we believe that the in-situ growing approach for metal-graphene multilayers, as envisaged to be developed within this project, will enable a significant improvement of existing sensor concepts and the realization and manufacturing of new sensor concepts. Based on the expertise of our scientific partners within Imperial College and NPL and our associated partners from industry, we will focus on biosensor applications, where graphene - as carbon based material - is particularly challenging as bio-interface. As - from the point of view of process technology -the most simple approach, graphene coated copper electrodes will have a potential for radiofrequency - microwave - terahertz biosensor, where copper will outperform gold due to lower conduction losses and graphene provides the interface to the biomolecules and cells. As a second step on a scale of increasing complexity of process technology, we believe that a sacrificial layer process for arbitrary shaped free standing graphene membranes and (sub)micro scale flexural beam is a realistic development goal. This technology will enable the development of arrays of nanomechanical sensors, based on the exceptional mechanical properties of graphene. Apart from sensor applications, graphene- based NEMS structures are challenging objects for the refinement and exploration of metrology for nanotechnology and biology, as being pursued by our collaborators from NPL.

The recently discovered confined plasmon-polariton excitations - originating from the unique electronic properties of graphene - are currently one of the hottest topic within the graphene research community. We believe, that the tailored free standing structures we will be able to manufacture with this deposition kit, will pave the way to explore and finally utilize this unique optical - infrared properties of graphene for novel sensor applications.

Planned Impact

The proposal aims to develop a wafer scalable deposition technology for graphene based multilayers for industrial scale manufacturing of integrated sensor devices. As such, we are clearly addressing the most promising technological approach based on a combination of metal electron beam deposition and plasma enhanced chemical vapour deposition within one ultrahigh vacuum system, which is expected to enable the realization and finally the commercialization of graphene-based sensor products. This will open up the huge potential of graphene, in terms of its unique optical, electrical, and mechanical properties, for exploitation, putting the UK in a competitive position at a time when major international funding drives (e.g. Horizon 2020) have started to target graphene. Within the current work, we are targeting specifically transition towards the biosensors market, with its huge growth potential in areas such as healthcare, point-of-care monitoring, and environmental sensing.

In partnership with Agilent Technologies, which is currently expanding their life science business, and world class biosensor groups at universities within the UK and Europe, we will explore the potential of graphene-based biosensors based on the 3 most established sensor concepts: rf impedance spectroscopy, micro/nanomechanical sensor structures and optical / IR sensors based on plasmon-polariton excitations.

Beyond these established sensor approaches, we will investigate planar microwave transmission line microwave resonators based on functionalized graphene-coated patterned copper structures for possible sensor applications in partnership with EMISENS / Link Microtek ltd, based on the PI's successful development of the bottle scanner EMILI 2. Moreover, with NPL as partner we intend to look into graphene-based NEMS technology for applications in metrology.

It is very important that the deposition cluster system, which will be purchased by means of the requested funding, and the processes which will be developed and optimized for graphene films, free standing structures and devices, are carefully assessed in term of reproducibility, yield and scalability throughout the project, in order to establish impact on industrial manufacturing processes early on in the project.

During and after this project, we will utilize our unique technology to develop dedicated research proposals addressing specific biosensor applications - together with our academic and industry partners.

Publications

10 25 50
 
Description • A new method contact-free assessment of the quality of large-area graphene has been established
• A new test assembly for comprehensive testing of the THz field effect in graphene was developed and tested.
• Graphene transfer was optimized with regards to the fabrication of sensor arrays
• Dynamics of graphene reflectivity when coupled to plasmonic nanoparticle arrays investigated
- Conditions for growth graphene - strontium titanate heterostructures were explored.
- A new method for substrate assessment with regards to preparation of highly reproducible electronic devices was developed.
- A self-gated graphene transistor based on a graphene-lanthanum aluminate heterstructure was demonstrated for the first time.
- A graphene biosensor for exosome detection was demonstrated and a graphene biosensor for cardiovascular disease detection was developed and optimized.
- A process for wafer scale graphene device fabrication was developed.
Exploitation Route use of microwave graphene characterization technique and Raman spectriscopy by other research groups and industry.

Within the Department of Materials and other users at Imperial College, the graphene deposition kit is the working horse for high quality graphene. A number of exciting results were achieved, one article was recently accepted by Nature (update in due course).

Currently a research proposal about graphene microwave sensors is under preparation and will be submitted to EPSRC soon.
Sectors Chemicals,Education,Electronics,Healthcare,Security and Diplomacy

 
Description The graphene deposition system is currently utilized as one of the enabling machines for our progressing work on graphene biosensors and graphene solar cells. We recently were awarded by EPSRC for a proposal about cancer cell detection based on graphene-aluminium nitride heterostructures (EP/P02985X/1), our graphene deposition techniques is being used to build the thin film structures for the sensors. As most important recent success, our graphene films were used by our partners in Germany to develop biosensors for the detection of cardiovascular desease biomarkers, the results were recently published as a joint publication in "Biosensors and Bioelectronics". In fact, the achieved high manufacturing yields for their biosensors result from the high reproducibility of our graphene process. Moreover, the system has been used for student training within the Departments of Materials and Physics. The graphene system has been optimized and refined over the years and is the backbone for running activities related to graphene biosensors. The mm wave vector network analyser being purchased from this grant has been used in a variety of different project related to terahertz sensing. The equipment has triggered the launch of Imperial's Centre for THz Science and Engineering, https://www.imperial.ac.uk/terahertz , the annual report of the center, which can be downloaded from this website, is the documentation of the use of this equipment by academic partners and partners from industry. The Raman system being purchase from this grant is widely used by staff from the departments of Physics and Materials, primarely for 2D matrials. It has become an inevitable piece of kit for our ongoing research.
First Year Of Impact 2017
Sector Education,Electronics,Environment,Healthcare
Impact Types Societal,Economic

 
Description responsive mode Healthcare Technolgies
Amount £1,200,000 (GBP)
Funding ID EP/P02985X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2018 
End 12/2020
 
Description Advanced graphene device characterization 
Organisation National Physical Laboratory
Country United Kingdom 
Sector Academic/University 
PI Contribution graphene deposition and device fabrication
Collaborator Contribution Kelvin probe microscopy, microwave near field microscopy
Impact mots recent joint publications: Adabi M, Lischner J, Hanham SM, Shaforost O, Wang R, Mihai, Hao L, Petrov P, Klein Nclose, Microwave study of field-effect devices based on graphene/aluminum nitride/graphene structures, Scientific Reports, ISSN: 2045-2322 (accepted) Gajewski K, Goniszewski S, Szumska A, Moczala M, Kunicki P, Gallop J, Klein N, Hao L, Gotszalk Tclose, 2016, Raman Spectroscopy and Kelvin Probe Force Microscopy characteristics of the CVD suspended graphene, DIAMOND AND RELATED MATERIALS, Vol: 64, Pages: 27-33, ISSN: 0925-9635 Goniszewski S, Adabi M, Shaforost O, Hanham SM, Hao L, Klein Nclose, 2016, Correlation of p-doping in CVD Graphene with Substrate Surface Charges, SCIENTIFIC REPORTS, Vol: 6, ISSN: 2045-2322 Gregory AP, Blackburn JF, Lees K, Clarke RN, Hodgetts TE, Hanham SM, Klein Nclose, 2016, Measurement of the permittivity and loss of high-loss a Near-Field Scanning Microwave Microscope, ULTRAMICROSCOPY, Vol: 161, Pages: 137-145, ISSN: 0304-3991 Goniszewski S, Gallop J, Adabi M, Gajewski K, Shaforost O, Klein N, Sierakowski A, Chen J, Chen Y, Gotszalk T, Hao Lclose, 2015, Self-supporting graphene films and their applications, IET CIRCUITS DEVICES & SYSTEMS, Vol: 9, Pages: 420-427, ISSN: 1751-858X
Start Year 2013
 
Description Combined accoustic / electromagnetic biosensors, graphene biosensors 
Organisation Imperial College London
Department Department of Chemical Engineering
Country United Kingdom 
Sector Academic/University 
PI Contribution - development of methodology and chip development for microwave detection of single cells - development of biofunctionalization of graphene layers - preparation of large area CVD layers for biuosensors
Collaborator Contribution - development of cell sorting by surface accoustic waves. - development of biofunctionalization of graphene layers
Impact - joint research proposal under preparation: combined accoustic / electromagnetic microfluidic device for marker free circulating tumoiur cell detection. - collaboration between postdocs and PhD students from both groups. - joint publication currently under reviews
Start Year 2016
 
Description Scanning transmission electron microscopy (STEM) on functionalized graphene 
Organisation Karlsruhe Institute of Technology
Country Germany 
Sector Academic/University 
PI Contribution We provide samples of our graphene / functionalized graphene
Collaborator Contribution The group hold the record for high resolution of STEM. High resolution scanning transmission electron microscopy reveals the distribution of the self organized linker molecules on the graphene surface.
Impact STEM still in progress
Start Year 2018
 
Description micromechanical graphene sensors 
Organisation University of Wroclaw
Country Poland 
Sector Academic/University 
PI Contribution Free standing Graphene sensor structures, aluminium nitride thin films
Collaborator Contribution etched silicon microstructures for graphene sensor preparation, tunneling microscopy and surface analysis, piezoelectric measurements with atomic force microscopy.
Impact one joint publication: Gajewski K, Goniszewski S, Szumska A, Moczala M, Kunicki P, Gallop J, Klein N, Hao L, Gotszalk Tclose, 2016, Raman Spectroscopy and Kelvin Probe Force Microscopy characteristics of the CVD suspended graphene, DIAMOND AND RELATED MATERIALS, Vol: 64, Pages: 27-33, ISSN: 0925-9635 bilateral exchange of staff joint PhD supervision
Start Year 2014