Recently, 2-dimensional electron gas (2-DEG) was discovered at the interface of Al₂O₃/SrTiO₃ (STO) heterostructures, in which the amorphous Al₂O₃ layers were grown by atomic layer deposition (ALD). The saturated electron density at the Al₂O₃/STO heterostructures above the critical thickness of Al₂O₃ is explained by an oxygen diffusion mechanism.
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http://dx.doi.org/10.1039/c3nr03082b | DOI Listing |
Adv Mater
January 2025
Department of Physics, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang, 37673, Korea (the Republic of).
Janus materials, a novel class of materials with two faces of different chemical compositions and electronic polarities, offer significant potential for various applications with catalytic reactions, chemical sensing, and optical or electronic responses. A key aspect for such functionalities is face-dependent electronic bipolarity, which is usually limited by the chemical distinction of terminated surfaces and has not been exploited in the semiconducting regime. Here, it is showed that a Janus and Kagome van der Waals (vdW) material NbTeI has ferroelectric-like coherent stacking of the Janus layers and hosts strong electronic bipolar states in the semiconducting regime.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Two-dimensional (2D) PdSe atomic crystals hold great potential for optoelectronic applications due to their bipolar electrical characteristics, tunable bandgap, high electron mobility, and exceptional air stability. Nevertheless, the scalable synthesis of large-area, high-quality 2D PdSe crystals using chemical vapor deposition (CVD) remains a significant challenge. Here, we present a self-limiting liquid-phase edge-epitaxy (SLE) low-temperature growth method to achieve high-quality, centimeter-sized PdSe films with single-crystal domain areas exceeding 30 μm.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Materials Science, Kaunas University of Technology, K. Baršausko 59, LT-51423 Kaunas, Lithuania.
This study explores the low-temperature synthesis of graphene using plasma-enhanced chemical vapor deposition (PECVD), emphasizing the optimization of process parameters to achieve controlled growth of pristine and hydrogenated graphene. Graphene films were synthesized at temperatures ranging from 700 °C to as low as 400 °C by varying methane (25-100 sccm) and hydrogen (25-100 sccm) gas flow rates under 10-20 mBar pressures. Raman spectroscopy revealed structural transitions: pristine graphene grown at 700 °C exhibited strong 2D peaks with an I(2D)/I(G) ratio > 2, while hydrogenated graphene synthesized at 500 °C showed increased defect density with an I(D)/I(G) ratio of ~1.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Clausius Institut für Physikalische und Theoretische Chemie, Universität Bonn, Bonn 53115, Germany.
The carpet growth of alkali halide (AH) layers across step edges of substrates enables the growth of seamless and continuous large domains. Yet, information about how the AH layer adapts continuously to the height difference between the terraces on the two sides of a step is only described by continuum models, which do not give details of the ionic displacements. Here, we present a first study of thin epitaxial KCl(100) layers grown on the Ag(111) surface by scanning tunneling microscopy that provides atomistic details for the first time.
View Article and Find Full Text PDFACS Nano
January 2025
BK21 Graduate Program in Intelligent Semiconductor Technology, Seoul 03722, Republic of Korea.
MoS, one of the most researched two-dimensional semiconductor materials, has great potential as the channel material in dynamic random-access memory (DRAM) due to the low leakage current inherited from the atomically thin thickness, high band gap, and heavy effective mass. In this work, we fabricate one-transistor-one-capacitor (1T1C) DRAM using chemical vapor deposition (CVD)-grown monolayer (ML) MoS in large area and confirm the ultralow leakage current of approximately 10 A/μm, significantly lower than the previous report (10 A/μm) in two-transistor-zero-capacitor (2T0C) DRAM based on a few-layer MoS flake. Through rigorous analysis of leakage current considering thermionic emission, tunneling at the source/drain, Shockley-Read-Hall recombination, and trap-assisted tunneling (TAT) current, the TAT current is identified as the primary source of leakage current.
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