New interest in the implementation of ferroelectric tunnel junctions has emerged following the discovery of ferroelectric properties in HfO films, which are fully compatible with silicon microelectronics technology. The coercive electric field to switch polarization direction in ferroelectric HfO is relatively high compared to classical perovskite materials, and thus it can cause the migration of non-ferroelectric charges in HfO, namely charged oxygen vacancies. The charge redistribution would cause the change of the tunnel barrier shape and following change of the electroresistance effect. In the case of ambiguous ferroelectric properties of HfO ultrathin films, this oxygen-driven resistive switching effect can mimic the tunnel electroresistance effect. Here, we demonstrate two separate resistive switching regimes, depending on the applied voltage, in the same memristor device employing a ferroelectric HfZrO (4.5 nm) layer. The first regime originates from the polarization reversal, whereas the second one is attributed to the accumulation/depletion of the oxygen vacancies at the electrode interface. The modulation of the tunnel barrier causes the enhancement of R /R ratio in ∼20 times compared to the tunnel electroresistance effect. The developed device was used to formulate the criteria for unambiguous discrimination between the ferroelectric-and non-ferroelectric resistive switching effects in HfO-based ferroelectric tunnel junctions.
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http://dx.doi.org/10.1088/1361-6528/ab746d | DOI Listing |
Nano Lett
January 2025
Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
The ferroelectric tunnel junction (FTJ) is a competitive candidate for post-Moore nonvolatile memories due to its low power consumption and nonvolatility, with its performance being strongly dependent on the conditions for contact between the ferroelectric material and the metal electrode. The development of two-dimensional materials in recent years has offered new opportunities such as functional metal layers, which is challenging for traditional FTJ systems. Here, we introduce the newly discovered ferroelectric metal WTe as the electrode to construct WTe/α-InSe/Au ferroelectric semiconductor junctions.
View Article and Find Full Text PDFAdv Mater
December 2024
Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
Through the stacking technique of 2D materials, the interfacial polarization can be switched by an interlayer sliding, known as sliding ferroelectricity, which is advantageous in ultra-thin thickness, high switching speed, and high fatigue resistance. However, uncovering the relationship between the sliding path and the polarization state in rhombohedral-stacked materials remains a challenge, which is the key to 2D sliding ferroelectricity. Here, layer-dependent multidirectional sliding ferroelectricity in rhombohedral-stacked InSe (γ-InSe) is reported via dual-frequency resonance tracking piezoresponse force microscopy and conductive atomic force microscopy.
View Article and Find Full Text PDFAdv Mater
December 2024
Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
A synaptic memristor using 2D ferroelectric junctions is a promising candidate for future neuromorphic computing with ultra-low power consumption, parallel computing, and adaptive scalable computing technologies. However, its utilization is restricted due to the limited operational voltage memory window and low on/off current (I) ratio of the memristor devices. Here, it is demonstrated that synaptic operations of 2D InSe ferroelectric junctions in a planar memristor architecture can reach a voltage memory window as high as 16 V (±8 V) and I ratio of 10, significantly higher than the current literature values.
View Article and Find Full Text PDFNano Converg
December 2024
School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-Ro, Yuseong-Gu, Daejeon, 34141, South Korea.
The advancement in high-performance computing technologies, including quantum and aerospace systems, necessitates components that operate efficiently at cryogenic temperatures. In this study, we demonstrate a hafnia-based ferroelectric tunnel junction (FTJ) that achieves a record-high tunneling electroresistance (TER) ratio of over 200,000 and decade-long retention characteristics. By introducing asymmetric oxygen vacancies through the strategic use of indium oxide (InO) layer, we enhance the TER ratio without increasing off-current, addressing the longstanding issue of low on-current in hafnia-based FTJs.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Division of Electronics and Electrical Engineering, Dongguk University, Seoul 04620, Republic of Korea.
In this study, we compare the performance of ferroelectric memristor devices based on the fabrication method for the top electrode, focusing on atomic layer deposition (ALD) and physical vapor deposition techniques. We investigate the effects of these methods on the formation of the orthorhombic phase (o-phase) in HfAlOx (HAO) ferroelectric films, which is crucial for ferroelectric properties. The devices were fabricated with HAO films doped with 3.
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