RT Journal Article T1 Synthesis and in-depth interfacial characterization of 2D electron gases formed in Si3N4/Al//KTaO3 heterostructures A1 Martínez, Emanuel Alberto A1 Lucero, Andrea A1 Cantero, Esteban A1 Biskup Zaja, Nevenko A1 Orte, A. A1 Sánchez, Esteban Alejandro A1 Romera Rabasa, Miguel Álvaro A1 Nemes, Norbert Marcel A1 Martínez, José Luis A1 Varela Del Arco, María A1 Grizzi, Oscar A1 Bruno, Flavio Yair AB The two-dimensional electron gas (2DEG) found in KTaO3-based interfaces has garnered attention due to its remarkable electronic properties. In this study, we investigated the conducting system embedded at the Si3N4/Al//KTO(110) heterostructure. We demonstrate that the Al/KTO interface supports a conducting system, with the Si3N4 passivation layer acting as a barrier to oxygen diffusion, enabling ex-situ characterization. Our findings reveal that the mobility and carrier density of the system can be tuned by varying the Al layer thickness. Using scanning transmission electron microscopy, electron energy-loss spectroscopy, X-ray photoemission spectroscopy, and time-of-flight secondary ion mass spectrometry, we characterized the structural and chemical composition of the interface. We found that the Al layer fully oxidizes into AlOx, drawing oxygen from the KTaO3 substrate. The oxygen depletion zone extends 3–5 nm into the substrate and correlates to the Al thickness. Heterostructures with thicker Al layers exhibit higher carrier densities but lower mobilities, likely due to interactions with the oxygen vacancies that act as scattering centers. These findings highlight the importance of considering the effect and extent of the oxygen depletion zone when designing and modeling two-dimensional electron systems in complex oxides. PB Elsevier SN 0169-4332 YR 2025 FD 2025 LK https://hdl.handle.net/20.500.14352/117802 UL https://hdl.handle.net/20.500.14352/117802 LA eng NO E. A. Martínez, A.M. Lucero, E.D. Cantero, N. Biskup, A. Orte, E.A. Sánchez, M. Romera, N.M. Nemes, J.L. Martínez, M. Varela, O. Grizzi and F. Y. Bruno, Appl. Surf. Sci. 689, 162499 (2025) NO This work has been supported by: Comunidad de Madrid (Atraccion ´ de Talento grant No. 2022-5A/IND-24230 and MAD2D-CM-UCM3), grant CNS2022-135485 funded by MCIN/AEI/ 10.13039/ 501100011033 and European Union NextGeneration EU/PRTR, grant from MICINN FEDER PID2021-122980OB-C51, TED2021-129254B-C21 and TED2021-129254B-C22, grants 06/C025-T1 funded by Universidad Nacional de Cuyo, and PIP 11220210100411CO founded by CONICET. E.A.M. acknowledges funding from the European Union (NextGenerationEU), under the Italian Ministry of University and Research (MUR), National Recovery and Resilience Plan (NRRP) grant - TOTEM - CUP E53D23001710006. STEM-EELS measurements carried out at ICTS ELECMI (CNME node, Madrid). NO Comunidad de Madrid NO Ministerio de Ciencia e Innovación (España) NO Agencia Estatal de Investigación (España) NO European Commission NO Universidad Nacional de Cuyo NO Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina) NO Ministero dell'Università e della Ricerca (Italia) DS Docta Complutense RD 30 jul 2025