ACS Applied Electronic Materials最新文献

This paper presents a near-infrared (NIR) organic light-dependent resistor (OLDR) utilizing 5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine (ONc) as the photoactive material, and investigates the influence of preparation parameters on device performance. A flexible interdigitated electrode configuration is employed to fully leverage the excellent mechanical flexibility of organic semiconductor materials. ONc exhibits strong NIR absorption near 924 nm, enabling effective photoresponse under low-light conditions. The device displays typical LDR characteristics and operates stably at a low bias of 2 V, meeting the requirements of optical sensors for low-power, high-response operation. Fabrication is conducted via solution processing, with performance tuning achieved by varying ONc concentration (1–15 mg/mL) and annealing temperature (room temperature to 100 °C). Optimal performance is obtained at a concentration of 10 mg/mL and an annealing temperature of 50 °C, yielding a photocurrent of 52.084 nA under a light intensity of 40.5 mW/cm². The response and recovery times are 2.173 and 2.185 s, respectively, accompanied by a significant change in resistance of 68.63%. Furthermore, the study explores carrier transport mechanisms and interfacial behavior through morphological analysis and energy-level simulations, providing both theoretical insights and practical guidelines for the development of high-performance, flexible NIR OLDRs.

We achieved ultrahigh photocurrent in a deep-ultraviolet (DUV) photodetector with a Li-doped NiO (p+)/NiO (p)/β-Ga₂O₃ (n) heterojunction by designing a top electrode pattern and adding Li-doped NiO as a p+ layer. In DUV photodetectors, the pattern of the top electrode significantly influences device performance, including the electric field distribution, charge collection efficiency, and active area. Additionally, the incorporation of a p+ layer between the metal and p-type semiconductor can modify the band diagram, improve the quality of the ohmic contact, and enhance charge-transport characteristics. The device used an optimized electrode pattern with a Li-doped NiO layer as a p+ layer and demonstrated remarkable results at a wavelength of 254 nm and a light intensity of 1000 μW/cm². It achieved a photocurrent of 2.0 μA at zero bias and 3.9 μA at 5 V. Furthermore, to evaluate the effectiveness of the device for arc detection, additional measurements were conducted at a wavelength of 222 nm, which lies within the peak wavelength range of arc emissions. The device recorded photocurrents of 2.4 μA at zero bias and 5.1 μA at 5 V, thus effectively demonstrating the capability to detect arcs. These results highlight the potential of adjusting previously unexplored parameters in NiO/β-Ga₂O₃ heterojunction-based DUV photodetectors to achieve significantly enhanced photocurrent levels.

This study presents a temperature-responsive memristive device based on a graphene oxide–poly(vinyl alcohol) (GO–PVA) composite, fabricated using a simple drop-casting and sputtering approach. Incorporating PVA into GO preserves the multilayer structure (6–8 layers) while enhancing film uniformity and mechanical integrity. The Cr/GO–PVA/Cr memristor demonstrates stable analog resistive switching with endurance exceeding 1000 cycles, significantly outperforming pristine GO devices. A comprehensive temperature-dependent analysis reveals a transition in charge transport mechanisms from variable-range hopping (VRH) and space-charge-limited current (SCLC) at low temperatures to Ohmic and Schottky conduction at elevated temperatures due to thermal activation and partial GO reduction. Moreover, synaptic emulation capabilities improve at higher temperatures, particularly in the linearity and precision of potentiation/depression (LTP/LTD) characteristics. These findings highlight GO–PVA composites as promising candidates for thermally stable, energy-efficient, and neuromorphic-memristive systems.

2D/3D heterojunction tunnel transistors are promising for low-power logic applications owing to their steep subthreshold swing. Moreover, a broken-gap heterojunction is essential to enhance the current in a tunnel device. However, there is rare experimental work of 2D/3D broken-gap heterojunctions with clear negative differential resistance (NDR) and gate-tunable tunneling characteristics. In this work, we demonstrate a top-gated SnS₂/p⁺–Ge heterojunction tunnel diode with a broken-gap alignment, exhibiting unambiguous negative differential resistance and an exceptionally high peak-to-valley ratio (PVCR) of approximately 4.7, the highest reported among all 2D/3D heterojunction tunnel diodes. Our results clearly demonstrate gate tunability of band-to-band tunneling in a SnS₂/p⁺–Ge heterojunction diode for advanced electronic applications.

Tungsten is a common electrode material for Hf_0.5Zr_0.5O₂ (hafnium zirconium oxide) ferroelectric devices, and WO₃ can form at the interfaces. Here, the role of WO₃ interfacial layers in controlling the oxygen vacancy behavior in Hf_0.5Zr_0.5O₂–WO₃ (HZO/WO₃) heterostructures is investigated using density functional theory (DFT). Charge transition level (CTL) analysis shows that the (+2/0) level lies above the conduction band minimum of WO₃, suggesting that oxygen vacancies are thermodynamically stable in the doubly charged state (V_O²⁺) throughout the entire accessible Fermi-level range of the heterostructure. Corresponding formation energy calculations reveal that, at the Fermi level determined by the charge neutrality level calculations, these charged vacancies exhibit the lowest formation energies in the WO₃ region (−0.44 eV) and progressively higher energies toward HZO (up to ∼1.26 eV), demonstrating a strong thermodynamic driving force for vacancy localization in WO₃. Migration barrier calculations further reveal that V_O²⁺ defects can diffuse readily from HZO to WO₃, with interfacial barriers as low as 0.45–0.68 eV. These results demonstrate that WO₃ serves as both a thermodynamic sink and a kinetic trap for charged oxygen vacancies, offering a promising pathway to suppress defect-induced degradation and improve endurance in HZO-based ferroelectric devices: instead of striving for an abrupt HZO/W interface, an engineered interlayer of WO₃ would be advantageous.

The rapid advancement of flexible electronics has imposed stricter performance requirements on conductive pastes, particularly in terms of electrical conductivity, mechanical flexibility, and process compatibility. This study addresses the lack of a systematic framework for selecting organic vehicles tailored to the specific needs of flexible substrates in electronic device fabrication and proposes an optimization strategy. By integrating gradient solvent design, a polyurethane–acrylic resin composite binder system, and functional additive modulation, we achieved targeted control over multiple performance metrics of the conductive paste. Experiments demonstrated that a gradient solvent system composed of butyl acetate (BAC) and diethylene glycol butylether acetate (DBAC) (18:53.5) effectively suppressed the coffee-ring effect and improved the curing behavior. The composite binder of polyurethane and acrylic resin (10:5) provided a balance between flexibility and interfacial adhesion, resulting in a resistance change of less than 7.71% after 30 cycles of 180° bending. The incorporation of 4 wt % polyamide wax and 2 wt % anionic dispersant TDO further reduced the resistivity to (4.30 ± 1.41) × 10^–4 Ω·cm and improved printing resolution. The optimized conductive paste was successfully screen printed on polyimide substrates, forming continuous circuits with a minimum line width of 0.2 mm. The printed patterns exhibited excellent conductivity [ρ < (3.06 ± 0.08) × 10^–4 Ω·cm], bending stability (ΔR/R₀ < 1.82), and strong adhesion (5B level) and were successfully implemented in flexible circuit prototypes. This systematic optimization strategy overcomes the limitations of traditional one-variable approaches, offering a pathway for the rational design of high-performance conductive pastes and contributing to the industrial advancement of flexible electronic devices.

An artificial neural network (ANN) model based on Bayesian regularization (BR) was developed to predict the electrical conductivity σ (T, x) of Pr_0.8K_0.2–xNa_xMnO₃ ceramics (with x = 0.00, 0.05, 0.10, 0.15, and 0.20) based on experimental data. The model was trained to evaluate the conductivity behavior in detail, demonstrating highly accurate and fast predictions. The ANN approach significantly accelerates material characterization by reducing the experimental workload and time. The best prediction accuracy achieved was 99.95%, with a root mean square error (RMSE) of 7.9817 × 10^–7, a mean absolute error (MAE) of 0.0379 S/m, and a mean absolute percentage error (MAPE) of 1.30% at 1000 training epochs. The trained model was then used to forecast the electrical behavior at finer sodium concentration intervals (1%) and with higher temperature resolution (2 K steps up to 500 K, compared with the original 20 K steps). Finally, ANN predictions were used to identify suitable materials for thermal sensors and related applications.

The plasmonic hot-electron effect is key to advancing multifunctional photodetection, enhancing light–matter interactions, boosting absorption and detection sensitivity, and extending wavelength ranges and spectral responses. In two-dimensional vertical heterojunctions with short carrier migration distances, their role in optimizing photodetection and regulating visual synapses is a critical frontier. This paper proposes an Ag/MoTe₂/graphene (Gr) vertical heterojunction with codirectional built-in electric fields at Ag/MoTe₂ and MoTe₂/Gr interfaces for efficient carrier transport, where the Ag electrode introduces the plasmonic hot-electron effect as the key to enhanced performance, extending the self-powered infrared detection range to 1550 nm and achieving a responsivity of up to 0.3 A/W under 660 nm light illumination. Notably, the heterojunction exhibits excellent visual synaptic performance, including tunable plasticity dependent on parameters, PPF modulation, and ultralow energy consumption of 1.5 pJ per spike. Within the temperature range 300–340 K, enhanced phonon scattering partially suppresses the plasmonic hot-electron effect, thereby reducing the impact of temperature rise on the synaptic current. The Ag/MoTe₂/Gr vertical heterojunction shows good temperature stability over the Gr/MoTe₂/Gr vertical heterojunction, confirming its potential for building thermally stable neuromorphic vision systems and self-powered optoelectronics.