Advanced Electronic Materials最新文献

Hafnium-oxide-based ferroelectrics have garnered considerable research interest, primarily for their robust ferroelectricity at the nanoscale and their high compatibility with complementary metal-oxide-semiconductors processes. However, the impact of electrodes on the ferroelectric properties of hafnium-oxide layer, particularly that of top electrodes, is not yet fully understood even in the simplest capacitor geometry. In this study, the La_0.67Sr_0.33MnO₃/Hf_0.5Zr_0.5O₂ (LSMO/HZO) epitaxial heterostructure is utilized as a model system to conduct a systematic comparative study on ferroelectricity between the LSMO/HZO (H-LS) bilayer and LSMO/HZO/LSMO (LS-H-LS) trilayer samples. In comparison to the H-LS sample, the LS-H-LS sample exhibits a more uniform polar domain configuration and larger ferroelectric polarization. Moreover, the LS-H-LS sample exhibits significant improvements in leakage, endurance, and retention. These substantial enhancements in ferroelectricity are likely due to interfacial stress imposed by the LSMO capping layer and its capacity to accommodate extra oxygen vacancies. These results underscore the pivotal role of oxide-based top electrodes in determining the ferroelectricity of hafnium-oxide-based heterostructures, providing crucial insights for optimizing the performance of innovative ferroelectric devices.

Industry 4.0 is accelerating the growth of connected devices, resulting in an exponential increase in generated data. The current semiconductor technology is facing challenges in miniaturization and power consumption, demanding for more efficient computation where new materials and devices need to be implemented. One of the most promising candidates for the next technological leap is the memristor. Due to their up-scale manufacturing, the majority of memristors employed conventional deposition techniques (physical and chemical vapor deposition), which can be highly costly. Recently, printed memristors have gained a lot of attention because of their potential for large-scale, fast, and affordable manufacturing. They can also help to reduce material waste, which supports the transition to a more sustainable and environmentally friendly economy. This review provides a perspective on the potential of printed electronics in the fabrication of memristive devices, presenting an overview of the main printing techniques, most suitable for memristors development. Additionally, it focuses on the materials used for the switching layer by comparing its performance. Ultimately, the application of printed memristors is highlighted by showing the tremendous evolution in this field, as well as the main challenges and opportunities that printed memristors are expected to face in the following years.

Benefiting from the outstanding optical, thermal, electrical, and mechanical properties, carbon nanotubes (CNTs) hold significant potential in the fields of materials, physics, chemistry, biology, as well as emerging disciplines such as electronics and optoelectronics. This paper provides a comprehensive review of the latest developments of CNTs optoelectronic devices operating in the terahertz (THz) and infrared (IR) wave range. At the beginning of this review, the unique structural characteristics of CNTs are introduced, overviewing their fundamental electronic structure, and emphasizing their impact on optoelectronics behavior. Further, on various synthesis techniques are discussion employed for the growth of single nanotube and the preparation of CNTs films. The penultimate section, the optical properties of CNTs are analyzed within the THz and IR spectral region and overview the application of THz time-domain spectroscopy in extracting key material parameters of CNTs, and further discuss the theoretical models describing THz conductivity in CNTs. In the end, the most promising CNTs-based device concepts are highlighted for sources, detectors, modulators, absorbers, and sensors within in THz and IR frequency band. This comprehensive review provides a valuable insight into the utilization of CNTs across various aspects of THz and IR optoelectronic devices.

In the rapidly advancing field of bioelectronics, searching for materials that combine superior insulating properties with biocompatibility is crucial, especially for implantable electronic devices. Traditional insulators in mature CMOS processes, though effective, lack biocompatibility, necessitating the exploration of alternative materials. This study introduces tricalcium phosphate (Ca₃(PO₄)₂), a primary component of human bones, and teeth, as an insulating layer material for the first time. High-quality, thickness-controlled Ca₃(PO₄)₂ films are fabricated using magnetron sputtering, and their electrical insulation, stability, and optical transparency have been thoroughly evaluated. To further optimize the insulation performance of Ca₃(PO₄)₂, particularly against residual impurities, and fabrication-induced defects, a bio-friendly low-temperature supercritical fluid desorption (LTSCF-Desorption) technique is developed, effectively removing impurities, repairing defects, and improving the interface states. After LTSCF-Desorption treatment, the leakage current of the Ca₃(PO₄)₂ films is reduced by 30%, along with the enhancements of the films' stability and transmittance. Further material analysis clarified the internal mechanisms behind the improvement of the Ca₃(PO₄)₂ films. Overall, this study not only broadens the application scenarios of Ca₃(PO₄)₂ in bioelectronics but also develops a bio-friendly supercritical desorption technique, providing a new pathway for optimizing the performance of bioelectronic devices and materials.

The potential of skyrmions as information carriers in spintronic devices has garnered significant attention. In this paper, the study investigates the current driven movement behavior of skyrmions in elliptical-ring tracks (ERTs). The findings suggest that the curvature gradient of ERTs can either increase or decrease skyrmion velocity. The increase in velocity aids in transmitting skyrmions, while the decrease in velocity helps in intercepting them. Based on the transmission and interception of skyrmion controlled by the curvature gradient of the ERT, the study has designed diode, logic NOT, AND, and OR gates. The feasibility and robustness of these devices are demonstrated through micromagnetic simulations. The research provides valuable insights and recommendations for designing skyrmion-based devices with curved geometries.

Ultraviolet (UV) photodetectors have gained much attention due to their numerous important applications ranging from environmental monitoring to space communication. To date, most p-NiO/n-Si heterojunction photodetectors (HPDs) exhibit poor UV responsivity and slow response. This is mainly due to a small valence band offset (ΔE_V) at the NiO/Si interface and a high density of dangling bonds at the silicon surface. Herein, an UV HPD consisting of NiO/Al₂O₃/n-Si is fabricated using magnetron sputtering technique. The HPD has a large rectification ratio of 2.4 × 10⁵. It also exhibits excellent UV responsivity (R) of 15.8 A/W at −5 V and and detectivity (D*) of 1.14 × 10¹³ Jones at −4 V, respectively. The excellent performance of the HPD can be attributed to the defect passivation at the interfaces of the heterojunction and the efficient separation of photogenerated carriers by the Al₂O₃ nanolayer. The external quantum efficiency (EQE) of the HPD as high as 5.4 × 10³%, hence implying a large optical gain due to carrier proliferation resulting from impact ionization. Furthermore, the ultrafast response speed with a rise time of 80 µs and a decay time of 184 µs are obtained.

In spiking neural networks (SNNs), artificial sensor neurons are crucial for converting real-world analog information into encoded spikes. However, existing SNNs face challenges due to the inefficient implementation of input sensor neurons. Here, this study proposes an SNN-compatible spike mode sensor, designed to directly convert analog current signals into real-time encoded spikes, feeding the SNN concurrently. The input sensor neuron is realized using a stable neuron circuit employing a threshold switching (TS) memristor and secondary order RC block. This design enables time delay-free spike firing, operates at low voltage, and offers a wide signal sensing range. Furthermore, this study presents an expression delineating the relationship between the pulse emission properties of the circuit and the parameters of its components, laying the basis for circuit components design and development. Analytical analysis confirms the sensor's efficacy in implementing rate-based and time-to-first spike encoding schemes. Integrating the sensor into SNNs as the input layer for image training and recognition tasks yields an impressive accuracy of 87.58% on the MNIST dataset, showcasing its applicability as a crucial interface between the physical world and the SNN framework.

This paper proposes a nanoparticle-based atomic switch network memristive device, capable of both volatile and nonvolatile switching operations, which have not been previously reported for this material. The operational modes can be determined by altering the compliance current, demonstrating high stability over 100 cycles. Analysis of the conduction mechanism using I–V curves reveals switching characteristics consistent with space-charge-limited current conduction during the set process and ohmic behavior in the reset state. Furthermore, this study analyzes these dual-operational modes in devices with varying electrode spacings. The results indicate that a wider spacing necessitated a higher compliance current for the volatile-to-nonvolatile transition, underscoring the significance of interconnection. These findings facilitate the integration of neuron and synapse functions within a single atomic switch network device, thereby advancing neuromorphic systems.