TECHNOLOGIES OF THIN FILMS RESEARCH GROUP – group leader Prof. Kęstutis Arlauskas
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Arlauskas Kęstutis, Dr. (HP) Saulėtekio av. 3, A 312 85 223 4544 |
About
Development of optoelectronic devices promotes the search for new materials such as inorganic, organic, hybrid, and composite thin layers, as well as one-dimensional and two-dimensional structures. The capabilities of lithography have almost reached their limits; therefore, one possible future solution is to find technologies and materials that allow the development of self-forming nanostructures for the next generation electronic and optoelectronic devices. I order to solve these problems, it is necessary to develop technologies of formation of thin layers and interlayers.
Research
- Searching for the new technologies of formation of thin layers and structures.
- Studies of influence of the layer deposition technologies on the spectrum of internal energy states and their distribution in the layers, interlayer and structures.
- Searching for technologies for self-forming nanostructures for optoelectronic devices and/or X-ray sensors.
The group performs
- Formation of layers of inorganic, organic, hybrid and composite materials using various technological approaches;
- Development of new devices based on synthetic diamond, graphene and other sophisticated carbon or silicon layers;
- Searching for new technologies to form layers of inorganic, organic and composite origin suitable for high energy particle and X-ray sensors;
- Optimization of the layer formation technologies to obtain desirable morphology, optical and electrical properties of the layers;
- Experimental research and theoretical modelling of the influence of different types of electromagnetic radiation on the formation of layers and structures.
Equipment
- The in-house equipment allows the formation of the layers from solutions, thermal and vacuum thermal evaporation and CVD plasma technology.
- Thin-layer structure studies are performed using optical and atomic force microscopes as well as a small-angle X-ray spectrometer.
- Electrical and photoelectric properties are investigated by TOF, CELIV and other methods.
Equipment for thin film deposition
Keywords
Thin film technologies; spin coating; thermal melting; thermal vacuum evaporation; plasma deposition; inorganic materials; organic materials; hybrid materials; composites; multilayer structures.
Employees
Prof., dr. Kęstutis Arlauskas (Head) - physicist (over 200 publications);
Doc., Dr. Andrius Poškus - physicist (17 publications);
Dr. Gytis Sliaužys - physicist (17 publications);
Dr. Romaldas Purlys - physicist (23 publications, 2 patents);
Dr. Tomas Grigaitis - physicist (5 publications);
Doctoral student Rokas Dobužinskas - physicist (4 publications);
Giedrius Juška - physicist (3 publications)
CHARGE TRANSFEREE IN DISORDERED MATERIALS RESEARCH GROUP – group leader dr. Kristijonas Genevičius
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Genevičius Kristijonas, Dr. Saulėtekio av. 3, A 304 85 223 4553 |
About
In today’s electronics amorphous materials are mainly used in copying-printing machines and liquid crystal display pixel drivers. The biggest advantages of the amorphous materials are cheap deposition techniques, flexibility of the layers and suitability for large area devices, such as solar cells electronic paper, RFID tags, large area light emitting surfaces, etc. Investigations of the charge carrier’s transport properties are very important for developing new electronic devices. Our research group focuses in such investigations and development of the new experimental techniques as well as in sample and device preparation.
Research areas
Formation of the organic layers and devices from solution
Estimation of drift mobility, recombination mechanism and lifetime of charge carriers
Characterisation of organic solar cells and field effect transistors
Modelling of charge carriers transport
Development of the new electrical and photo-electrical techniques for the investigation of charge carrier’s transport
Projects
2015-2018 Research Council of Lithuania, project “Investigation of the Charge Carriers Transport Features in Thin Multilayered Hybrid Structures“, leader dr. K. Genevičius
2012-2015m. FP7-PEOPLE-2011-ITN, project „ESTABLIS – Ensuring Stability in Organic Solar Cells“, leader of group from Vilnius University prof. G. Juška.
2011-2015m. Research Council of Lithuania, project “Influence of Nano-Morphology on Charge Carrier Dynamics”, leader prof. G. Juška.
Resources
Sample and device preparation. Fume hoods and all necessary equipment for cleaning of the substrates and preparation of the solutions, glovebox for the sample preparation under inert atmosphere and equipment for the thermal evaporation under vacuum.
Experimental setup
Complete setups for time of flight, double injection, space charge limited current and charge carriers extraction by linearly increasing voltages techniques (Nd:YAG laser, tuneable wavelength laser, cryostats, memory oscilloscopes, etc.). Solar simulator with two channels voltage-current source meter for solar cells and field effect characterisation.
Staff
Dr. Kristijonas Genevičius
technology, experiment
FTMC, A304
8 5 223 4553
Prof. Gytis Juška
analytical calculations, experiment
FTMC, A305
8 5 223 4554
Dr. Nerijus Nekrašas
numerical modelling, experiment
FTMC, A301
Dr. Mindaugas Viliūnas
numerical modelling, electronics
FTMC, A333
8 5 223 4563
PhD stud. Andrius Aukštuolis
technology, experiment
FTMC, A301
PhD. student Romualdas Jonas Čepas
technology, experiment
FTMC, A310
PHOTOPHYSICS OF ORGANIC MATERIALS RESEARCH GROUP – group leader Prof. Vygintas Jankauskas
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Jankauskas Vygintas, Dr. Saulėtekio av. 3, A 308, A 328 85 223 4548 |
About
We are exploring new and promising organic materials for solar cells, light emitting diodes, thin film photoreceptors and other organic electronics devices. We investigate the mobility of the charge carriers of these materials; measure the ionization potential of these materials, from which we evaluate the positions of the HOMO, LUMO levels, as well as the spectral distribution of the photosensitivity and quantum photogeneration efficiency of these layers. We form the layers by evaporation of these materials as well as by drop casting and spraying their solutions.
Directions of investigations
- Studies of charge transport and carrier drift mobility,
- Theoretical modelling of photoreceptor photodischarge mechanisms and experimental investigation (spectral photo-sensitivity and quantum efficiency of photo-generation),
- Development of electron counters for ionization potential measurements,
- Development of spraying and other technologies for forming and researching active layers of solar cells and other organic electronics devices,
Group members:
Head of group Prof. Dr. Vygintas Jankauskas (more than 170 articles, 28 patents, one monograph).
Habil. Dr. Valentas Gaidelis (more than 50 articles, 40 patents),
Assoc Prof. Dr. Robertas Maldžius (more than 30 articles, 7 patents, one monograph),
Dr. Egidijus Kamarauskas (more than 10 articles),
PhD student Jonas Nekrasovas (more than 3 articles).
Prof. Dr. Vygintas Jankauskas, Habil. Dr. Valentas Gaidelis, PhD student Jonas Nekrasovas (in the first row), PhD student Romas Čapas, Dr. Egidijus Kamarauskas (in the second row) at the ionization potential measuring device.
Equipment
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Thin-layer spray device |
Programmable UV electron spectrometer for investigation of ionization potential of organic semiconductor layers |
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Cylindrical photoreceptor testing equipment, which examines charge transfer and photoreceptor cycling by simulating the operation of a copying or printing device
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A group-developed slow-electron counter used to study the energy levels of organic photoconductors and the electron emission spectrum of a photoconductor
Projects
Project of Research Council of Lithuania „Research of the energy levels and charge transfer parameters of new bipolar organic materials“.
Research and development consulting services agreement with chemical company BASF Schweiz AG „Measurement of physical data of organic molecules“.
Contracts with KTU „Photoelectrical properties of paint and multifunctional organic molecules“.
ELECTRICAL AND DIELECTRICAL PROPERTIES OF SOLID MATERIALS RESEARCH GROUP – group leader dr. Robertas Maldžius
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Maldžius Robertas, Dr. Saulėtekio av. 9, III, 622 85 236 6052 |
Background and Ideas
The demand and usage of the environment friendly and renewable materials is growing. The development of the materials is based on the usage of the modern technologies including Nano and understanding of the physical processes.
- Investigation of the properties of the composite materials on the base of cellulose and development with industry (Stora Enso OY, Finland) new environment friendly materials for the smart packaging and printed electronics
- Investigation of the influence of different coatings, electric field and corona/plasma treatment on the properties of the composite materials based on cellulose
Research group performs
- Experimental investigation of the AC and DC electrical and dielectric properties in the wide range of temperatures and air relative humidity (RH).
- Investigation of the charging and discharging properties of materials in a wide range of temperatures and air RH.
- Investigation of the electro osmotic dewatering and deionisation processes of the cellulose and relative materials.
- Experimental investigation of the absorption of liquids into materials.
Group members has numerous patents among them USP 9447540 and USP 9447541 are issued in 2016. Group consists of the experts in the different fields – physics, physical chemistry, radio engineering. This enables to perform complex investigations. Also group works together with Stora Enso Research Centre (Finland) and Lappeenranta Technical university (Finland) and can use their facilities.
People Talent: Capabilities, skills, activities
- Assoc. prof. dr. Robertas Maldžius (head) – physicist (over 30 publications, 7 patents): expert in the charge transport and electrical/dielectric properties of multi-layered systems. He is able to analyse data using theoretical models or numerical simulation methods.
- Prof. dr. Jonas Sidaravičius – physical chemist (over 100 publications, 23 patents): expert in electrical and dielectric properties of composite materials especially based on cellulose; previous activity – electrophotography (photoreceptors and processes).
- Dr. habil. Valentas Gaidelis – physicist (over 100 publications, 31 patents): expert in the electro osmotic dewatering and deionisation processes.
- Dr. habil. Tadeusz Lozovski – radio engineer (over 80 publications, 10 patents): expert in investigation of charging/discharging processes, he is able to develop sophisticated electronic devices.
- Assoc. prof. dr. Ringaudas Rinkūnas – physicist (over 60 publications): expert in the investigation of the materials structure using electronic microscopy.
Resources
Group has following unique equipment:
- computer controlled climate camera for the testing in a wide range of the environment conditions (left photo),
- dosed corona‘s charging device for the testing of the charging/discharging properties
- laboratory equipment for the electro osmotic dewatering and deionisation of the materials
- Bristow‘s wheel- equipment for the investigation of the absorption of liquids together with the corona/plasma treatment (right photo)
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Ongoing projects, basic publications
Group is performing project ,,Electrical and dielectric properties of cellulose” financed by Stora Enso OY (Finland). Results are published in numerous publications in the prestigious journals. One of the most important are:
- R. Maldžius, J. Sidaravicius, T. Lozovski, K. Backfolk, J. Rosenholm. Temperature-dependence of electrical and dielectric properties of papers for electrophotography // J. Appl Phys., 2010, Vol. 107, issue 11.
- K. Backfolk, J. Sidaravičius, P. Sirviö, R. Maldžius, T. Lozovski, J. B. Rosenholm. Effect of base paper electrolyte content and grammage on electrical and dielectric properties of coated papers // Nordic Pulp&Paper Research J., 2010, Vol. 25, Nr. 3. 319-327.
- J. Sidaravicius, T. Lozovsky, J. Jurksus, R. Maldzius, K. Backfolk, P. Sirviö. Polarization behaviour of paper during corona charging // J. Electrost., 2013, Vol.71, Issue 1, p. 35-40.
- E. Saukkonen, K. Lyytikäinen, K. Backfolk, R. Maldzius, J. Sidaravicius, T. Lozovski, A. Poskus. Effect of the carbohydrate composition of bleached kraft pulp on the dielectric and electrical properties of paper// Cellulose, 2015, Vol.22, Issue 2, p. 1003-1017.
- S.-S. Ovaska, P. Geydt, R. Ringaudas, T. Lozovski, R. Maldzius, J. Sidaravicius, M. Österberg, L. S. Johansson, K. Backfolk. Corona Treatment of filled dual-polymer dispersion coatings: Surface properties and grease resistance // Polymer & Polymer Composites 25.4 (2017): 257.
Key words
Dielectric permittivity, dielectric losses, AC and DC electrical conductivity, charging properties, composite materials, paper, cellulose
Contacts
Vilnius university www.vu.lt
Head: http://web.vu.lt/ff/r.maldzius/kontakt.html
(e-mail: )
TECHNOLOGIES OF NANOSATELLITES RESEARCH GROUP – group leader dr. Liudas Tumonis
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Tumonis Liudas, Dr. Saulėtekio av. 3, A 309 85 223 4558 |
About
Technologies of Nanosatellites Research Group was founded in 2014 to develop space-based technology research at the Faculty of Physics. Primarily, a group led by Dr. Liudas Tumonis participated in the joint developement of VU and UAB Nanoavionika satellite LituanicaSat-2 launched in 2017. Later, the group continued research into various nanosatellites subsystems (especially rocket thrusters).
Group leader Dr. Liudas Tumonis gives lectures on “Fundamentals of Aerospace Technologies” to introduce a faculty's students to space-based technologies.
There is also an opportunity for students to complete their bachelor's and master's theses on satellite subsystem development and research.
Below are the following successfully completed and defended works:
- Investigation of the performance of a nanosatellite rocket engine;
- Numerical modelling of thermodynamic phenomena in a low-thrust rocket engine;
- Design and analysis of magnetic torquer;
- Torsion balance for thruster force measurement;
- Torsion balance for measuring of the μNm level torque;
- Investigation of digital Sun sensor;
- Investigation of MEMS-based inertial navigation system;
- Nanosatellite force measurement stand with magnetic levitation suspension;
- Investigation of a navigation system consisting of few Sun sensors.
Research directions
Small rocket engine research
The group has developed equipment for small rocket engine research. A vacuum chamber is available for testing the engines under vacuum conditions. This equipment was also used for the LituanicaSat-2 satellite and its engine research. The torsion balance type force measuring table allows force measurements within (10-3–10-1) N range at the sample rate of 400 s-1. Currently available test equipment is adapted for the research of environmentally friendly and safe resistojet type thrusters.
Research of magnetorquers
The group has developed measuring equipment to measure the torque generated by magnetic torquers of the order of 10-6 N•m . Optimization and characterization of the properties of these torquers (both core-less and with ferromagnetic cores) are performed.
Navigation sensors research
The group is conducting research on sensors for nano-satellite navigation systems. Characteristics of solar and inertial navigation sensors are investigated and numerical algorithms for sensor data processing are developed.
Projects
Development of LituanicaSat-2 satellite. The team contributed to the development and testing of the satellite rocket engine, as well as to the design and development of various parts of the positioning and control system, radio communication equipment.
Completed project TRACOFUNAT (“Training Courses Fundamentals of Aerospace Technologies”), funded by Lithuanian government via European Space Agency (ESA) under the PECS agreement. During the project, a lecture module for students of the Faculty of Physics “Fundamentals of Aerospace Technologies” was created.
Project TORTILAC (“Development of thermally optimised resistojet for laser ablative cutting fabrication”), funded by Lithuanian government via European Space Agency (ESA) under the PECS agreement. Project will start in 1st quarter of 2020 year. During the project novel design and manufacturing method of water-fueled resistojet will be developed. The project’s consortium consists of Vilnius University (project leader), Center for Physical Science and Technology (FTMC), Vilnius Gediminas Technical University and Nanoavionika.
Personnel
Dr. Liudas Tumonis, senior researcher, group leader. .
Assoc. Prof. Dr. Mindaugas Viliūnas, associate professor, .
