Lead halide perovskites with the ABX₃ formula are limited by their small B-site ions, which hinder the incorporation of large ions into their three-dimensional BX₃ frame. Through high-throughput computational screening based on first-principle calculations and stringent structural constraints, we identified two promising candidates from 81 initial perovskites. These optimized materials feature a quasi-cubic, lead-free structure with a direct band gap suitable for solar cell applications, and minimal deformation of ions. The quasi-cubic (SCs₃)(CLi₆)F₃ superatom perovskite exhibit the direct band gap, s−p and p−p electron transitions, small carrier effective masses, and high efficiency. Additionally, (SCs₃)(CLi₆)F₃ superatom perovskite demonstrate N-type and P-type characteristics through occupying sulfur vacancies with Cl and P atoms, respectively, indicating that they may be used as electron and hole transport layers. This work implies the potential of superatom perovskites to overcome limitations of traditional perovskites.

Dual-band photodetectors represent one of the important development directions of the third-generation focal plane photodetectors. Type Ⅱ superlattice (T2SL) has emerged as a promising candidate for fabricating long-wavelength dual-band or multi-band infrared photodetectors due to its merits including engineerable band gap, low manufacturing cost and excellent uniformity. In this work, a long/long-wavelength dual-band photodetector with an NMπP-B-PπMN structure based on InAs/GaSb T2SL is reported. The cutoff wavelengths of the two bands are 7.8 and 11.2 μm, respectively. At 77 K, the short long-wavelength channel exhibits a peak quantum efficiency of 20.19%, a peak detectivity of 1.26 × 10¹⁰ Jones and dark current density of 0.91 × 10^–2 A/cm²; the long long-wavelength channel achieves a peak quantum efficiency of 28.94%, a peak detectivity of 7.36 × 10⁹ Jones and dark current density of 6.03 × 10^–2 A/cm². The device demonstrates high performance, laying a solid foundation for the fabrication of long/long-wavelength dual-band focal plane photodetectors.

InGaAs/InP single photon diodes (SPADs) are widely used in quantum communication systems. The dark count rate (DCR), which describes the noise level, is one of the most important parameters of SPAD performance. Here, we demonstrate the technology computer-aided design and experimental test of low DCR InGaAs/InP SPAD to be applicable to the fiber quantum key distribution system under high-frequency gating. In order to achieve a lower DCR at higher operating temperature, the device structure is optimized by increasing the doping concentration of the charge layer and expanding the width of the multiplier layer. At the same time, the charge persistence effect is limited by optimizing the double Zn diffusion process. The results show that our InGaAs/InP SPAD can achieve an extremely low DCR of 0.1 kcps, 30% photon detection efficiency and 4.7% afterpluse probability at an operating frequency of 1.25 GHz, an operation temperature of 213 K and an excess bias voltage of 4.6 V.

Bismuth-based oxides are well known for their high Curie temperature and excellent fatigue resistance, which have attracted extensive researches and various applications. In this work, we successfully fabricated pure phase α-Bi₂O₃ films by a novel ultraviolet ozone oxidation method from β-Bi. The obtained α-Bi₂O₃ exhibits room-temperature out-of-plane ferroelectricity, as confirmed by both piezoelectric force microscopy measurements and hysteresis loops obtained from out-of-plane ferroelectric tunnel junctions. Density functional calculations predict that the ferroelectricity of α-Bi₂O₃ arises from a synergistic interplay between electric-field-induced structural deformation and charge redistribution within films. Our results demonstrate that such a thin RT ferroelectric α-Bi₂O₃ film could be a promising candidate for future multifunctional electronic devices.

Germanium-on-silicon (Ge-on-Si) avalanche photodiodes (APDs) have attracted significant interest for LIDAR sensor applications over the last decade. However, further improvements are still needed to reduce dark current and excess noise while increasing the gain to fit the application requirements. Moreover, designing a good charge layer in separate absorption, charge and multiplication (SACM) structure for an APD is essential to control the electric field intensity in both the multiplication layer and germanium absorption layer. In this study, three different silicon charge layer thicknesses (80, 100, and 120 nm) and two boron doping concentrations of 2.5 $ \times $ 10¹⁷ and 5 $ \times $ 10¹⁷ at∙cm⁻³ were fabricated and characterized in vertical Ge-on-Si APDs. Our investigation focuses on the boron concentration of 2.5 $ \times $ 10¹⁷ at∙cm⁻³ to identify the physical contributions to current and noise at room temperature and a wavelength of 1550 nm. The device with a charge layer thickness of 80 nm exhibits the lowest equivalent input noise (NEI) of $ 1.7 {\mathrm{pA}}/\sqrt {\mathrm{{Hz}}} $ at a gain of 4.1, which is compatible with LIDAR application requirements. The results indicate that there may be an optimal combination of charge layer thickness and doping concentration for minimizing APD noise, which should be considered in future APD designs.

This work fabricates a vertical channel-all-around indium−gallium−zinc-oxide field-effect transistor(CAA IGZO FET) through reasonable etching process and annealing optimization. The resulting device exhibits has a normalized on-current (I_ON) of 87.1 μA/μm, and a subthreshold swing (SS) of approximately 66.98 mV/Dec. These performance parameters are twice as good as similar work obtained in previous experiments, which is sufficient to meet the requirements for manufacturing 2T0C DRAM units. Moreover, with the double-layer stacking of this structure , the feasibility and scalability of manufacturing DRAM units with CAA IGZO FET is verified.

Electrode design is critical for the performance and reliability of flip-chip AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs). We propose a semi-surround n-electrode design to achieve better current spreading for a relatively small DUV LED with a size of 8 × 15 mil². It is found that an optimal semi-surround n-electrode can reduce the operating voltage and increase the chip reliability due to the larger ohmic contact area. Moreover, the semi-surround n-electrode introduces multiple current injection paths, which causes the improvement of the current spreading in both the directions parallel (X) and perpendicular (Y) to the electrode fingers. However, an excessively long semi-surround n-electrode will decrease the light output power because of the severely reduced active region area. Furthermore, experiments and simulations reveal that the semi-surround n-electrode can improve the current spreading in theY-direction at high injection current. Meanwhile, it is also found that a short semi-surround n-electrode causes deteriorated current spreading in the X-direction due to the unbalanced resistance between n-electrode and p-electrode. Our work highlights the importance of two-dimensional current management in electrode design and provides a practical strategy for developing high-performance and reliable DUV LEDs with a relatively small chip size.

AlGaN-based ultraviolet (UV) laser diodes (LDs), with emission wavelength in the 280–365 nm range, are promising for applications in medical diagnostics and biological sensing, making them a prominent research focus in both academia and industry in recent years. A key challenge in their development is the large stress induced during the epitaxial growth of LD structures, which arises from the lack of lattice-matched substrates, and severely degrades the quantum efficiency and overall LD performance. This study presents an in-depth investigation into the growth mode and stress evolution of thick Al_0.2Ga_0.8N template. Firstly, we used the compressive stress between the Al_0.2Ga_0.8N layer and AlN/Sapphire substrate to form spontaneously three-dimensional growth to annihilate dislocations. Secondly, based on the Nakajima's theory of elasticity, we refined the conventional theoretical models for AlGaN strain relaxation of the S–K growth mode and critical thickness by considering the crucial role of threading dislocations (TDs) in releasing compressive stress. The experimentally measured critical thickness for three-dimensional growth was consistent with the calculated results. Furthermore, a crack-free high-quality 5 μm-thick Al_0.2Ga_0.8N template was successfully grown on an AlN/sapphire substrate.

This paper presents a reconfigurable eight-contact Hall device fabricated in the 180 nm BCD (Bipolar-CMOS-DMOS) process, providing a cost-effective solution for high-precision and wideband magnetic/current sensing. The device structural design supports two distinct operating modes: static biasing and spinning-current dynamic biasing. For wideband sensing, the static mode utilizes intrinsic orthogonal symmetry to achieve effective static offset cancellation. In contrast, the dynamic mode employs the spinning-current technique to achieve a remarkably low residual offset for high-precision low-frequency detection. To enhance the absolute sensitivity (S_A) and ensure electrical matching across both modalities, doping profiles and junction depths are meticulously optimized. Experimental results demonstrate that the device in static mode achieves a high S_A of 283 mV/T at 1200 μA, representing an 89% improvement over existing X-Hall devices, with an initial offset standard deviation (σ) of only 0.216 mV. In the dynamic mode, the device yields a matched S_A of 281 mV/T and a remarkably low residual offset of 27 μV. Notably, the input resistance remains highly consistent across both modalities (3.14 and 3.32 kΩ). This reconfigurable architecture provides a robust device-level foundation for wideband sensing in demanding power electronic applications.

Spin−orbit torque (SOT) is widely considered as the key technology for next-generation magnetic random-access memory (MRAM), leveraging ultrafast operating speed and unlimited endurance. However, integrating perpendicular magnetic anisotropy (PMA) SOT-MRAM stacks with the back-end-of-line (BEOL) thermal budget remains a critical challenge, as PMA degradation and Pt−Fe interdiffusion typically occur under 400 °C annealing. Here we propose a double CoFeB reference layer (DCFB) structure to address these issues. The additional CoFeB reference layer and two extra CoFeB/W interfaces significantly enhance the PMA of the reference layers, while improving the crystallization of the overlying Pt/Co multilayers. Furthermore, the DCFB stack effectively acts as a diffusion barrier against Pt−Fe interdiffusion. Consequently, a fabricated magnetic tunnel junction (MTJ) incorporating the DCFB stack achieves a high tunneling magnetoresistance (TMR) of 137% even after annealing at 400 °C. Our work provides a robust, simplified approach for the design of SOT-MRAM stacks with BEOL thermal budget tolerance.

A skipper image sensor (SIS) with lateral overflow gate-coupled capacitor (LOGCC) is proposed in this work. During the integration period, the transfer gates after TG are switched on to construct a LOGCC with specific operation timing. Once high light illumination fully charges the pinned photodiode (PPD), the extra photogenerated electrons will overflow to LOGCC, which effectively improve the dynamic range (DR) of SIS. Before the readout of signal in PPD, the electrons stored in LOGCC are sampled and then reset through the floating diffusion (FD). In the end, the electrons in PPD are sampled by the method of the conventional skipper pixels. According to TCAD simulation results, the extra electrons are transferred to LOGCC through the TG effectively. Measurement of prototype chip shows that the DR is extended to 89.3 dB. As contrast, the DR is 66 dB when switching off the transfer gates, i.e. LOGCC. Compared with traditional SIS, the proposed architecture achieved DR extension by introducing LOGCC which is constructed with transfer gates. Therefore, this study proposes the introduction of LOGCC to expand the application scenarios of SIS, providing a new approach for its use in conditions requiring stronger light.

The integration of two-dimensional (2D) semiconductors with mainstream complementary metal−oxide−semiconductor (CMOS) technology is hampered by the limited ability to adjust device performance after fabrication. Here, we present a differential Schottky-barrier tuning strategy to post-customize the optoelectronic performance based on a two-dimensional asymmetric Schottky contact WSe₂ photodiode, eliminating the need for device re-fabrication. A brief, room-temperature ozone exposure (1.5 min) enables in-situ tuning of the rectification ratio across three orders of magnitude (from 10² to 10⁵) and enhances the peak responsivity at 532 nm by 11.2 times. These effects stem from differential modulation of Schottky barrier height (SBH) at the asymmetric contacts. While the SBH at the WSe₂/Au interface is reduced, the SBH at the WSe₂/graphene junction is elevated, a phenomenon unlocked by the combination of oxidation-induced Fermi-level lowering in WSe₂ and interfacial dipole modification. Our method establishes a "device-after-design" paradigm for 2D material engineering, providing a CMOS-compatible and versatile route toward adaptive optoelectronics for applications in wearable sensing and reconfigurable photonic systems.

Achieving simultaneous phase stabilization and ultralow leakage remains a fundamental challenge for ZrO₂-based high-k dielectrics. This work demonstrates high-performance 5.7 nm ZrO₂-based metal-insulator-metal capacitors through coordinated interfacial engineering and defect passivation. The AlZrO alloy interfacial layer preserves lattice coherence and provides an interfacial barrier while stabilizing the anti-ferroelectric tetragonal phase ZrO₂, enabling an equivalent oxide thickness of 0.89 nm. Subsequent in-situ remote O₂ plasma treatment passivates oxygen vacancies via radical oxidation without inducing plasma damage. As a result, the capacitors achieve an ultralow leakage current density of 3×10⁻¹⁰ A/cm² at 1 V, a breakdown voltage exceeding 5 V, and a projected 10-year operating voltage above 2.4 V based on time-dependent dielectric breakdown extrapolation. All processes are conducted below 350 °C, ensuring back-end-of-line (BEOL) compatibility. These results demonstrate a pathway toward simultaneous dielectric constant enhancement, leakage suppression, and long-term reliability in ultrathin ZrO₂-based high-k dielectrics.