Research output per year
Research output per year
Research output
- 1 - 50 out of 52 results
Search results
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2025
Infrared bolometers based on 40-nm-Thick Nano-Thermoelectric silicon membranes
Murros, A., Sovanto, K., Tiira, J., Tappura, K., Prunnila, M. & Varpula, A., Mar 2025, In: Infrared Physics and Technology. 145, 105720.Research output: Contribution to journal › Article › Scientific › peer-review
Open Access -
2023
High-performance silicon-based nano-thermoelectric bolometers for uncooled infrared sensing
Varpula, A., Murros, A., Sovanto, K., Rantala, A., Martins, D. G., Tappura, K., Tiira, J. & Prunnila, M., 2023, Electro-Optical and Infrared Systems: Technology and Applications XX. Hickman, D. L., Bursing, H., Kamerman, G. W. & Steinvall, O. (eds.). International Society for Optics and Photonics SPIE, 15 p. 1273702. (Proceedings of SPIE, Vol. 12737).Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
Open AccessFile2 Citations (Scopus)95 Downloads (Pure) -
Uncooled nano-thermoelectric bolometers for infrared imaging and sensing
Varpula, A., Murros, A., Sovanto, K., Rantala, A., Martins, D. G., Tappura, K., Tiira, J. & Prunnila, M., 14 Mar 2023, Optical Components and Materials XX. Jiang, S. & Digonnet, M. J. (eds.). International Society for Optics and Photonics SPIE, 124170U. (Proceedings of SPIE, Vol. 12417).Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
Open AccessFile3 Citations (Scopus)91 Downloads (Pure) -
2022
Characterization of predictable quantum efficient detector at 488 nm and 785 nm wavelengths with an order of magnitude change of incident optical power
Korpusenko, M., Manoocheri, F., Kilpi, O. P., Varpula, A., Kainlauri, M., Vehmas, T., Prunnila, M. & Ikonen, E., Jan 2022, In: Measurement Science and Technology. 33, 1, 015206.Research output: Contribution to journal › Article › Scientific › peer-review
Open Access4 Citations (Scopus) -
2021
Absorber structure for thermal detectors
Tappura, K. (Inventor), Varpula, A. (Inventor) & Prunnila, M. (Inventor), 30 Dec 2021, IPC No. G01J 5/ 20 A I, Patent No. US11402272, Priority date 30 Oct 2019, Priority No. WO2019FI50776Research output: Patent › Patent
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Nano-thermoelectric infrared bolometers
Varpula, A., Tappura, K., Tiira, J., Grigoras, K., Kilpi, O. P., Sovanto, K., Ahopelto, J. & Prunnila, M., Mar 2021, In: APL Photonics. 6, 3, 036111.Research output: Contribution to journal › Article › Scientific › peer-review
Open AccessFile29 Citations (Scopus)295 Downloads (Pure) -
2020
High-performance infrared thermoelectric bolometers based on nanomembranes
Varpula, A., Tappura, K., Tiira, J., Grigoras, K., Viherkanto, K., Ahopelto, J. & Prunnila, M., 26 Feb 2020, Photonic and Phononic Properties of Engineered Nanostructures X. Adibi, A., Lin, S.-Y. & Scherer, A. (eds.). International Society for Optics and Photonics SPIE, 112891O. (Proceedings of SPIE, Vol. 11289).Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
Open AccessFile4 Citations (Scopus)176 Downloads (Pure) -
Thermal detector and thermal detector array
Varpula, A. (Inventor) & Guo, B. (Inventor), 8 Jul 2020, IPC No. G01J 5/ 20 A I, Patent No. EP3676584, Priority date 31 Aug 2018, Priority No. WO2018FI50619Research output: Patent › Patent
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2019
Fast and sensitive thermoelectric bolometers based on silicon nanomembranes
Varpula, A., Tappura, K., Tiira, J., Grigoras, K., Viherkanto, K., Ahopelto, J. & Prunnila, M., 2019.Research output: Contribution to conference › Other conference contribution › Scientific
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2018
Microfabricated sensor platform with through-glass vias for bidirectional 3-omega thermal characterization of solid and liquid samples
Grosse, C., Ras, M. A., Varpula, A., Grigoras, K., May, D., Wunderle, B., Chapuis, P.-O., Gomès, S. & Prunnila, M., 1 Aug 2018, In: Sensors and Actuators A: Physical. 278, p. 33-42Research output: Contribution to journal › Article › Scientific › peer-review
18 Citations (Scopus) -
Mirror plate for a fabry-perot interferometer and a fabry-perot interferometer
Varpula, A. (Inventor), Prunnila, M. (Inventor) & Grigoras, K. (Inventor), 17 Jan 2018, IPC No. G02B 26/ 00 A I, Patent No. EP3268708, Priority date 8 Mar 2016, Priority No. WO2016FI50139Research output: Patent › Patent
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Rapid Thermal Characterization of Materials with Ultra-High Resolution of Droplet Size Specimens using the Three-Omega Method
Grosse, C., Ras, M. A., Grigoras, K., May, D., Varpula, A., Elabshihy, K., Wunderle, B. & Prunnila, M., 24 Jul 2018, Proceedings of the 17th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2018. IEEE Institute of Electrical and Electronic Engineers, p. 562-566 5 p. 8419617Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
1 Citation (Scopus) -
Sensors for Thermal Characterization of Solid and Liquid Samples by 3-Omega Method
Grigoras, K., Varpula, A., Grosse, C., May, D., Ras, M. A. & Prunnila, M., 28 Nov 2018, In: Proceedings. 2, 13, 5 p., 883.Research output: Contribution to journal › Article in a proceedings journal › Scientific › peer-review
Open Access -
Silicon Based Nano-Thermoelectric Bolometers for Infrared Detection
Varpula, A., Grigoras, K., Tappura, K., Timofeev, A., Shchepetov, A., Hassel, J., Ahopelto, J. & Prunnila, M., 6 Dec 2018, In: Proceedings. 2, 5 p.Research output: Contribution to journal › Article in a proceedings journal › Scientific › peer-review
Open Access -
Silicon Membranes for Nanophononics
Varpula, A., Shchepetov, A., Grigoras, K., Hassel, J., Prunnila, M. & Ahopelto, J., 2 Jul 2018, 18th International Conference on Nanotechnology, NANO 2018. IEEE Institute of Electrical and Electronic Engineers, 2 p. 8626348. (Proceedings of the IEEE Conference on Nanotechnology, Vol. 18).Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
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Silicon nano-thermoelectric detectors for for sensing and instrumentation applications
Varpula, A., Renahy, D., Grigoras, K., Tappura, K., Timofeev, A., Shchepetov, A., Hassel, J., Ahopelto, J., Gomès, S. & Prunnila, M., 5 Dec 2018, Book of abstracts. Nanoscale and Microscale Heat Transfer VI : Eurotherm seminar No 111. 192Research output: Chapter in Book/Report/Conference proceeding › Conference abstract in proceedings › Scientific
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Thermal characterization of liquid and solid samples using a measurement platform for the bidirectional 3-omega method
Grosse, C., Ras, M. A., Varpula, A., Grigoras, K., May, D., Wunderle, B. & Prunnila, M., 5 Dec 2018, Book of abstracts. Nanoscale and Microscale Heat Transfer VI: Eurotherm seminar No 111 . 197Research output: Chapter in Book/Report/Conference proceeding › Conference abstract in proceedings › Scientific
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Thermal characterization of thermal interface materials using the three-omega method
Grosse, C., Ras, M. A., Varpula, A., Grigoras, K., May, D., Prunnila, M. & Wunderle, B., 2018, 2018 7th Electronic System-Integration Technology Conference (ESTC). IEEE Institute of Electrical and Electronic Engineers, 8546370Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
2 Citations (Scopus) -
2017
Development, design and fabrication of a measurement chip for thermal material characterization based on the 3-omega method
Grosse, C., Ras, M. A., Varpula, A., Grigoras, K., May, D., Prunnila, M., Wunderle, B. & Gomès, S., 21 Dec 2017, THERMINIC 2017 - 23rd International Workshop on Thermal Investigations of ICs and Systems. IEEE Institute of Electrical and Electronic Engineers, p. 1-5 5 p.Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
2 Citations (Scopus) -
Mirror plate for an optical interferometer and an optical interferometer
Varpula, A. (Inventor), Holmlund, C. (Inventor) & Rissanen, A. (Inventor), 8 Nov 2017, IPC No. G02B 26/ 00 A I, Patent No. EP3241002, Priority date 18 Dec 2015, Priority No. WO2015FI50909Research output: Patent › Patent
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Thermoelectric bolometers based on heavily doped ultra-thin silicon membranes
Varpula, A., Timofeev, A., Shchepetov, A., Grigoras, K., Hassel, J., Ahopelto, J., Ylilammi, M. & Prunnila, M., 2017.Research output: Contribution to conference › Conference article › Scientific
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Thermoelectric bolometers based on silicon membranes
Varpula, A., Timofeev, A. V., Shchepetov, A., Grigoras, K., Ahopelto, J. & Prunnila, M., 1 Jan 2017, Smart Sensors, Actuators, and MEMS VIII. Prunnila, M., Fonseca, L. & Peiner, E. (eds.). International Society for Optics and Photonics SPIE, 102460L. (Proceedings of SPIE, Vol. 10246).Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
6 Citations (Scopus) -
Thermoelectric thermal detectors based on ultra-thin heavily doped single-crystal silicon membranes
Varpula, A., Timofeev, A., Shchepetov, A., Grigoras, K., Hassel, J., Ahopelto, J., Ylilammi, M. & Prunnila, M., 26 Jun 2017, In: Applied Physics Letters. 110, 26, 262101.Research output: Contribution to journal › Article › Scientific › peer-review
33 Citations (Scopus) -
2016
Thermal properties and applications of ultra-thin highly doped silicon membranes
Shchepetov, A., Varpula, A., Timofeev, A., Graczykowski, B., Sotomayor Torres, C., Ahopelto, J. & Prunnila, M., 2016.Research output: Contribution to conference › Conference Abstract › Scientific
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2015
Nondestructive characterization of fusion and plasma activated wafer bonding using mesa and recess structures
Varpula, A., Suni, T. & Dekker, J. R., 2015, In: ECS Journal of Solid State Science and Technology. 4, 2, p. P42 - P52Research output: Contribution to journal › Article › Scientific › peer-review
Open Access5 Citations (Scopus) -
Si, GaAs, and InP as cathode materials for photon-enhanced thermionic emission solar cells
Varpula, A., Tappura, K. & Prunnila, M., 2015, In: Solar Energy Materials and Solar Cells. 134, p. 351-358Research output: Contribution to journal › Article › Scientific › peer-review
48 Citations (Scopus) -
2014
Compact large-aperture Fabry-Pérot interferometer modules for gas spectroscopy at Mid-IR
Kantojärvi, U., Varpula, A., Antila, T., Holmlund, C., Mäkynen, J., Näsilä, A., Mannila, R., Rissanen, A., Antila, J., Disch, R. J. & Waldmann, T. A., 2014, Photonic Instrumentation Engineering. Soskind, Y. G. & Olson, C. (eds.). International Society for Optics and Photonics SPIE, 10 p. 89920C. (Proceedings of SPIE, Vol. 8992).Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
8 Citations (Scopus) -
Contacting mode operation of work function energy harvester
Varpula, A., Laakso, S. J., Havia, T., Kyynäräinen, J. & Prunnila, M., 2014, In: Journal of Physics: Conference Series. 557, 012010.Research output: Contribution to journal › Article › Scientific › peer-review
Open Access9 Citations (Scopus) -
Harvesting vibrational energy using material work functions
Varpula, A., Laakso, S., Havia, T., Kyynäräinen, J. & Prunnila, M., 2014, In: Scientific Reports. 4, 6799.Research output: Contribution to journal › Article › Scientific › peer-review
Open Access35 Citations (Scopus) -
Photon-enhanced thermionic emission solar cells based on Si, GaAs, and InP
Varpula, A. & Prunnila, M., 2014, Proceedings of the 29th European Photovoltaic Solar Energy Conference and Exhibition. WIP Wirtschaft und Infrastruktur GmbH & Co. Planungs KG, p. 331-333Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific
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Silicon based photon-enhanced thermionic emission devices
Varpula, A., Reck, K., Prunnila, M. & Hansen, O., 2014, Workshop Abstracts.Research output: Chapter in Book/Report/Conference proceeding › Conference abstract in proceedings › Scientific
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2013
Emission and absorption entropy generation in semiconductors
Reck, K., Varpula, A., Prunnila, M. & Hansen, O., 2013, Proceedings of the 28th European Photovoltaic Solar Energy Conference and Exhibition. WIP Wirtschaft und Infrastruktur GmbH & Co. Planungs KG, p. 20-23Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific
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2012
Critical scattering in the vicinity of the metal-insulator transition in Mn-doped GaAs
Varpula, A., Novikov, S. & Kuivalainen, P., 2012, In: Physica Status Solidi B: Basic Research. 249, 4, p. 834-839Research output: Contribution to journal › Article › Scientific › peer-review
2 Citations (Scopus) -
Diffusion-emission theory of photon enhanced thermionic emission solar energy harvesters
Varpula, A. & Prunnila, M., 2012, In: Journal of Applied Physics. 112, 4, 044506.Research output: Contribution to journal › Article › Scientific › peer-review
58 Citations (Scopus) -
Glass polarization induced drift in microelectromechanical capacitor
Haarahiltunen, A., Varpula, A., Leinvuo, J., Siren, E., Rytkönen, V.-P. & Savin, H., 2012, In: Journal of Applied Physics. 111, 10, 4 p., 103523.Research output: Contribution to journal › Article › Scientific › peer-review
Open Access2 Citations (Scopus) -
High-k GaAs metal insulator semiconductor capacitors passivated by ex-situ plasma-enhanced atomic layer deposited AlN for Fermi-level unpinning
Jussila, H., Mattila, P., Oksanen, J., Perros, A., Riikonen, J., Bosund, M., Varpula, A., Huhtio, T., Lipsanen, H. & Sopanen, M., 2012, In: Applied Physics Letters. 100, 7, 4 p., 071606.Research output: Contribution to journal › Article › Scientific › peer-review
19 Citations (Scopus) -
Investigation of Si/SiO 2 bonding energy using recess test structure
Varpula, A., Dekker, J. R. & Suni, T., 2012, Proceedings : 3rd IEEE International Workshop on Low Temperature Bonding for 3D Integration, LTB-3D 2012. IEEE Institute of Electrical and Electronic Engineers, 6238089Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
1 Citation (Scopus) -
Single-walled carbon nanotube network field effect transistor as a humidity sensor
Mudimela, P. R., Grigoras, K., Anoshkin, I. V., Varpula, A., Ermolov, V., Anisimov, A. S., Nasibulin, A. G., Novikov, S. & Kauppinen, E. I., 2012, In: Journal of Sensors. 2012, 7 p., 496546.Research output: Contribution to journal › Article › Scientific › peer-review
Open Access13 Citations (Scopus) -
Stability of magnetic polarons in magnetic semiconductor single electron transistors: The effect of Coulomb interaction and external magnetic field
Lebedeva, N., Varpula, A., Novikov, S. & Kuivalainen, P., Nov 2012, In: Physica Status Solidi B: Basic Research. 249, 11, p. 2244-2249Research output: Contribution to journal › Article › Scientific › peer-review
5 Citations (Scopus) -
2011
A compact quantum statistical model for the ballistic nanoscale MOSFETs
Varpula, A., Lebedeva, N. & Kuivalainen, P., Jul 2011, In: Physica Status Solidi A: Applications and Materials Science. 208, 7, p. 1726-1732Research output: Contribution to journal › Article › Scientific › peer-review
3 Citations (Scopus) -
Modeling the effect of mobile ion contamination on the stability of a microelectromechanical resonator
Haarahiltunen, A., Varpula, A. & Savin, H., 15 Aug 2011, In: Journal of Applied Physics. 110, 4, 043505.Research output: Contribution to journal › Article › Scientific › peer-review
3 Citations (Scopus) -
Time dependence of charge transfer processes in diamond studied with positrons
Mäki, J. M., Tuomisto, F., Varpula, A., Fisher, D., Khan, R. U. A. & Martineau, P. M., 16 Nov 2011, In: Physical Review Letters. 107, 21, 217403.Research output: Contribution to journal › Article › Scientific › peer-review
16 Citations (Scopus) -
Transient characterization techniques for resistive metal-oxide gas sensors
Varpula, A., Novikov, S., Haarahiltunen, A. & Kuivalainen, P., 28 Nov 2011, In: Sensors and Actuators B: Chemical. 159, 1, p. 12-26Research output: Contribution to journal › Article › Scientific › peer-review
42 Citations (Scopus) -
2010
Atomic layer deposition of tin dioxide sensing film in microhotplate gas sensors
Niskanen, A. J., Varpula, A., Utriainen, M., Natarajan, G., Cameron, D. C., Novikov, S., Airaksinen, V.-M., Sinkkonen, J. & Franssila, S., 30 Jun 2010, In: Sensors and Actuators B: Chemical. 148, 1, p. 227-232Research output: Contribution to journal › Article › Scientific › peer-review
30 Citations (Scopus) -
Kondo-like resonance at high temperatures in a magnetic semiconductor single-electron transistor
Lebedeva, N., Varpula, A., Novikov, S. & Kuivalainen, P., 1 Dec 2010, In: Physica Scripta T. T141, 014001.Research output: Contribution to journal › Article in a proceedings journal › Scientific › peer-review
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Magnetic polarons in ferromagnetic semiconductor single-electron transistors
Lebedeva, N., Varpula, A., Novikov, S. & Kuivalainen, P., 8 Jun 2010, In: Physical Review B: Condensed Matter and Materials Physics. 81, 23, 235307.Research output: Contribution to journal › Article › Scientific › peer-review
15 Citations (Scopus) -
Modeling of transient electrical characteristics for granular semiconductors
Varpula, A., 1 Aug 2010, In: Journal of Applied Physics. 108, 3, 034511.Research output: Contribution to journal › Article › Scientific › peer-review
11 Citations (Scopus) -
Modelling of dc characteristics for granular semiconductors
Varpula, A., Sinkkonen, J. & Novikov, S., 1 Dec 2010, In: Physica Scripta T. T141, 014003.Research output: Contribution to journal › Article in a proceedings journal › Scientific › peer-review
7 Citations (Scopus) -
Small-signal analysis of granular semiconductors
Varpula, A., Sinkkonen, J. & Novikov, S., 1 Dec 2010, In: Physica Scripta T. T141, 014002.Research output: Contribution to journal › Article in a proceedings journal › Scientific › peer-review
2 Citations (Scopus) -
2008
Bias dependent sensitivity in metal-oxide gas sensors
Varpula, A., Novikov, S., Sinkkonen, J. & Utriainen, M., 14 Apr 2008, In: Sensors and Actuators B: Chemical. 131, 1, p. 134-142 9 p.Research output: Contribution to journal › Article › Scientific › peer-review
38 Citations (Scopus)