Gallium nitride (GaN) and related compounds commonly referred to as III-N materials offer significantly more flexible energy gap, higher breakdown electric field intensity, a large spontaneous polarization, high-temperature stability and radiation resistance, but also the high mobility of electrons as compared to the established semiconductors such as Si, GaAs, InP, and related compounds. Therefore, the electronic devices based on III-N semiconductors can withstand significantly higher operation voltages and temperatures (above 300 °C) allowing for realization of devices for higher output powers with smaller physical volume. Devices fabricated from III-N materials may also exhibit the highest achievable switching frequency along with the highest level of the breakdown voltage when compared to typical alternative semiconductor materials. Therefore, there is an effort to develop III-N semiconductor devices, mainly High Electron Mobility Transistors (HEMTs) and Heterostructure Field Effect Transistors (HFETs) with or without insulated gate electrode. Such transistors have the potential to gradually replace Si, Si/SiGe, GaAs, and InP devices in microwave and power applications, discrete solid-state switches and switching amplifiers, logic circuits, and mixed-signal electronics. By “advanced” we mean application of concepts which incorporate novel physical phenomena and unique technologies.
Consequently, we aspire to develop:
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High Electron Mobility Transistors (HEMTs) with InN channel for ultrafast information transfer.
- Advanced GaN-based transistor switches for energy conversion.
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Technology of GaN-based fast mixed-signal circuits.
- GaN-based UV sensors for space applications.
Publications:
Kuzmík, J., Blaho, M., Gregušová, D., Eliáš, P., Pohorelec, O., Hasenöhrl, S., Haščík, Š., Gucmann, F., Zápražný, Z., Dobročka, E., Kyambaki, M., and Konstantinidis, G.: Growth and performance of n++ GaN cap layer for HEMTs applications, Mater. Sci Semicond. Process. 185 (2025) 108959.
Kuzmík, J., Stoklas, R., Hasenöhrl, S., Dobročka, E., Kučera, M., Eliáš, P., Gucmann, F., Gregušová, D., Haščík, Š., Kaleta, A., Chauvat, M.P., Kret, S., and Ruterana, P.: InN/InAlN heterostructures for new generation of fast electronics, J. Applied Phys. 135 (2024) 245701.
Kuzmík, J., Pohorelec, O., Hasenöhrl, S., Blaho, M., Stoklas, R., Dobročka, E., Rosová, A., Kučera, M., Gucmann, F., Gregušová, D., Precner, M., and Vincze, A.: Mg doping of N-polar, in-rich InAlN, Materials, 16 (2023) 2250.
Šichman, P., Stoklas, R., Hasenöhrl, S., Gregušová, D., Ťapajna, M., Hudec, B., Haščík, Š., Hashizume, T., Chvála, A., Šatka, A., and Kuzmík, J.: Vertical GaN transistor with semi-insulating channel, Physica Status Solidi (a) 220 (2023) SI2200776.
Hasenöhrl, S., Blaho, M., Dobročka, E., Gucmann, F., Kučera, M., Nádaždy, P., Stoklas, R., Rosová, A., and Kuzmík, J.: Growth of N-polar In-rich InAlN by metal organic chemical vapor deposition on on- and off-axis sapphire, Mater. Sci Semicond. Process. 156 (2023) 107290.
Stoklas, R., Hasenőhrl, S., Dobročka, E., Gucmann, , and Kuzmík, J.: Electron transport properties in thin InN layers grown on InAlN, Mater. Sci Semicond. Process. 155 (2023) 107250.
Rosová, A., Dobročka, E., Eliáš, P., Hasenöhrl, S., Kučera, M., Gucmann, F., and Kuzmík, J.: In(Ga)N 3D growth on GaN-buffered on-axis and off-axis (0001) sapphire substrates by MOCVD, Nanomater. 12 (2022) 3496.
Kuzmík, J., Adikimenakis, A., Ťapajna, M., Gregušová, D., Haščík, Š., Dobročka, E., Tsagaraki, K., Stoklas, R., and Georgakilas, A.: InN: breaking the limits of solid-state electronics, AIP Adv. 11 (2021) 125325.
Gucmann, F., Kučera, M., Hasenőhrl, S., Eliáš, P., Rosová, A., Dobročka, E., Stoklas, R., and Kuzmík, J.: InN crystal habit, structural, electrical, and optical properties affected by sapphire substrate nitridation in N-polar InN/InAlN heterostructures, Semicond. Sci Technol. 36 (2021) 075025.
Stoklas, R., Chvála,, Šichman, P., Hasenöhrl, S., Haščík, Š., Priesol, J., Šatka, A., and Kuzmík, J.: Analysis and modeling of vertical current conduction and breakdown mechanisms in semi-insulating GaN grown on GaN: role of deep levels, IEEE Trans. Electron Dev. 68 (2021) 2365.
Hasenöhrl, S., Dobročka, E., Stoklas, R., Gucmann, F., Rosová, A., and Kuzmík, J.: Growth and Properties of N-polar InN/InAlN Heterostructures, Phys. Stat. sol (a) 217 (2020) 2000197.
Pohorelec, O., Ťapajna, M., Gregušová, D., Gucmann, F., Hasenöhrl, S., Haščík, Š., Stoklas, R., Seifertová, A., Pécz, B., Tóth, L., and Kuzmík, J.: Investigation of interfaces and threshold voltage instabilities in normally-off MOS-gated InGaN/AlGaN/GaN HEMTs, Applied Surface Sci 528 (2020) 146824.
Šichman, P., Hasenöhrl, S., Stoklas, R., Priesol, J., Dobročka, E., Haščík, Š., Gucmann, F., Vincze, A., Chvála, A., Marek, J., Šatka, A., and Kuzmík, J.: Semi-insulating GaN for vertical structures: role of substrate selection and growth pressure, Mater. Sci Semicond. Process. 118 (2020) 105203.
Adikimenakis, A., Chatzopoulou, P., Dimitrakopulos, G. P., Kehagias, Th., Tsagaraki, K., Androulidaki, M., Doundoulakis, G., Kuzmík, J., and Georgakilas, A.: Correlation of threading dislocations with the electron concentration and mobility in InN heteroepitaxial layers grown by MBE, ECS J. Solid State Sci Technol. 9 (2020) 015006.
Chauhan, P., Hasenöhrl, S., Vančo, Ľ., Šiffalovič, P., Dobročka, E., Machajdík, D., Rosová, A., Gucmann, F., Kováč, J.jr., Maťko, I., Kuball, M., and Kuzmík, J.: A systematic study of MOCVD reactor conditions and Ga memory effect on properties of thick InAl(Ga)N layers: A complete depth-resolved investigation, CrystEngComm 22 (2020) 130-141.
Chauhan, P., Hasenöhrl, S., Minj, A., Chauvat, M.P., Ruterana, P., and Kuzmík, J.: Growth evolution of N-polar Indium-rich InAlN layer on c-sapphire via strain relaxation by ultrathin AlON interlayer, Applied Surface Sci 502 (2020) 144086.
Chvála, A., Nagy, L., Marek, J., Priesol, J., Donoval, D., Šatka, A., Blaho, M., Gregušová, D., and Kuzmík, J.: Device and circuit models of monolithic InAlN/GaN NAND and NOR logic cells comprising D- and E-mode HEMTs, J. Circuits, Systems Computers 28 (2019) 1940009.
Adikimenakis, A., Androulidaki, M., Foundoulaki Salhin, E., Tsagaraki, K., Doundoulakis, G., Kuzmík, J., and Georgakilas, A.: Bandgap, electrical and structural properties of thick InN (0001) films grown under optimal conditions, IOP Conf. Ser.: J. Phys. 1190 (2019) 012010.
Gregušová, D., Tóth, L., Pohorelec, O., Hasenöhrl, S., Haščík, Š., Cora, I., Fogarassy, Z., Stoklas, R., Seifertová, A., Blaho, M., Laurenčíková, A., Oyobiki, T., Pécz, B., Hashizume, T., and Kuzmík, J.: InGaN/(GaN)/AlGaN/GaN normally-off metal-oxide-semiconductor high-electron mobility transistors with etched access region, Japan. J. Applied Phys. 58 (2019) SCCCD21.
Chauhan, P., Hasenöhrl, S., Dobročka, E., Chauvat, M.-P., Minj, A., Gucmann, F., Vančo, Ľ., Kováč, J.jr., Kret, S., Ruterana, P., Kuball, M., Šiffalovič, P., and Kuzmík, J.: Evidence of relationship between strain and In-incorporation: growth of N-polar In-rich InAlN buffer layer by OMCVD, J. Applied Phys. 125 (2019) 105304.
Ťapajna, M., Drobný, J., Gucmann, F., Hušeková, K., Gregušová, D., Hashizume, T., and Kuzmík, J.: Impact of oxide/barrier charge on threshold voltage instabilities in AlGaN/GaN metal-oxide-semiconductor heterostructures, Mater. Sci in Semicond Process. 91 (2019) 356-361.
Chauhan, P., Hasenöhrl, S., Dobročka, E., Vančo Ľ., Stoklas, R., Kováč, J., Šiffalovič, P., and Kuzmík, J.: Effect of temperature and carrier gas on the properties of thick InxAl1-xN layer, Applied Surface Sci 470 (2019) 1-7.
Hasenöhrl, S., Chauhan, P., Dobročka, E., Stoklas, R., Vančo, Ľ., Veselý, M., Bouazzaoui, F., Chauvat, M.-P., Reterana, P., and Kuzmík, J.: Generation of hole gas in non-inverted InAl(Ga)N/GaN heterostructures, Applied Phys. Express 12 (2019) 014001.
Kučera, M., Adikimenakis, A., Dobročka, E., Kúdela, R., Ťapajna, M., Laurenčíková, A., Georgakilas, A., and Kuzmík, J.: Structural, electrical, and optical properties of annealed InN films grown on sapphire and silicon substrates, Thin Solid Films 672 (2019) 114-119.
Gucmann, F., Ťapajna, M., Pohorelec, O., Haščík, Š., Hušeková, K., and Kuzmík, J.: Creation of two-dinesional electron gas and role of surface donors in III-N metal-oxide-semiconductor high-electron mobility transistors, Phys. Status Solidi A 215 (2018) 1800090.
Stoklas, R., Gregušová, D., Hasenöhrl, S., Brytavskyi, I.V., Ťapajna, M., Fröhlich, , Haščík, Š., Gregor, M., and Kuzmík, J.: Characterization of interface states in AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with HfO2 gate dielectric grown by atomic layer deposition, Applied Surface Sci 461 (2018) 255-259.
Dobročka, E., Hasenöhrl, S., Chauhan, P., and Kuzmík, J.: Non-conventional scans in high-resolution X-ray diffraction analysis of epitaxial systems, Applied Surface Sci 461 (2018) 23-32.
Hashizume, T., Nishiguchi, K., Kaneki, S., Kuzmik, J., and Yatabe, Z.: State of the art on gate insulation and surface passivation for GaN-based power HEMTs, Mater. Sci in Semicond. Process. 78 (2018) 85-95.
Chvála, A., Nagy, L., Marek, J., Priesol, J., Donoval, D., Blaho, M., Gregušová, D., Kuzmík, J., and Šatka, A.: Characterization of monolithic InAlN/GaN NAND logic cell supported by circuit and device simulations, IEEE Trans. Electron Devices 65 (2018) 2666-2669.
Blaho, M., Gregušová, D., Haščík, Š., Ťapajna, M., Fröhlich, K., Šatka, A., Kuzmík, J., : Annealing, temperature, and bias-induced threshold voltage instabilities in integrated E/D-mode InAlN/GaN MOS HEMTs. Applied Phys. Lett. 111 (2017) 033506. (APVV 15-0673). (CENTE).
Graff, A., Simon-Najasek, M., Altmann, F., Kuzmík, J., Gregušová, D., Haščík, Š., Jung, J., Baur, T., Grunenputt, J., and Blanck, H.: High resolution physical analysis of ohmic contact formation at GaN-HEMT devices, Microelectron. Reliab. 76-77 (2017) 338.
Kuzmík, J., Fleury, C., Adikimenakis, A., Gregušová, D., Ťapajna, M., Dobročka, E., Haščík, Š., Kučera, M., Kúdela, R., Androulidaki, M., Pogany, D., Georgakilas, A., : Current conduction mechanism and electrical break-down in InN grown on GaN. Applied Phys. Lett. 110 (2017) 232103. (APVV 15-0031). (CENTE II).
Ťapajna, M., Stoklas, R., Gregušová, D., Gucmann, F., Hušeková, K., Haščík, Š., Fröhlich, K., Tóth, L., Pecz, B., Brunner, F., Kuzmík, J., : Investigation of ‘surface donors’ in Al2O3/AlGaN/GaN metal-oxide-semiconductor heterostructures: Correlation of electrical, structural, and chemical properties. Applied Surface Sci 426 (2017) 656-661. (CENTE II). (APVV 15-0031). (VEGA 2/0138/14).
Ťapajna, M., Válik, L., Gucmann, F., Gregušová, D., Fröhlich, K., Haščík, Š., Dobročka, E., Tóth, L., Pecz, B.,Kuzmík, J., : Low-temperature atomic layer deposition-grown Al2O3 gate dielectric for GaN/AlGaN/GaN MOS HEMTs: Impact of deposition conditions on interface state density. J. Vacuum Sci Technol. B 35 (2017) 01A107. (SAFEMOST). (VEGA 2/0138/14). (CENTE).
Gregušová, D., Blaho, M., Haščík, Š., Šichman, P., Laurenčíková, A., Seifertová, A., Dérer, J., Brunner, F., Würfl, H., Kuzmík, J., : Polarization-engineered n+GaN/InGaN/AlGaN/GaN normally-off MOS HEMTs. Physica Status Solidi a 214 (2017) 1700407. (HiPoSwitch). (APVV 15-0031). (SAFEMOST). (VEGA 2/0109/17).
Ťapajna, M., Hilt, O., Bahat-Triedel, E., Würfl, H., Kuzmík, J., : Gate reliability investigation in normally-off p-type-gan cap/AlGaN/GaN HEMTs under forward bias stress. IEEE Electron Device Lett. 37 (2016) 385 – 388.
Matys, M., Stoklas, R., Kuzmík, J., Adamowicz, J., Yatabe, Z., Hashizume, T., : Characterization of capture cross sections of interface states in dielectric/III-nitride heterojunction structures. J. Applied Phys. 119 (2016) 205304.
Blaho, M., Gregušová, D., Haščík, Š., Seifertová, A., Ťapajna, M., Šoltýs, J., Šatka, A., Nagy, L., Chvála, A., Marek, J., Carlin, J., Grandjean, N., Konstantinidis, G., Kuzmík, J., : Technology of integrated self-aligned E/D-mode n++GaN/InAlN/AlN/GaN MOS HEMTs for mixed-signal electronics. Semicond. Sci Technol. 31 (2016) 065011. (CENTE). (APVV 0367-11). (VEGA 2/0138/14).
Kuzmík, J., Haščík, Š., Kučera, M., Kúdela, R., Dobročka, E., Adikimenakis, A., Mičušík, M., Gregor, M., Plecenik, A., Georgakilas, A., : Elimination of surface band bending on N-polar InN with thin GaN capping,. Applied Phys. Lett. 107 (2015) 191605. (APVV 0367-11). (VEGA 2/0138/14). (CENTE).
Ťapajna, M., Hilt, O., Bahat-Triedel, E., Würfl, H., Kuzmík, J., : Investigation of gate-diode degradation in normally-off p-GaN/AlGaN/GaN high-electron-mobility transistors. Applied Phys. Lett. 107 (2015) 193506.(HiPoSwitch). (VEGA 2/0138/14). (CENTE).
Blaho, M., Gregušová, D., Haščík, Š., Jurkovič, M., Ťapajna, M., Fröhlich, K., Dérer, J., Carlin, J., Grandjean, N., Kuzmík, J., : Self-aligned normally-off metal-oxide-semiconductor n+++GaN/InAlN/GaN high-electron mobility transistors. Phys. Status Solidi A 112 (2015) 1086-1090. (MORGaN). (APVV 0367-11). (VEGA 2/0138/14). (CENTE).
Gregušová, D., Jurkovič, M., Haščík, Š., Blaho, M., Seifertová, A., Fedor, J., Ťapajna, M., Fröhlich, K., Vogrinčič, P., Liday, J., Derluyn, J., Germain, M., Kuzmík, J., : Adjustment of threshold voltage in AlN/AlGaN/GaN high-electron mobility transistors by plasma oxidation and Al2O3 atomic layer deposition overgrowth. Applied Phys. Lett. 104 (2014) 013506. (HiPoSwitch). (APVV 0367-11). (VEGA 2/0105/13).
Kuzmík, J., Jurkovič, M., Gregušová, D., Ťapajna, M., Brunner, F., Cho, E., Meneghesso, G., Würfl, H., :Degradation of AlGaN/GaN high-electron mobility transistors in the current-controlled off-state breakdown. J. Applied Phys. 115 (2014) 164504. (HiPoSwitch). (CENTE II). (APVV 0104-10).
Ťapajna, M., Jurkovič, M., Válik, L., Haščík, Š., Gregušová, D., Brunner, F., Cho, E., Hashizume, T., Kuzmík, J., : Impact of GaN cap on charges in Al2O3/(GaN/)AlGaN/GaN metal-oxide-semiconductor heterostructures analyzed by means of capacitance measurements and simulations. J. Applied Phys. 116 (2014) 104501.(HiPoSwitch). (CENTE). (APVV 0367-11). (VEGA 2/0138/14).