Solid-state Devices Research Articles

Quantum paraelectric varactors for radiofrequency measurements at millikelvin temperatures

Radiofrequency reflectometry can provide fast and sensitive electrical read-out of charge and spin qubits in quantum dot devices coupled to resonant circuits. In situ frequency tuning and impedance matching of the resonator circuit using voltage-tunable capacitors (varactors) is needed to optimize read-out sensitivity, but the performance of conventional semiconductor- and ferroelectric-based varactors degrades substantially in the millikelvin temperature range relevant for solid-state quantum devices. Here we show that strontium titanate and potassium tantalate, materials which can exhibit quantum paraelectric behaviour with large field-tunable permittivity at low temperatures, can be used to make varactors with perfect impedance matching and resonator frequency tuning at 6 mK. We characterize the varactors at 6 mK in terms of their capacitance tunability, dissipative losses and magnetic field insensitivity. We use the quantum paraelectric varactors to optimize the radiofrequency read-out of carbon nanotube quantum dot devices, achieving a charge sensitivity of 4.8 μe Hz−1/2 and a capacitance sensitivity of 0.04 aF Hz−1/2.

Solid-state friction rolling repair technology for various forms of defects through multi-layer multi-pass deposition

The current Friction Stir Welding (FSW) based solid-state defect repairing method is an ideal repair technology for high-strength aluminum alloy. However, due to the limitation of pin length and the existence of shoulder, the stirring pin cannot penetrate deep into the root of defects and is difficult to extend in the width direction, which poses great challenges for components with large defects, such as one-dimensional, two-dimensional and volume defects. To overcome these limitations, this study successfully achieved effective repair of various forms of defects using the solid-state Friction Rolling Repair (FRR) technology through multi-layer multi-bead deposition. The microstructure and mechanical properties of the repaired ZL114A cast aluminum alloy joints were investigated. The results demonstrate well-bonded repaired boundaries, significant grain refinement at the junction between the repaired area and boundary, and ultimate tensile strength exceeding 80 % of base material strength. The average grain size of the repaired area can reach a minimum of 2.82 μm. The grain refinement degree of the side joint of the surface defect repair sample is higher than that of the bottom joint, and the corner joint of the bottom surface shows the highest proportion of recrystallized grains. Fracture locations were consistently within the interior of the repair zone in tensile specimens, indicating superior properties at side joints compared to those within the interior. The research proves that FRR has the ability to repair a variety of typical defects, including one-dimensional, two-dimensional and volume defects, in the process of processing and service, which lays a foundation for the industrial application of FRR.

Schrödinger cats coupled with cavities losses: the effect of finite and structured reservoirs

We discuss the generation of a Schrödinger cat in a nanocavity created by the coupling of an electromagnetic mode with an exciton in a quantum dot considering the dispersive limit of the Jaynes–Cummings model. More than the generation itself, we focus on the effects of the environment over the bosonic state in the nanocavity, which has losses simulated by coupling with two different kinds of reservoirs. In the first case, the interaction of the system with a finite reservoir shows that fragments of different sizes of the reservoir deliver the same amount of information about the physical system in the dynamics of the birth and death of the Schrödinger cat. The second case considers a structured reservoir, whose spectral density varies significantly with frequency. This situation becomes relevant in solid-state devices where quantum channels are embedded, as memory effects generally cannot be neglected. Under these circumstances, it is observed that the dynamics can differ substantially from the Markovian, presenting oscillations related to the average number of photons. These oscillations influence the information flow between the system and the environment, evidenced here by the measurement of non-Markovianity.

3D Terahertz Antenna Measurement: A comparison between solid-state electronics and photomixing approaches

3D Terahertz Antenna Measurement: A comparison between solid-state electronics and photomixing approaches

Cold spray - a solid-state additive manufacturing technology

Abstract Cold spray is a solid-state powder deposition technique and has evolved into an additive manufacturing process. Unlike conventional additive manufacturing technologies that rely on melting and solidification, cold spray additive manufacturing (CSAM) forms components at low temperatures at a relatively high build rate. This article introduces the technical principles, process parameters and typical microstructure of cold spray, as well as its applications in the fabrication of 3D components and damaged component repair. Current issues faced in cold spray research and future development directions in CSAM are also discussed.

Research on Breaking Function for Two Bidirectional Γ-Source DC Solid-State Circuit Breakers

Research on Breaking Function for Two Bidirectional Γ-Source DC Solid-State Circuit Breakers

Nanoconfined Supercooled Water in Hydrated Two-Dimensional Polyaniline for Sub-Zero Solid-State Zinc-Ion Hybrid Capacitor.

Solid-state electrochemical energy systems have attracted numerous attentions for their excellent performance, high safety, and low cost. Recently, ice of aqueous electrolytes is reported as a new kind solid-state electrolyte for low-temperature solid-state devices. However, the lack of kinetically favorable electrodes hampers the performance of this new class of icy electrolyte-based solid-state devices at sub-zero temperatures. In this work, a hydrated layered polyaniline cathode active material (h-LPANi) with nanoconfined supercooled water by metatungstate clusters is utilized to improve the performance of sub-zero solid-state zinc ion hybrid capacitors (ZIHCs). The interlayer confined hydrated network of h-LPANi improves kinetics, surpassing pristine polyaniline and conventional porous carbon-based active materials. At -15°C, the solid-state iced ZIHCs with h-LPANi cathode demonstrate an areal energy density of 580.0µWhcm-2 at 1.1mWcm-2 and 155.7µWhcm-2 at 43.3mWcm-2, surpassing other low-temperature solid-state ZIHCs with conventional cathodes.

Optimization and luminescence studies of Sm3+ doped LiCaBO3 phosphors for high-performance white light-emitting diodes

An undoped and a series of orange-red emitting LiCaBO3:Sm3+ (x = 0.5–3 mol%) phosphors have been synthesized using a highly reliable and cost-effective combustion method. The synthesized phosphors were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL), and Diffuse Reflectance spectroscopy (DRS). The structural studies of the LiCaBO3:Sm3+phosphor confirm the single-phase orthorhombic structure with space group Pbca and the presence of borate anionic groups. Upon near-UV excitation at 405 nm, the PL emission spectra show four emission peaks centered at 564 nm, 602 nm, 650 nm, and 708 nm corresponding to the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions respectively resulting in the emission of orange-red light. The optimum dopant concentration of Sm3+ion was 1 mol% and the main mechanism of concentration quenching was calculated using Dexter's theory. The bandgap of the undoped phosphor was found to be 5.31 eV. The CIE chromaticity coordinates are (0.56, 0.40) which confirms the orange-red emission. The obtained results indicate that the synthesized phosphor can be a potential candidate for application in solid-state lighting devices.

Terbium (III) and salicylamide doped nickel ferrite (NiFe2O4) nanoparticles synthesized from Olea europaea L. plant extracts via eco-friendly green synthesis approach and co-precipitation method

An eco-friendly and cost-effective NiFe2O4 nanoparticles and its derivatives NiFe2O4:salicylamide, NiFe2O4:salicylamide:Tb3+ and NiFe2O4:salicylamide:Tb3+:Olea europaea L. extracts have been successfully synthesized using a simple and refluxed-assisted chemical co-precipitation method and green route approach followed by thermal treatment steps. In this report, the structural, morphological, optical characteristics and biological activities of the nanoparticles were characterized by using XRD, SEM, FTIR, UV-Vis, PL, BET analysis, antibacterial assays and antioxidant activities. The results from XRD revealed that NiFe2O4 has a crystalline structure and EDX elemental mapping confirmed the uniform distributed of all the elements in the matrix. The incorporation of salicylamide, Tb3+ and Olea europaea L. extracts into NiFe2O significantly enriched the luminescence intensities and changed the emission colour coordinates. Colour tunability was achieved with luminescence ranging from bright blue emission to reddish orange light, which makes nanoparticles important candidates for solid-state lighting technologies. Combining olive leaf extracts with NiFe2O4 nanoparticles provided effective antioxidant and antibacterial activity by reducing and stabilizing of nanoparticles. Moreover, all experimental results reveal new ideas for the design and optimization of multifunctional nanomaterials with higher sensitivity and pave the way for the production of new functional nanomaterials.

Designed 2D protein crystals as dynamic molecular gatekeepers for a solid-state device

The sensitivity and responsiveness of living cells to environmental changes are enabled by dynamic protein structures, inspiring efforts to construct artificial supramolecular protein assemblies. However, despite their sophisticated structures, designed protein assemblies have yet to be incorporated into macroscale devices for real-life applications. We report a 2D crystalline protein assembly of C98/E57/E66L-rhamnulose-1-phosphate aldolase (CEERhuA) that selectively blocks or passes molecular species when exposed to a chemical trigger. CEERhuA crystals are engineered via cobalt(II) coordination bonds to undergo a coherent conformational change from a closed state (pore dimensions <1 nm) to an ajar state (pore dimensions ~4 nm) when exposed to an HCN(g) trigger. When layered onto a mesoporous silicon (pSi) photonic crystal optical sensor configured to detect HCN(g), the 2D CEERhuA crystal layer effectively blocks interferents that would otherwise result in a false positive signal. The 2D CEERhuA crystal layer opens in selective response to low-ppm levels of HCN(g), allowing analyte penetration into the pSi sensor layer for detection. These findings illustrate that designed protein assemblies can function as dynamic components of solid-state devices in non-aqueous environments.

Unveiling a giant electrocaloric effect at low electric fields through continuous phase transition design

The reported electrocaloric (EC) effect in ferroelectrics is poised for application in the next generation of solid-state refrigeration technology, exhibiting substantial developmental potential. This study introduces a novel and efficient EC effect strategy in (1–x)Pb(Lu1/2Nb1/2)O3-xPbTiO3 (PLN-xPT) ceramics for low electric-field-driven devices. Phase-field simulations provide fundamental insights into thermally induced continuous phase transitions, guiding subsequent experimental investigations. A comprehensive composition/temperature-driven phase evolution diagram is constructed, elucidating the sequential transformation from ferroelectric (FE) to antiferroelectric (AFE) and finally to paraelectric (PE) phases for x=0.10−0.18 components. Direct measurements of EC performance highlight x=0.16 as an outstanding performer, exhibiting remarkable properties, including an adiabatic temperature change (ΔT) of 3.03 ​K, EC strength (ΔT/ΔE) of 0.08 ​K ​cm kV−1, and a temperature span (Tspan) of 31 ​°C. The superior EC effect performance is attributed to the temperature-induced FE to AFE transition at low electric fields and diffusion phase transition behavior contributing to the wide Tspan. This work provides valuable insights into developing high-performance EC effect across broad temperature ranges through the strategic design of continuous phase transitions, offering a simplified and economical approach for advancing ecofriendly and efficient solid-state cooling technologies.

Enhancing capacitive performance of MoS2 through Fe doping: Synthesis, characterization, and electrochemical evaluation for supercapacitor applications

The capacitive performance of bare MoS2 is limited due to its poor electronic conductivity. Therefore, we tried to dope different weight percentages (2 %, 4 %, 6 %, 8 %, and 10 %) of Iron (Fe) into the MoS2 to promote more active sites to improve its energy storage capacity. Given this, we have synthesized bare MoS2 and Fe-doped MoS2 using the hydrothermal method for electrochemical charge storage application. The effect of doping was well assessed using different physicochemical tests. The electrochemical properties of the bare MoS2 and Fe-doped MoS2 were evaluated using a three-electrode setup in a 3 M KOH aqueous electrolyte. As a result, the 8 % Fe-doped MoS2 electrode material demonstrates the maximum specific capacitance (CSP) of 545 F/g @ 1 A/g with 84.8 % capacitive retention over 2000 cycles at 5 A/g. Additionally, we fabricated an asymmetric solid-state supercapacitor device, which reveals a high CSP of 74.28 F/g at 4 A/g with an energy density of 72.79 Wh/kg and a power density of 10.07 kW/kg. The results asserted that the Fe-doped MoS2 is a potential electrode material for supercapacitor application.

“Unveiling marigold assembled micro flowers of tungsten oxide towards solid-state flexible pouch and coin cell supercapacitors”

Marigold analogues micro flowers of tungsten oxide (WO3) have been grown in thin film form through simple and cost-effective solution chemistry approach on stainless steel substrate. Aqueous precursor involving WO4-2 ions agglomerated as self-sacrificing template growing initially into the nano-petal, followed by self-assembly; leading to marigold analogues micro flower surface architecture. This enthralling morphology motivated us not only to fabricate supercapacitive electrode but also to design complete solid-state supercapacitor devices in dual configurations: flexible pouch cell and coin cell. Interestingly, both devices even in symmetric configuration yields remarkable potential window of 1.82 V when sandwiched by gel inclusive of Li+ ions dispersed in non-conducting polyvinyl alcohol matrix. Solid-state flexible pouch cell and coin cell delivered specific capacitances of 103.98 ± 3.59 and 30.09 ± 1.03 F/g respectively at a scan rate of 5 mV/s. Assembled electrode, coin-cell and flexible pouch-cells have been well assessed in-depth through specific capacitances using cyclic voltammetry and galvanostatic charge discharge, diffusive and capacitive contributions, mechanical bending tests, electrochemical active surface area, and electrochemical impedance analysis. Practical applicability has been demonstrated for designed flexible pouch cell to run small fan and light emitting diode panel whereas coin cell to run light emitting diode panel.

Immunological assay using a solid-state pore with a low limit of detection

Emerging infectious diseases, cancer, and other diseases are quickly tested mainly via immune reactions based on specific molecular recognition between antigens and antibodies. By changing the diameter of solid-state pores, biomolecules of various sizes can be rapidly detected at the single-molecule level. The combination of immunoreactions and solid-state pores paves the way for an efficient testing method with high specificity and sensitivity. The challenge in developing this method is achieving quantitative analysis using solid-state pores. Here, we demonstrate a method with a low limit of detection for testing tumor markers using a combination of immunoreactions and solid-state pore technology. Quantitative analysis of the mixing ratio of two and three beads with different diameters was achieved with an error rate of up to 4.7%. The hybrid solid-state pore and immunoreaction methods with prostate-specific antigen (PSA) and anti-PSA antibody-modified beads achieved a detection limit of 24.9 fM PSA in 30 min. The hybrid solid-state pore and immunoreaction enabled the rapid development of easy-to-use tests with lower limit of detection and greater throughput than commercially available immunoassay for point-of-care testing.

Boosting room-temperature electrocaloric performance in B-site complex antiferroelectrics: A synergistic design approach

As an emerging eco-friendly solid-state refrigeration technology boasting high energy conversion efficiency, there is a pressing demand for ferroelectrics exhibiting significant electrocaloric effect (ECE) at room temperature (RT) for refrigeration applications. In this study, guided by phase-field simulation, we explore the potential of B-site complex Pb[Mg(1–x)ZnxW]1/2O3 (PMZW100x) antiferroelectrics (AFE) to deliver promising symmetric positive and negative ECE near ambient temperature. The first-order AFE-paraelectric (PE) phase transition occurring around 50 °C induces a substantial change in heat quantity and yields prominent ECE upon electric excitation. Maxwell characterization reveals a potential combination of positive and negative ECE, showcasing significant advantages in cooling capacity. Given the technical limitations of existing direct methods for testing under elevated electric fields, low-field ECE is validated using the heat flux approach to ensure the legitimacy of results. Direct measurements demonstrate a high positive ΔT value of 2.76 K at 52 °C and a negative ΔT of –2.91 K at 44 °C (under 140 kV cm–1), surpassing traditional PbZrO3 bulk materials. The coexistence of substantial positive and negative ΔT near RT in PMZW100x offers a new avenue for developing highly efficient solid-state cooling devices.

Loss and decoherence in superconducting circuits on silicon: Insights from electron spin resonance

Solid-state devices used for quantum computation and quantum sensing applications are adversely affected by loss and noise caused by spurious, charged two-level systems (TLS) and stray paramagnetic spins. These two sources of noise are interconnected, exacerbating the impact on circuit performance. We use an on-chip electron spin resonance (ESR) technique, with niobium nitride (NbN) superconducting resonators, to study surface spins on silicon and the effect of postfabrication surface treatments. We identify two distinct spin species that are characterized by different spin-relaxation times and respond selectively to various surface treatments (annealing and hydrofluoric acid). Only one of the two spin species has a significant impact on the TLS-limited resonator quality factor at low-power (near-single-photon) excitation. We observe a three- to fivefold reduction in the total density of spins after surface treatments and demonstrate the efficacy of ESR spectroscopy in developing strategies to mitigate loss and decoherence in quantum systems. Published by the American Physical Society 2024

Process intensification of microwave-assisted freeze-drying by frequency adjustment in real-time using solid-state technology

In microwave-assisted processes, solid-state microwave technology enables control of the electromagnetic field, which can be used for process intensification. This work investigates the impact of real-time frequency adjustment on microwave-assisted freeze-drying (MFD). Frequency-based control concepts were applied in experiments with tylose gel as a food model product in a laboratory-scale plant. By applying energy-efficient resonant frequencies based on feedback related to product state, the drying time was reduced by 24.2% compared to conventional freeze-drying (CFD) due to increases in energy efficiency. Comparable temperature profiles, residual moistures, and ascorbic acid retentions to CFD were achieved. However, structural degradation occurred with MFD in up to 10.4% of the samples. The degradation could be counteracted by more refined frequency and power application. In summary, this work demonstrates the high potential of frequency-based control for MFD process intensification.

Rational design of hybrid electrolyte for all-solid-state lithium battery based on investigation of lithium-ion transport mechanism

Lithium all-solid-state batteries (ASSBs) are a promising technology for achieving high energy density, long cycle life, and safe rechargeable battery systems. Among these, Li ASSBs using solid polymer electrolytes (SPEs) have gained attention owing to their processability, lightweight nature, flexibility, and favorable electrode contacts. However, SPEs have low ionic conductivity, low Li+ transference number, and lack mechanical strength, limiting cell performance. Therefore, the present study focuses on the development of hybrid polymer electrolytes (HPEs) by incorporating Li1+xAlxTi2-x(PO4)3 (LATP) of Li/Na superionic conductor-type materials into SPEs. The HPEs with LATP 10 wt% exhibited significant improvements with an ionic conductivity of 7.23 × 10−4 S cm−1 at 45 °C and a Li+ transference number of 0.61. Density functional theory calculations supported the enhanced Li-ion migration through the polymer-LATP interface achieved by the optimized LATP content. The addition of LATP particles enhanced the mechanical strength of the electrolytes, effectively suppressing dendrite growth, resulting in a 66.65 % capacity retention after 320 cycles, highlighting the crucial role of high-performance HPEs in advanced ASSBs. By addressing the limitations of SPEs, HPEs offer promising opportunities to unlock the full potential of solid-state battery technologies for various energy storage systems.

Donor-acceptor bulk-heterojunction sensitizer for efficient solid-state infrared-to-visible photon up-conversion

Solid-state infrared-to-visible photon up-conversion is important for spectral-tailoring applications. However, existing up-conversion systems not only suffer from low efficiencies and a need for high excitation intensity, but also exhibit a limited selection of materials and complex fabrication processes. Herein, we propose a sensitizer with a bulk-heterojunction structure, comprising both an energy donor and an energy acceptor, for triplet-triplet annihilation up-conversion devices. The up-conversion occurs through charge separation at the donor-acceptor interface, followed by the formation of charge transfer state between the energy donor and annihilator following the spin statistics. The bulk-heterojunction sensitizer ensures efficient charge generation and low charge recombination. Hence, we achieve a highly efficient solid-state up-conversion device with 2.20% efficiency and low excitation intensity (10 mW cm−2) through a one-step solution method. We also demonstrate bright up-conversion devices on highly-flexible large-area substrates. This study introduces a simple and scalable platform strategy for fabricating efficient up-conversion devices.

Study on the hydrate growth characteristics and rheology of silica-containing sand water-in-oil emulsion system

Understanding the transportability of silica-sand-containing hydrate slurries is crucial for production safety of non-consolidated natural gas hydrate reservoirs, especially when solid-state fluidization technology is utilized. Despite some research on silica sand and marine sediments’ influence on hydrate formation kinetics, rheological studies are scarce for systems with silica sands. The formation process of cyclopentane hydrates under the coexistence of hydrophilic silica particles and surfactants were observed. The effects of the concentration and particle size of silica sands as well as the water cut and surfactant concentration of emulsion on the rheological properties of hydrate slurries were investigated using a rheometer. The results indicated: (1) Hydrophilic sand aggregates were entrapped in water droplets, indirectly affecting the oil–water contact area due to the increase in water droplet volume, which was conducive to the combination of alkanes and water molecules to form a hydrate shell; silica particles provided nucleation sites at the oil–water interface to promote the adsorption and aggregation of cyclopentane molecules. (2) The synergistic effect of silica sand and surfactants significantly shortened the induction time of hydrates and increased the viscosity of the slurry. As the concentration of silica sand (1 wt%, 5 wt%, 10 wt%) increased, the induction time of hydrate formation decreased by 44.8 min. Within the concentration range below 5 wt%, the viscosity of the slurry increased as the concentration increased, with an amplitude of 13830.7 mPa·s. The induction time of hydrate formation decreased with increasing silica sand particle size (2 μm, 6.5 μm, 12 μm), but the size of silica sand particles had no significant effect on the viscosity of the slurry. (3) Hydrate slurries in all systems exhibited shear-thinning behavior. There was no obvious relationship between the yield stress of slurry under different silica sand concentrations. However, the yield stress of the slurry was inversely proportional to the size of silica sand particles. The yield stress decreased by 141.13 Pa when the size of silica sand particles increased from 2 μm to 12 μm. Overall, this study highlighted the influence of silica sand presence on flow safety assurance in solid-state fluidization technology.