Objective Traditional optical lenses face significant challenges in miniaturization and system integration due to limitations in refractive index modulation capabilities and chromatic aberration correction techniques. Optical metasurfaces are artificial structures composed of subwavelength units arranged in specific patterns. By adjusting the size and arrangement of these structural units, unprecedented modulation of the phase, amplitude, and polarization of electromagnetic waves can be achieved. With its remarkable advantages of ultra-thin profile, lightweight construction, and ease of integration, the metasurface lens has emerged as a revolutionary planar lens technology. However, achromatic designs for metamaterials in the visible spectrum face dual challenges: strong dispersion and structural resonance. The emergence of scintillator materials in X-ray imaging offers a new opportunity to resolve this conflict. These materials absorb X-rays and emit narrow-band visible light with a full width at half maximum (FWHM) below 20 nm, achieving near-monochromatic emission under specific processes. The narrow-band characteristics of such light sources inherently suppress focal shift and resolution degradation caused by chromatic aberration, enabling optical components to be applied in X-ray detection without complex broadband achromatic designs. We proposed an embedded hemispherical cylindrical metalens design, achieving 87.78% focusing efficiency at the 530 nm peak wavelength of perovskite bromine?lead?cesium quantum dots. This is attributed to the hemispherical structure's ability to excite higher-order Mie scattering modes, generating enhanced localized electric fields at the nano-unit/substrate interface. This results in five percentage points increase in average transmittance compared to conventional structures across the 480?580 nm wavelength range. Furthermore, the hemispherical design effectively reduces defects such as coating voids, improving yield and enabling device fabrication. The metalens array can be fabricated and integrated with CMOS detectors in the future to get high-resolution X-ray imaging detection devices. Methods The micro-nano structure selected in this study is a sphere-cylinder composite structure. Serving as the basic unit of the metalens, this structure consists of a SiO2 substrate, a TiO2 cylinder, and a hemisphere, with the detector integrated inside the SiO2 substrate. The period of the unit structure is set to 520 nm; the radius ranges from 50 nm to 150 nm; the height varies between 0.5 mu m and 1.5 mu m, and the operating wavelength is configured in the 480-580 nm band. To achieve full phase coverage, the height of the cylinder is finally determined to be 0.8 mu m after comprehensively balancing the phase modulation capability and transmittance. This structure was compared with metalenses of two other structures: one is a semi-embedded cylindrical structure with a height of 0.8 mu m and an embedding depth of 0.1 mu m; the other is a pure cylindrical unit structure with a height of 0.9 mu m. All three metalenses were designed using the propagation phase modulation method, and the finite-difference time-domain (FDTD) simulation was employed to calculate the focal length of the metalenses and the focusing efficiency at the focal point under different radii. Results and Discussions The FDTD simulation results show that the focusing efficiency of this metalens reaches 87.78% at a wavelength of 530 nm, with a FWHM of 643.71 nm and a transmittance exceeding 80%. Within the 480?580 nm wavelength band, the average focusing efficiency of the hemispherical structure is 81.94%, which is approximately five percentage points higher than that of the traditional cylindrical structure (76.90%) and the semi-embedded cylindrical structure (77.01%). This advantage is attributed to the embedded hemispherical design, which enhances the localization of the optical field and reduces modal loss. Further analysis indicates that by optimizing the refractive index matching between the substrate and the nanostructure, the hemispherical structure achieves stable focusing performance in the 480?580 nm band. When used in combination with a narrow-band scintillator (e.g., emission wavelength of 12 nm), the focal shift can be controlled within 1.2 mu m, effectively suppressing chromatic aberration. In terms of optical field distribution, the far-field light intensity concentration of the hemispherical structure is significantly superior to that of the other structures, and the fluctuation range of the FWHM of its Airy disk is only +/- 4 nm, verifying the diffraction-limited focusing capability of this design. Conclusions We propose a visible-light polarization-insensitive metamaterial-based metalens design, featuring a core structure comprising cylindrical TiO2 nanocolumns on a SiO2 substrate and a hemispherical TiO2 atomic array within the substrate. By adjusting the radius and height of the nanostructures, full coverage of 0?2 pi phase delays is achieved. FDTD simulations reveal that this structure achieves a focusing efficiency of 87.78% at a wavelength of 530 nm, with a FWHM of 643.71 nm and a transmittance exceeding 80%. A comparison among the cylindrical structure, semi-embedded cylindrical structure, and embedded hemispherical structure reveals that the hemispherical structure achieves an average focusing efficiency of 81.94% in the 480?580 nm wavelength band, approximately five percentage points higher than the 76.90% of the traditional cylindrical structure and the 77.01% of the semi-embedded structure. This advantage stems from the enhanced optical field localization and energy coupling efficiency enabled by Mie scattering. When combined with a narrow-band scintillator with an emission range of only 12 nm, the focal shift is merely 1.2 mu m, which effectively suppresses the focal drift caused by chromatic aberration.In terms of fabrication process, the introduction of the hemispherical structure can reduce defects such as coating holes and improve the yield rate. This metalens demonstrates great potential in super-resolution imaging (with a numerical aperture NA=0.44), X-ray detection, and integrated optical systems. In the future, efforts will be made to optimize the integration of detection systems, so as to promote its practical application in the next-generation X-ray imaging technology.

The systematic influence of signal electrode width on electro-optic bandwidth and insertion loss in L-type traveling-wave lithium niobate modulators has not yet been comprehensively quantified, limiting the parametric engineering design of this device configuration. This study presents a full-band systematic simulation sweep of signal electrode width and three auxiliary geometric parameters in an L-type traveling-wave lithium niobate Mach-Zehnder modulator, combined with optical mode simulation to establish joint microwave-optical optimization constraints. The study reveals the coupled modulating effect of signal electrode width on characteristic impedance, velocity mismatch, and transmission loss; it elucidates the competition mechanism underlying non-monotonic high-frequency loss behavior; and it identifies the complete impedance-neutral characteristic of the electrode-waveguide contact width as an independent loss-tuning degree of freedom decoupled from the impedance constraint. Full-system validation confirms that the final design simultaneously satisfies broadband impedance matching, low insertion loss, and high electro-optic bandwidth. The results are distilled into four quantitative design rules that provide simulation-driven guidance directly applicable to the engineering design of L-type thin-film lithium niobate modulators, advancing the systematic establishment of a parametric design methodology for this device configuration.

The development of perovskite oxide epitaxial films and their freestanding membranes for the next-generation integrated and miniaturized electronics has attracted a lot of attention due to their promising multiferroic properties and low dimensionality. Strontium titanate, (SrTiO3, STO), as one typical perovskite incipient ferroelectric materials, has been reported to encounter significant challenges in inducing stable ferroelectricity and magnetism at room temperature, especially in the case of freestanding STO membranes. Here we deliberately introduced Ti deficiency/O-vacancy into the targeted STO thin films via defect-strain engineering to prepare the non-stoichiometric epitaxial thin films with large Sr/Ti ratios. The prepared non-stoichiometric STO thin films (Sr/Ti = 0.6/0.4) exhibited stable tetragonal phase with coexistent relaxor ferroelectricity and magnetism, which was thought to be associated with the presence of polar nanoregions. Importantly, owning to the defect-strain engineering, the freestanding non-stoichiometric STO membranes well preserved the initial compressive strain state when releasing from the rigid substrate. The freestanding STO membranes thus exhibited a polar tetragonal phase with significant ferroelectricity and magnetism. This study offers an effective approach for achieving ferroelectricity and magnetism in STO materials, both for epitaxial thin films and freestanding membranes, which gives their great potential in multifunctional semiconductor applications.

Aiming at the uneven thermal distribution caused by parasitic parameter mismatch in multiphase Buck converters, and the problems of discontinuous high efficiency region and output fluctuation caused by coarse switching granularity in traditional binary phase shedding, a high efficiency multiphase converter based on 180nm BCD process is proposed in this paper. A fine-grained dynamic phase shedding control (DPSC) scheme with offset rotation strategy is newly presented, which uses linear integer step regulation to overcome transient shocks of traditional switching and broadens the high-efficiency zone. For the localized aging caused by fixed phase operation in traditional phase shedding, the offset rotation mechanism is introduced to realize thermal stress time-domain average sharing, and the thermal sensing mechanism is integrated to actively avoid the high temperature phase. Simulation results show that the converter achieves a peak efficiency of 95% under 0.1A-15A load, and the efficiency is not less than 90% in the 0.15A-10A core interval.

All-dielectric metasurfaces based on quasi-bound states in the continuum (quasi-BICs) have emerged as a powerful platform for nanophotonic sensing, as they support high-Q resonances and strong near-field enhancements. Herein, we propose and numerically investigate an asymmetric bow-tie metasurface composed of two silicon semi-cylinders with unequal radii and a central bar to achieve a quasi-BIC resonance with a Q-factor of 11,000. The transition mechanism of the BIC modes in the asymmetric bow-tie metasurface is analyzed. Additionally, the spectral features of the asymmetric bow-tie metasurface as a function of the refractive index and temperature of the local environment are also investigated. The proposed structure exhibits a refractive index sensitivity of 454 nm/RIU and a temperature sensitivity of 134 pm/°C. Furthermore, a high figure of merit (FOM) of 3159 RIU−1 is achieved, and the nearly 100% modulation depth maintained across three distinct resonance dips. Our study suggests that the proposed asymmetric bow-tie metasurface offers a promising approach for the development of high-sensitivity biosensing platforms.

Traps at the semiconductor-oxide interface are considered as a major source of instability in semiconductor quantum devices, yet the quantified study of their cryogenic behavior remains limited. In this work, we introduce a transferrable workflow to model the impact of interface states on these devices. This method combines transport measurement with Schr & ouml;dinger-Poisson simulation and tunneling analysis, and is potentially compatible to different quantum wells (QWs). By demonstrating this workflow experimentally on a practical Ge/SiGe Hall-bar field-effect transistor device, we successfully reconstruct the gradual filling process of interface states and suggest a crossover in the tunneling-trapping process from trap-assisted-tunneling- to Fowler-Nordheim (F-N)-tunneling-involved transport, which refines the conventional F-N-based picture of interface trapping. Our workflow shows the potential of studying cryogenic interface states on different QWs, as well as provide guidelines for enhancing Ge-based quantum device performance by improving barrier crystalline qualities and reducing dislocation-related trap densities.

This study presents a low‑power discrete‑time (DT) level‑crossing (LC) ADC for biopotential signal measurement in wearable instrumentation. The design employs a hardware-reuse technique that time-multiplexes a single 7-bit CDAC for both coarse LC tracking and fine SAR quantization, thereby eliminating the need for separate DACs. Two-stage LC detection with programmable second-stage windows improves capture of fine signal variations without hardware overhead. Fabricated in 180 nm BCD, the 0.0896 mm² prototype achieves a peak SNDR of 67.6 dB (10.94-bit ENOB) at 100 Hz and maintains 61.2 dB SNDR (9.87-bit ENOB) at a full 20 kHz bandwidth. Full-bandwidth operation consumes 4.68 μW (59.7 fJ/conv.-step); the efficiency improves at lower frequencies to 27 fJ/conv.-step, and the power drops to 0.79 μW for sparse biological signals, demon-strating its suitability for energy-constrained wearable instrumentation.

Hole-phonon interactions play an important role in transport and decoherence processes in semiconductor quantum dots. Here we investigate hole-phonon coupling in a gate-defined GaAs double quantum dot integrated with a quantum point contact charge sensor. Under finite source-drain bias, pronounced oscillatory stripe patterns appear near specific charge transition regions in the charge stability diagram. We attribute these oscillations to phonon emission during inelastic interdot tunneling. A theoretical model including piezoelectric hole-phonon coupling reproduces the observed patterns. Furthermore, our analysis shows that the oscillations emerge only in particular charge configurations. Our results provide direct insight into phonon-assisted transport and coherent hole-phonon interactions in semiconductor quantum dots.

To meet the diverse requirements of integrated chips for application scenarios such as AI and ML, this study focus on core work including Si NMOS P-well doping/GaN integration co-design, GaN device modeling, and buck heterogeneous circuit verification, and for the first time validates the feasibility of material-process-circuit monolithic GaN /Si CMOS heterogenous integration. A comprehensive SPICE model for the system is established using the ASM-HEMT, with error RMS of 2%, supporting circuit co-design. Finally, compared with all-GaN and all-Si integrated circuit technologies, the co-designed GaN/Si CMOS heterogenous buck converter (12 V to 5 V) achieves higher integration density (area reduced from 1.94 mm2 to 0.023 mm2 compared with all-silicon), lower loss (reduced from 752 mW to 183 mW compared with all-GaN), and full utilization of GaN switching-speed advantages. Results show the proposed power stage prototype performs excellently in power density, switching frequency, and energy conversion efficiency, further verifying better flexibility and innovation than 3D integration for heterogeneous chip design.

Scalability represents a fundamental challenge in advancing semiconductor-based quantum computing architectures. Germanium nanowires (NWs) have emerged as a highly promising platform due to their demonstrated high-quality in-plane NW networks. In this study, we demonstrate the fabrication of two distinct sets of multiple quantum dots (QDs) on closely spaced parallel Ge hut wires. Charge sensing is achieved through capacitive coupling between the two sets of QDs. Furthermore, the tunability of both sets of QDs enables mutual detection between dot pairs across arrays. Through systematic gate voltage adjustments, we successfully transition the system configuration from a single quantum dot (SQD) to triple quantum dot (TQD) regimes. We identify edge state impurities in one set of QDs, which may introduce crosstalk effects and potentially hinder qubit detection and manipulation. Through comprehensive analysis and numerical simulations of these edge states, we hope to develop approaches to avoid the formation of such edge state impurities in the future.

This paper proposes an advanced 0.15μm 120 V P-epi BCD technology platform applied for automotive applications. The 60-120 V n/p LDMOS adopts controllable RESURF technology and deep drain profile engineering, achieving best in class breakdown voltage (BV) & specific on-resistance (Ron,sp) of 146 V/155 mOhm*mm2, and maintaining high safe operating area (SOA) performance from -40 °C to 125 °C. The deep trench isolation (DTI) is used to suppress latch-up and reduce noise coupling, which significantly reduces the injection ratio (α) of the parasitic PNP from 0.93 to 0.41 and the current gain (β) of the parasitic NPN from 47 to 3.49. On the other hand, a novel composite PNP-based ESD (CPNP-ESD) is proposed to improve the capability of the failure current (IT2), which constructs a composite current path combining lateral and vertical paths by removing the HVNW, and thereby effectively mitigates surface current crowding. The base structure is designed to tune trigger voltage (VT1) and holding voltage (Vh) by modulate PNP current gain. It achieves an IT2 exceeding 3 A at 25 °C and 2.5 A at 125 °C, maintains a stable holding voltage (Vh), and significantly reduces the latch-up risk.

This letter presents a millimetre-wave continuously tunable reflection-type phase shifter (RTPS) using a 0.25 & micro;m GaAs process targeting the n258 band of 5G communication. A wider than 180 degrees phase shift range is provided, while superior in-band phase flatness with low-loss performance is achieved. The circuit consists of a 90 degrees Lange coupler and a pair of reflective loads where a multi-resonance structure and schottky diode varactors are employed. Compared to conventional switch-type phase shifters using the GaAs process, the RTPS proposed only requires one bias voltage adjustment to achieve wide-range continuous phase shifting without DC power consumption. The proposed has a 187 degrees phase shift range and 6.6 dB average insertion loss over the 24-28 GHz. A machine-learning-based calibration model is further introduced to learn the phase-voltage mapping from simulated/measurement data, enabling fast digital phase predistortion and reducing calibration effort in phased-array control.

Abstract Spin qubits based on semiconductor quantum dots have recently emerged as strong candidates for scalable quantum computation. However, due to substantial charge noise in the system, the coherence time remains insufficient to support large-scale quantum computations. Moreover, the fidelity of idle gates is severely degraded by the short dephasing time, which may compromise the overall quality of full quantum algorithms. Here, we demonstrate a circular-modulated concatenated continuous driving (CM-CCD) qubit realized in $^{28}$Si metal-oxide-semiconductor (SiMOS) devices to overcome this challenge. This scheme significantly enhances the qubit's resilience to noise and substantially improves its coherence: the dephasing time $T_{2}^{*}$ is extended from $717.7\ \text{ns}$ to $101.5\ \mu\text{s}$, and the Rabi coherence time $T_{2}^{\text{Rabi}}$ is improved from $7.8\ \mu\text{s}$ to $77.6\ \mu\text{s}$. We further propose a scheme to resolve the timing misalignment of CCD-based idle gates, improving the idle gate fidelity from 95.95% to 99.01%. Collectively, these results demonstrate that the CCD scheme offers a promising pathway to overcome the idle-gate challenge in large-scale quantum computations.

Semiconducting carbon nanotubes (CNTs) exhibit exceptional electrical properties, making them highly promising candidates for conductive channel materials in the post-Moore era. However, enhancing the gate control capability of CNT-based transistors remains a critical research challenge, as it is essential for building high-performance, low-power CNT transistors. Zirconium-doped hafnium oxide (HZO), a high-k gate dielectric material with excellent ferroelectric properties, enables transistors to surpass the 60 mV/dec subthreshold swing limit through its negative capacitance effect. In this study, HZO ferroelectric thin films were fabricated using atomic layer deposition, and CNT conductive channel layers were prepared via solution deposition, resulting in a novel CNT-based negative-capacitance transistor. The device demonstrated outstanding electrical performance, including an on/off current ratio of 107, a subthreshold swing of 58 mV/dec, and an operating voltage below 0.5 V. Compared to traditional silicon-based field-effect transistors (FETs), this thin-film transistor exhibits significantly reduced power consumption. In addition, logic gate circuits based on the proposed HZO-CNT FET were further designed and simulated, demonstrating the feasibility of utilizing this device for low-power logic-function applications. The CNT-based HZO ferroelectric gate dielectric transistor studied in this work provides a promising platform for exploring future low-power electronic devices and integrated circuit applications.

In this study, (In x Ga1-x )(2)O-3 f thin films with varying indium contents were fabricated using a novel mist chemical vapor deposition (Mist-CVD) method equipped with a dual-precursor ultrasonic atomization system. This newly proposed Mist-CVD technique enables independent control of the carrier gases for Ga and In precursors, thereby overcoming the limitations of conventional single-precursor systems in tuning elemental composition. The resulting (In x Ga1-x )(2)O-3 films exhibited tunable In contents ranging from 0.05 to 0.20, corresponding to bandgaps between 4.62 eV and 4.30 eV. Characterization results showed that the film with x = 0.11 had the best crystallinity. To verify the feasibility of these films for optoelectronic applications, MSM ultraviolet photodetector was fabricated based on the (In 0.14 Ga 0.86 )(2)O-3 film demonstrating basic photoelectric performance, with a dark current of 0.86 nA,I- 254nm / I-dark ratio of 1.16x10 4 , and a responsivity of 0.52 A/W under a 12 V bias. These results indicate that the (In x Ga1-x )(2)O-3 films fabricated using the novel Mist-CVD system hold great potential for the scalable manufacturing of high-performance deep-ultraviolet optoelectronic devices.

Two-dimensional (2D) materials, with their rich electronic states and unique layered structure, hold promise for low-energy-consumption ionic memristors to advance high-performance artificial neural systems, yet challenges in large-area integration and stability remain. Here, a vertical heterostructure memristor with an Ag/ZnO/Si/MoS2/Mo/Au configuration was fabricated by directly growing MoS2 on the bottom electrode, enabling scalable fabrication of high-density devices. The memristor exhibits exceptional resistance switching stability and low operating voltages (V-SET approximate to 0.41 V, V-RESET approximate to -0.17 V), attributed to the ZnO interlayer acting as an ion migration barrier that efficiently restricts Ag ion diffusion and suppresses random conductive filament formation. Importantly, these properties enable the device to precisely mimic biological synaptic processes, including long-term potentiation/inhibition and paired pulse facilitation, while demonstrating incredibly low operational energy consumption (similar to 2.1 fJ/(mu m(2)x mu S)). The successful implementation of handwritten digit recognition further highlights the promising capabilities of this device in neuromorphic computing applications. This work presents an innovative concept for the development of a 2D material heterostructure memristor neural system with high integration, stability and low power consumption.

An electronically reconfigurable folded transmitarray antenna (RFTA) with wideband and wide-angle beam-scanning capacity is proposed. The RFTA is composed of a reconfigurable metasurface (RMS), a polarization conversion metasurface (PCMS), and a linearly polarized feed antenna. Each unit cell of the RMS is symmetrically integrated with two p-i-n diodes. By controlling the on-off state of the diodes, the RMS can perform two functions: 1-bit phase encoding and linear polarization conversion across a broad bandwidth (BW). The PCMS is a novel wideband polarization converter with stable polarization conversion performance for wide incident angle. The wideband performance of the RMS and PCMS endows the RFTA with wide-angle beam-scanning capacity over a broad frequency range. The experimental results demonstrate beam scanning over angles from -50 degrees to +50 degrees in the frequency range of 8.1 GHz to 11.3 GHz, with a peak gain of 15.93 dBi, a maximum aperture efficiency of 9.2%, and a 3 dB gain bandwidth of 33%.

Frequency tuning enables both high-sensitivity and wide-bandwidth detection in the resonator. Potassium tantalate (KTO) is a quantum paraelectric with tunable permittivity and low microwave loss at cryogenic temperature, making it promising for tunable devices. Here, we demonstrate a superconducting microwave resonator on a KTO substrate. The resonant frequency can be tuned by ∼40 MHz using a 9 V bias at 20 mK, with no observable hysteresis. The absence of hysteresis is a key metric for practical devices, addressing one of the major obstacles in other paraelectric-based tunable resonators. More interestingly, we observed that the quality factor oscillates during voltage tuning, arising from the competition between phonon hardening and charge injection. Therefore, our work provides a practical tunable resonator platform and offers a potential approach to study energy-loss characteristics in quantum paraelectrics.

Traps at the semiconductor-oxide interface are considered as a major source of instability in strained Ge/SiGe quantum devices, yet the quantified study of their cryogenic behavior remains limited. In this work, we investigate interface-state trapping using Hall-bar field-effect transistors fabricated on strained Ge/SiGe heterostructures. Combining transport measurements with long-term stabilization and Schrödinger-Poisson modelling, we reconstruct the gradual filling process of interface states at cryogenic condition. Using the calculated valence band profiles, we further evaluate the tunneling current density between the quantum well and the semiconductor-oxide interface. Our calculation demonstrates that the total tunneling current is consistent with a crossover from trap-assisted-tunneling-dominated transport to Fowler-Nordheim-tunneling-dominated transport under different gate bias regimes. These results refine the conventional Fowler-Nordheim-based picture of interface trapping in strained Ge/SiGe heterostructures and provide guidelines for improving Ge-based quantum device performance by improving barrier crystalline qualities and reducing dislocation-related trap densities.