2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect
We present a contactless determination of the two-dimensional electron gas (2DEG) properties in AlScN/GaN and AlYN/GaN high electron mobility transistor (HEMT) structures using the terahertz optical Hall effect (OHE) over a temperature range of 20 K–360 K. The structures are grown on sapphire or 4H-...
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Frontiers Media S.A.
2025-07-01
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| Series: | Frontiers in Electronic Materials |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/femat.2025.1622176/full |
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| author | V. Stanishev V. Stanishev I. Streicher I. Streicher A. Papamichail V. Rindert P. P. Paskov S. Leone V. Darakchieva V. Darakchieva |
| author_facet | V. Stanishev V. Stanishev I. Streicher I. Streicher A. Papamichail V. Rindert P. P. Paskov S. Leone V. Darakchieva V. Darakchieva |
| author_sort | V. Stanishev |
| collection | DOAJ |
| description | We present a contactless determination of the two-dimensional electron gas (2DEG) properties in AlScN/GaN and AlYN/GaN high electron mobility transistor (HEMT) structures using the terahertz optical Hall effect (OHE) over a temperature range of 20 K–360 K. The structures are grown on sapphire or 4H-SiC substrates by metalorganic chemical vapor deposition (MOCVD) and feature ∼10-nm thick barrier layers with Sc and Y contents ranging from 4.6% to 17.3% and 3.3% to 8.2%, respectively. The temperature dependencies of the 2DEG density and mobility parameters are analyzed and discussed in a comparative manner. Additionally, conclusions are drawn regarding the predominant scattering mechanisms at both low and room temperatures. Furthermore, the 2DEG effective mass parameter m* in AlScN/GaN and AlYN/GaN is determined for the first time. At low temperatures m* is found to be in the range 0.20−0.27m0, close to the value of 0.23m0 for bulk GaN. As temperature increases above 100 K, m* gradually rises reaching 0.33−0.39m0 at room temperature, consistent with findings for AlGaN/GaN HEMTs. The underlying causes of this temperature-dependent increase in effective mass are discussed, with a possible explanation linked to polaron effects and deviations from the classical Drude model. |
| format | Article |
| id | doaj-art-e395e4b53d0e48eb82b5a86977a33135 |
| institution | DOAJ |
| issn | 2673-9895 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Electronic Materials |
| spelling | doaj-art-e395e4b53d0e48eb82b5a86977a331352025-08-20T02:40:17ZengFrontiers Media S.A.Frontiers in Electronic Materials2673-98952025-07-01510.3389/femat.2025.162217616221762DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effectV. Stanishev0V. Stanishev1I. Streicher2I. Streicher3A. Papamichail4V. Rindert5P. P. Paskov6S. Leone7V. Darakchieva8V. Darakchieva9NanoLund, Center for III-Nitride Technology, C3NiT - Janzén, Terahertz Materials Analysis Center, THeMAC, and Solid State Physics Division, Lund University, Lund, SwedenTerahertz Materials Analysis Center, THeMAC and Center for III-Nitride technology C3NiT - Janzén, Department of Physics, Chemistry and Biology, (IFM), Linköping University, Linköping, SwedenFraunhofer Institute for Applied Solid State Physics IAF, Freiburg, GermanyConsiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM), Catania, ItalyTerahertz Materials Analysis Center, THeMAC and Center for III-Nitride technology C3NiT - Janzén, Department of Physics, Chemistry and Biology, (IFM), Linköping University, Linköping, SwedenNanoLund, Center for III-Nitride Technology, C3NiT - Janzén, Terahertz Materials Analysis Center, THeMAC, and Solid State Physics Division, Lund University, Lund, SwedenTerahertz Materials Analysis Center, THeMAC and Center for III-Nitride technology C3NiT - Janzén, Department of Physics, Chemistry and Biology, (IFM), Linköping University, Linköping, SwedenFraunhofer Institute for Applied Solid State Physics IAF, Freiburg, GermanyNanoLund, Center for III-Nitride Technology, C3NiT - Janzén, Terahertz Materials Analysis Center, THeMAC, and Solid State Physics Division, Lund University, Lund, SwedenTerahertz Materials Analysis Center, THeMAC and Center for III-Nitride technology C3NiT - Janzén, Department of Physics, Chemistry and Biology, (IFM), Linköping University, Linköping, SwedenWe present a contactless determination of the two-dimensional electron gas (2DEG) properties in AlScN/GaN and AlYN/GaN high electron mobility transistor (HEMT) structures using the terahertz optical Hall effect (OHE) over a temperature range of 20 K–360 K. The structures are grown on sapphire or 4H-SiC substrates by metalorganic chemical vapor deposition (MOCVD) and feature ∼10-nm thick barrier layers with Sc and Y contents ranging from 4.6% to 17.3% and 3.3% to 8.2%, respectively. The temperature dependencies of the 2DEG density and mobility parameters are analyzed and discussed in a comparative manner. Additionally, conclusions are drawn regarding the predominant scattering mechanisms at both low and room temperatures. Furthermore, the 2DEG effective mass parameter m* in AlScN/GaN and AlYN/GaN is determined for the first time. At low temperatures m* is found to be in the range 0.20−0.27m0, close to the value of 0.23m0 for bulk GaN. As temperature increases above 100 K, m* gradually rises reaching 0.33−0.39m0 at room temperature, consistent with findings for AlGaN/GaN HEMTs. The underlying causes of this temperature-dependent increase in effective mass are discussed, with a possible explanation linked to polaron effects and deviations from the classical Drude model.https://www.frontiersin.org/articles/10.3389/femat.2025.1622176/fullHEMT2DEGellipsometryAlScNAlYNeffective mass |
| spellingShingle | V. Stanishev V. Stanishev I. Streicher I. Streicher A. Papamichail V. Rindert P. P. Paskov S. Leone V. Darakchieva V. Darakchieva 2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect Frontiers in Electronic Materials HEMT 2DEG ellipsometry AlScN AlYN effective mass |
| title | 2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect |
| title_full | 2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect |
| title_fullStr | 2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect |
| title_full_unstemmed | 2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect |
| title_short | 2DEG properties of AlScN/GaN and AlYN/GaN HEMTs determined by terahertz optical Hall effect |
| title_sort | 2deg properties of alscn gan and alyn gan hemts determined by terahertz optical hall effect |
| topic | HEMT 2DEG ellipsometry AlScN AlYN effective mass |
| url | https://www.frontiersin.org/articles/10.3389/femat.2025.1622176/full |
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