Project leader Thomas Yager

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Research application No.


Ubiquitous sensing promises to revolutionise how devices interact with and respond to their surroundings including smart home automation, environmental monitoring and point-of-care medical diagnostics. The simultaneous combination of sensing systems are greater than the sum of their parts, as machine learning algorithms can discern correlations between parallel measurements. However, integrating multiple sensor functionalities within the same chip is a challenge for device integration. Graphene represents a uniquely versatile nanomaterial sensing platform which reduces cost and complexity of lab-on-chip systems whilst providing functionalities beyond silicon.

This research project aims to identify, investigate and overcome key bottlenecks towards realisation of a Universal lab-on chip graphene sensor. This significant nanoengineering challenge will require a combination of device design, nanofabrication, selective functionalisation and passivation. The development of novel nanoengineering methods and demonstration of multiple coexisting and parallel sensor functionalities can pave the way for the next generation of smart sensors and lab-on-chip technologies.


The project is implemented at the Institute of Solid State Physics of the University of Latvia from 01.01.2021. until 30.06.2023. The total cost of the project is 111 504.90 EUR.


Project progress


In the final stages of the project, the graphene sensor prototypes were further developed, characterized and tested. Combinations of geometrical device design, selective encapsulation and functionalization were employed to enable multiple functionalities. The three sensor types that were considered can be grouped as chemical, physical and photonic sensors. Physical and photonic sensors were found to have good compatibility, with similar requirements of passivated or stably controlled surfaces.

Electrochemical sensors have opposite operational requirements, and can involve the introduction of contaminating or perturbing molecules and species. However with suitable technological approaches, this third compatibility was also demonstrated. For example by selective encapsulation and passivation, and precision control of the location and flow of the targeted chemical species, taking inspiration from modern microfluidics engineering. Another encountered device engineering issue is a difference in the possible or planned reusability and lifetimes of the various sensor types. This is a particular issue for electrochemical, and especially biological, sensing where reusability and refreshing is more challenging than for the physical and photonic sensor devices.

For graphene biological sensing, collaboration continued with the Center for Physical Sciences and Technology FTMC (Lithuania). Graphene devices were functionalized with PBASE and antibodies, encased in PDMS microfluidic channels and analysed shifts in neutralizing gate voltage.

For molecular detection and thermal imaging, graphene hybrid metasurface sensors were developed together with RISE Research Institutes of Sweden and Halmstad University (Sweden). An open-access scientific article describing and analysing the graphene sensor devices was submitted; “Graphene hybrid metasurfaces for mid-infrared molecular sensors”.

In summary, the project has resulted in:

  • Two academic articles.
  • One technology prototype.
  • Several presentations of project results in leading international conferences and workshops, including Graphene Week 2022 (Germany), ISNTT (Japan), and SIO Sensors with Graphene (Sweden), EuroNanoLab.
  • Dissemination to diverse audiences of scientists, industry, and to the public.
  • Development of technical design databases, fabrication protocols and recipes.
  • International mobility visits and internships covering Sweden, Lithuania, and Estonia.
  • Hosted visits and tours from leading researchers from RISE Research Institutes of Sweden, Chalmers University of Technology (Sweden), University of Cambridge (UK)
  • New and strengthened international cooperation between ISSP UL and RISE Research Institutes of Sweden, Chalmers University of Technology (Sweden), University of Cambridge (UK), Halmstad University (Sweden), SenseairAB (Sweden), Center for Physical Sciences and Technology FTMC (Lithuania) and University of Tartu (Estonia), Photonics Sweden, Photonics Finland.
  • Submission of two follow-up research project proposals.

Participation in the Nordic Optics and Photonics conference industrial and academic committees for the Latvia region (top). Overview of the graphene sensor prototype fabrication and characterization (bottom).


A nanofabrication database was established for all users of the ISSP cleanroom facility. Fabrication recipes for electron beam lithography and production of graphene sensor devices was produced, and disseminated on the database.

During an internship to RISE Research Institutes of Sweden, the latest graphene universal sensor prototypes were tested at Electrum, Kista. A visit was made to the Printed Electronics Arena in Norrkoping, with discussions of synergistic approaches and potential collaboration opportunities.

An invited talk was given at the SIO Grafen “Sensors with graphene” workshop (Stockholm) to a mixed audience of academia and industry. Further details can be found in the CAMART news article:

SIO Grafen "Sensors with graphene" workshop (Stockholm)


Graphene based prototype sensor devices with multiple coexisting and parallel device architectures have been fabricated on 1cm substrates. Initial electronic measurement and characterisation of the devices confirmed the efficacy of the developed fabrication methods and technical designs

Results from the project were reported at Graphene Week 2022 - Europe's leading conference in Graphene and 2D Materials – including a poster presentation, networking and discussions with researchers and industry.


Electronic characterisation of a graphene prototype device


To strengthen the collaboration on graphene sensors for research and industrial applications, a number of international mobility activities were organised to Sweden, Estonia, and Lithuania.

In Kista, Stockholm, an internship was made with RISE Research Institutes of Sweden, involving nanoprocessing at the Electrum Laboratory clean room facility and optical and electronic characterisation of sensor devices at the Smart Hardware Department RISE. Meetings and discussions were held with academic and industrial partners, including a visit to SenseAir AB (pictured below). In Gothenburg, a seminar was given at Chalmers University of Technology, and the Nordic Nanolab User Meeting 2022 was attended, as well as further discussions with collaborating academics and industry.

A follow up visit was made to the University of Tartu, Physicum, where atomic force microscopy was used to characterise the nanoscale geometries of the sensor devices fabricated at the ISSP cleanroom. Additionally, a visit was also made to the Center for Physical Sciences and Technology (FTMC), Vilnius, where collaborative work has been initiated to solve issues towards graphene bio-sensors for COVID sensing applications.

Dr. Tom Yager (ISSP) and Dr. Qin Wang (RISE) (right) meeting with a team at SenseAir (left)


The first graphene based electronic devices have been fabricated at the ISSP cleanroom. Single atomic layers of graphene, grown by chemical vapor deposition, were patterned by oxygen plasma ashing and contacted with gold microelectrodes in a three-step electron beam lithography process.

Optical microscopy images of prototype electronic sensor devices showing patterned graphene (blue), metallic contacts (gold) and SiO2 substrate with removed graphene (red/pink).  Left: Opto-electronic wideband bow-tie antenna sensor. Right: Eight probe Hall bar electronic sensor. Atomic layer features and atomic defects within the graphene material are made visibile by an ‘LUT’ based real-time contrast enhancement method.

Fabrication of these devices was enabled by the development and optimisation of a number of processing procedures and recipes, including for example; electron beam lithography writing, dose-testing, stitching and alignment; alternative resists for improved lift off; plasma ashing recipes and selective etch rate characterisation; thermal evaporation materials and protocols; chemical processing recipes and timings.

A broad ranging interview with the post-doctoral researcher about the research project, institute and working in Latvia can be found here:


Graphene based sensors with multiple functionalities have been designed and are under process development for device fabrication at the ISSP cleanroom facility. Single atomic layer graphene, grown by chemical vapour deposition (CVD), is being used for these initial device demonstrations and process optimisation. Work towards graphene based biosensing applications continued, including a working visit to the Latvian Biomedical Research and Study Centre (BMC) and project planning with biological Senior Researcher Dr Arturs Abols.

Results from the project were reported in International Conferences, Meetings and Symposiums:
1. “Graphene based hybrid metasurfaces for mid-IR gas sensors”, at the International Symposium on Novel maTerials and quantum Technologies, ISNTT 2021, Japan. []
2. "Stitching, Proximity and Alignment", ROUME 2021, Raith, Germany.
3. “Infrared detector based on CVD graphene”, SIO Graphene Forum 2021, Sweden.
4. ISSP Scientific Seminar, “Electronic Sensors” 2021, Latvia.
5. Industrial partnership meeting organised between ISSP, Materize and Sensair AB, Sweden.

Wishing a happy and successful New Year 2022!


An article was published in the open-access journal MDPI Sensors "Time-Resolved FDTD and Experimental FTIR Study of Gold Micropatch Arrays for Wavelength-Selective Mid-Infrared Optical Coupling".  []

These results are part of an international collaborative effort between ISSP and researchers from RISE Research Institutes of Sweden, Halmstad University and SensairAB.  []

A working visit to the University of Tartu, Physicum, was arranged. In addition to visiting local laboratories, expertise was exchanged on the design, fabrication and characterisation of sensor nanodevices.

In an official Prime Ministerial visit to ISSP, nanosensor devices and their fabrication technologies were demonstrated. []

Two sensing conferences were attended:  MetaMaterials2021 and EuroSensors2021 (online).  []


Mid-infrared photodetector prototypes have been designed and fabricated. Gold nanostructure arrays, containing over 10 million individual micro-patches and nanogaps, were fabricated at the ISSP cleanroom by electron beam lithography (shown in picture, at different scales). The peak photoresponse wavelength of these structures can be directly tuned by the structure geometry. This approach attractive for applications in optical gas sensors for the detection of carbon dioxide or alcohol.

A manuscript based on this work has been submitted to a scientific journal.

At the Researchers Night 2021, the current project was presented in an approachable way for a general audience:

The EuroNanoLab consortium was also participated in by attending online workshops and presenting the nanofabrication capabilities of the ISSP clean room to the Lithography Experts Group. This collaboration is bringing together over 40 state-of-the-art academic nanofabrication centres across 14 countries, with the aim to build a Europe-wide nanofabrication infrastructure.  []

The image shows a sensor device prototype, where dense arrays of over 10 million gold nanostructures were fabricated on the surface of a 2cm x 2cm silicon chip.


To initiate the project, a literature review is being conducted on the topics of graphene sensor devices and fabrication technologies. In connection with this review, video conference meetings have been held with all project partners and collaborators.

In collaboration with the Research Institutes of Sweden (RISE) and Halmstad University we are designing and optimising infrared graphene based photodetectors, enhanced by coupled metal antenna elements with resonant absorption wavelengths suitable for environmental gas sensing.

An online scientific seminar hosted by ISSP UL was delivered, introducing the project plan and post-doctoral researcher. From this seminar, further connections and collaborations related to 2D sensor arrays were initiated.