The p-type and n-type transistors are the basic components for building CMOS electronic devices for logic circuits. Most two-dimensional materials are n-type due to strong electron doping by intrinsic structural defects. Notably, the p-type conductivity of MoS2 is hardly achievable by the limited electric field modulation from the low dielectric constant of Si/SiO2. However, through strong dielectric screening of a high dielectric constant substrate and powerful polarization electric field of ferroelectric material, the p-type transition of MoS2 can be realized. In this paper, with the help of ferroelectric field modulation of high dielectric constant P(VDF-TrFE), a significant modulation of the band structure of MoS2 is realized, and finally, a flexible p-type modulation of MoS2 is obtained. The band changes and electrical properties of MoS2 on three different dielectric constant substrates, including Si/SiO2, hBN, and P(VDF-TrFE), were quantitatively studied with Kelvin probe force microscopy (KPFM). Fermi level changes and band n-p transitions of MoS2 under ferroelectric modulation were also systematically investigated by KPFM. The ferroelectric modulation of the MoS2 Fermi level can realize a wide range of flexible modulation up to nearly 900 meV. This work reveals the device physics of the realization of p-type transport from the band perspective and provides an effective and viable reference for p-type modulation of other two-dimensional materials. It also provides a boost for the application of MoS2 in high-performance electronic and optoelectronic devices.

Ferroelectric memory, with its promise of low power consumption, high writing speed and exceptional endurance, requires the scaling of ferroelectric films to ultrathin dimensions—often just a few atomic layers thick. However, such extreme thinning risks destabilizing or even erasing electric polarization, mainly due to the detrimental depolarization field. Remarkably, certain ferroelectrics exhibit an intrinsic immunity to this effect, as predicted theoretically and confirmed experimentally. Examples include improper ferroelectrics, hyper ferroelectrics, engineered heterostructures, and low-dimensional von der Waals ferroelectrics. This review systematically examines these unique materials, unravelling the fundamental physics behind their polarization robustness and the mechanisms enabling them to resist the depolarization field. By bridging theory with experimental advances, we aim to inspire the design of next-generation ferroelectrics capable of overcoming critical challenges encountered in practical ferroelectric memory devices.

Van der Waals (vdW) lamination, a low-energy physical stacking technique, holds great promise for two-dimensional (2D) electronics and future three-dimensional (3D) integration. However, achieving ultra-clean interfaces-free from interlayer molecular contaminants-remains a significant challenge. Here, we introduce an elastic bevel stamp-assisted thermal lamination (EBTL) technology, operated at 150 °C, which actively self-expels interlayer molecular impurities (e.g., water, oxygen), eliminating bubbles, wrinkles, and defects, yielding pristine vdW interfaces. Through nanomechanical analysis, we optimize key parameters of bevel stamp, such as angle and size, to ensure clean and damage-free lamination of 2D monolayer at large scales. This method enables reliable preparation of ultra-clean 2D stacked structures with an average interface yield >95%. Devices fabricated with it exhibit improved performance compared to conventional methods, as evidenced by hysteresis-free hBN top-gate transistors (∼10 mV) and ultrafast hetero-diodes (470 ns). The lamination of wafer-scale monolayers, twisted bilayers, and complex superlattices can be readily achieved with clean interfaces. It is also applicable to clean lamination of various building blocks, such as 2D channels, 3D metals, and dielectrics. We therefore demonstrate a fully vdW-laminated 2D transistor array (2400 transistors on a 0.25 cm2 area), where all components are stacked along the z-direction, achieving low device-to-device variability. Our work provides a promising approach for clean vdW integration and high-performance vdW electronics.

Miniaturized spectrometers are crucial for advancing compact, energy-efficient, and real-time spectral sensing systems. However, traditional spectrometer architectures are limited by mechanical components and efficiency, making it difficult to consistently shrink their size. Here, we report a miniaturized computational spectral sensing platform based on a ferroelectrically reconfigurable WSe2 homojunction, achieving both high-resolution spectral reconstruction and dynamic spectral sensing. The device operates under a non-volatile, near-zero-power standby mode enabled by the retention property of ferroelectric polarization, ensuring energy-efficient monitoring without a continuous power supply. Event-driven triggers combined with computational reconstruction enable real-time spectral tracking with ∼32 µs response latency. This system shows broad spectral sensitivity (450 nm-950 nm) and the capability to detect dynamic spectral variations, validated via monitoring reflectance spectra of VO2 film during phase transitions. This work reveals great potential for low-power, real-time spectral sensing, paving the way for on-site spectral analysis.

Two-dimensional (2D) semiconductors are promising candidates for continued complementary metal-oxide semiconductor (CMOS) scaling, yet scalable p-type contacts still lag behind despite substantial progress in n-type contact engineering (e.g., semimetals). Here, we present a semiconductor-semiconductor van der Waals (S-S vdW) contact strategy in which the low density of states and low-energy deposition of SnS effectively suppress metal-induced gap states and defect-induced gap states. As a result, SnS contacts exhibit minimal Fermi-level pinning and enable a negligible hole-injection barrier, which is unattainable using conventional high-work-function metals such as Pd or Pt. Furthermore, SnS-WSe2 transistors demonstrate a high on-off ratio of >1010, a contact resistance as low as 395 Ω μm, and an on-state current density of up to 1.11 mA μm-1 at VDS = -2 V with a 60 nm channel length. This work provides a practical and reliable pathway toward high-performance 2D p-FETs and scalable 2D CMOS integration.

Near-infrared and short-wave infrared dual-band detection has emerged as a pivotal enabling technology in across diverse applications spanning material identification, biological diagnostics, and machine vision. Current dual-band device architectures based on vertically stacked photodetectors such as those employing two-dimensional materials or back-illuminated colloidal quantum dots remain constrained by limited large-area manufacturability and incompatibility with standard readout integrated circuits. Here, we report a top-illuminated p-i-n-i-p dual-band photodetector using two distinct sizes of solution-processed PbS colloidal quantum dots, which enables bias-switchable spectral response between near-infrared and short-wave infrared regimes. The device achieves a specific detectivity exceeding 1×1011 cm·Hz1/2·W-1 in both bands, with short-wave infrared crosstalk of 0.5% and near-infrared crosstalk of 7.7%. The successful fabrication of a monolithic integrated 128×128 dual-band focal plane array showcases a functional dual-band infrared imager. This work establishes a scalable and silicon-compatible platform toward high-performance, low-cost dual-band infrared imagers.

Pyroelectric detectors are widely employed as uncooled infrared sensors. However, their conventional capacitorbased design generates weak electrical signals, requiring complex external amplification that limits integration density and signal-to-noise ratio. Here, we design and fabricate suspended pyroelectric-ferroelectric field-effect transistors (Pyro-FeFETs) featuring a monocrystalline lithium tantalate (LiTaO3) gate dielectric and a graphene channel. Infrared-induced temperature variations alter the ferroelectric spontaneous polarization in LiTaO3 due to perturbation of its internal dipole alignment. This ferroelectric polarization change effectively modulates the carrier concentration and conductivity of the graphene channel, resulting in a measurable current signal through the source-drain electrodes. Leveraging inherent nonlinear signal amplification of field-effect transistors and a suspended micro-bridge for enhanced thermal isolation, the device achieves uncooled blackbody infrared detection with a specific detectivity of 1.4 & times; 109 cm Hz1/2 W- 1 and a response time of 51/38 ms. This integrated sensing-amplification architecture establishes a promising architecture for highly sensitive and compact uncooled infrared systems.

Spectrometers that operate without dispersive optics or filter arrays offer a compact route toward integrated mid-infrared sensing. However, a key challenge is to effectively encode and decode wavelength information within a single detector. Here, we demonstrate a bias-tunable spectrometer based on composition-graded Hg1−xCdxTe (HgCdTe), in which a continuous bandgap gradient enables electrically controlled spectral selectivity over the 2–3 µm range. A planar n-on-p junction is embedded within the graded absorber, allowing the depletion region to extend into narrower-bandgap regions under applied bias, resulting in a systematic red-shift of the spectral response. Spectral information encoded in the bias-dependent current-voltage (I-V) characteristics is decoded using an implicit response matrix learning (IRML) framework. A supervised neural network directly learns the nonlinear mapping from I-V curves to incident spectra without explicit response matrix calibration. Accurate reconstruction is achieved for broadened monochromatic inputs, densely sampled sequential narrowband inputs, and experimentally measured spectra. A mid-wave infrared imaging proof-of-concept further visualizes bias-dependent spectral contrast via differential imaging. Together, these results demonstrate a compact and electrically tunable HgCdTe spectrometer architecture compatible with scalable HgCdTe detector technology.

To achieve the detection of extremely weak signals from pyroelectric infrared detectors and to meet the demands of high-sensitivity applications, this paper proposes a dual-capacitor transimpedance amplifier (CTIA) readout structure featuring a variable array size. Additionally, a bandgap reference and a low dropout regulator (LDO) are designed as the bias circuit to provide voltage bias, in order to meet the requirements of low noise, low power consumption, large dynamic range and portability. The circuit is designed in TSMC 0. 18 mu m 1P6M CMOS process under a 3. 3V supply. For the layout implementation, advanced techniques, including dummy structures and guard rings, are employed to improve device matching, overall layout symmetry, as well as the noise immunity and electrical stability of the analog circuitry.

Metal contacts remain one of the key bottlenecks in two-dimensional (2D) semiconductor electronics. We developed an atomic-scale step-by-step evaporation method to directly grow single-crystal metals on monolayer semiconductors with clean interfaces. This method accesses a distinct growth-kinetic window that suppresses secondary nucleation and promotes lateral coalescence, enabling van der Waals epitaxy of diverse metals-including bismuth, silver, indium, gold, and palladium-on molybdenum disulfide (MoS2) and tungsten diselenide (WSe2). The single-crystal metals support ultrathin conduction, provide spatially uniform work functions, and exhibit improved thermal robustness. As contacts, they show minimal Fermi-level pinning, approaching the Schottky-Mott limit. With bismuth and palladium contacts, monolayer MoS2 and WSe2 transistors achieved ultralow n- and p-type contact resistances of 36 and 145 ohm-micrometers, respectively, and short-channel currents both above 1.1 milliampere per micrometer.

In-memory computing is pursued to overcome the memory and power walls inherent to the von Neumann architecture. However, heterosynaptic memtransistors with higher modulation dimensionality and enhanced memory capability still suffer from a limited conductance dynamic range and few gate-controlled states, constraining learning precision. Here, an all-ferroelectric memtransistor is demonstrated that synergistically combines a P(VDF-TrFE) ferroelectric gate dielectric with an alpha-In2Se3 ferroelectric semiconductor channel. As the third-terminal modulator, the P(VDF-TrFE) gate sets the channel Fermi level via out-of-plane polarization reversal, while the channel's in-plane polarization at the pre- and post-synaptic drain and source asymmetrically tunes the contact Schottky barriers. The coupling of these two distinct ferroelectric effects generates four well-separated nonvolatile conductance states in fully polarized configurations, introduces 12 third-terminal states via ferroelectric-gate domain control, and enables 100 intermediate states in the ferroelectric channel through source-drain pulses. The device emulates heterosynaptic regulation, enabling global enhancement or suppression of synaptic features. Compared with conventional designs, it offers a dynamic range of up to 331.91 and 12 gate-controlled states. An adaptive neural network implemented with measured device characteristics achieves 95.68% pattern recognition accuracy, with gate pulses selecting optimal operational regimes. This work provides an effective device platform for high-performance brain-inspired computing.

High-operating-temperature (HOT) mid-wavelength and long-wavelength infrared photodetectors have emerged as critical enablers for eliminating bulky cryogenic cooling systems, offering transfromative potential in developing compact, energy-efficient infrared technologies with reduced size, weight, power, and cost. Focusing on infrared photodiodes, this review first discusses the fundamental mechanisms limiting performance at elevated operating temperatures. Subsequently, the progress in conventional epitaxial semiconductors, such as HgCdTe, InAsSb, and III-V type-II superlattice is reviewed, highlighting the evolution of device architectures designed to effectively suppress dark currents and approach background-limited performance. The review then surveys recent advancements in emerging material systems for HOT infrared photodiodes, including colloidal quantum dots, 2D materials, and amorphous or polycrystalline thin films. Finally, a comparative analysis of the high-temperature performance of devices from both conventional and emerging material systems is presented to enable benchmarked evaluation, followed by an outlook on future research directions.

In the era of big data and artificial intelligence, the rising demand for data-intensive processing, alongside the need to minimize system complexity, underscores the growing importance of non-volatile memory with electro-optic capabilities. Against this backdrop, significant exploration of advanced memory architectures has been spurred. Here, we present a ferroelectric semiconductor ferroelectric field-effect transistor (FeS-FeFET) whose channel and gate dielectric are both ferroelectric materials. It establishes a dual-mode, multi-state non-volatile optoelectronic memory. Through investigation of in-plane polarization in the ferroelectric channel and out-of-plane polarization in the ferroelectric gate dielectric, the device demonstrates two-level electrical programming and erasing, along with robust optoelectronic memory characteristics. Specifically, the device exhibits four distinct resistance states under a 5 V operating voltage, with programming speeds up to 40 ns, an optical memory capacity of 7 bits, a maximum on/off current ratio of 104, and a retention time exceeding 103 s. This work presents promising advancements for future high-density, low-power technologies, with broad applications in high-density data memory and neuromorphic computing.

Semiconductor heterostructures play a crucial role in optoelectronics. The interface mismatch of heterogeneous materials leads to nonideal carrier transport. In infrared detectors, the interface mismatch results in a high dark current, which leads to low sensitivity, operating temperature, and large size. Here, van der Waals (vdWs) heterogeneous integration is introduced into mercury cadmium telluride (MCT)‐based infrared detectors. Two types of vdWs barrier structure MCT‐based devices are demonstrated, including a graphene/SnS 2 /HgCdTe vdWs device and a graphene/MoSe 2 /HgCdTe vdWs device, to achieve high‐operating‐temperature (HOT) mid‐wave infrared detection. Thanks to vdWs integration, unipolar barrier structures with high‐quality interfaces are achieved, showing effective suppression of dark current at high temperatures. The dark current density of the MCT‐based vdWs detector is ≈10 −2 A cm −2 at room temperature. The MCT‐based vdWs barrier detectors have great potential for uncooled infrared detection. The detectors show a sensitive response to mid‐wave infrared irradiation with a high detectivity of 3.01 × 10 10 cm Hz 1/2 W −1 and a high external quantum efficiency of 60.9% at room temperature. The findings present a versatile strategy for fabricating a superior interface for high‐operating‐temperature infrared photodetectors with high sensitivity and small size. It makes a significant step forward in the development route of photodetectors.

The pursuit of suitable insulating layers and high-quality integration methods is important to further improve the performance of field-effect transistors (FETs). In this study, we employ transferable high-k oxide films as device gate dielectrics to fabricate high-quality optoelectronic devices by optimizing the interface between the dielectric material and the two-dimensional (2D) materials. Through meticulous refinement, a transferred film roughness of 269.27 pm was achieved, resulting in intact, crack-free SrTiO3 films. The molybdenum disulfide (MoS2) transistors exhibited remarkable characteristics, including a high on/off ratio (ION/IOFF) of 1 × 108, a subthreshold swing as low as 69.2 mV/dec, and a field-effect mobility reaching 230 cm2/(V·s). Additionally, the SrTiO3 films were combined with molybdenum telluride (MoTe2) to fabricate PN junctions capable of functioning as photodetectors at extremely low operating voltages (±2 V). The exceptional performance of both the MoS2 FETs and the MoTe2 PN junctions can be attributed to the optimized, high-quality dielectric/semiconductor heterojunction interface. This further demonstrates the versatility of the van der Waals integration method employed in this research.

Perovskite oxide-based heterostructures exhibit a range of exotic physical properties such as two-dimensional superconductivity, interface magnetism, tunable Kondo effect, and tunable spin-orbit coupling. Here, the magnetotransport properties of Al2O3/SrTiO3 and Al2O3/KTaO3 heterostructures are studied. Both Kondo effect and spin-orbit coupling-induced weak antilocalization (WAL) effect are observed at low temperatures. By analyzing the WAL curves, the spin relaxation time is extracted. Surprisingly, the extracted spin relaxation time unexpectedly decreases on increasing temperature in all samples. This indicates that the strength of the spin-orbit coupling is progressively enhanced on increasing temperature, conflicting with theoretical prediction. This anomalous temperature dependence is explained by the interplay between the Kondo effect and the D’yakonov-Perel spin relaxation mechanism.

In the realm of optoelectronics, photodetectors play pivotal roles, with applications spanning from high-speed data communication to precise environmental sensing. Despite the advancements, conventional photodetectors grapple with challenges with response speed and dark current. In this study, we present a photodetector based on a lateral MoTe2 p-n junction, defined by a semi-floating ferroelectric gate. The strong ferroelectric fields and the depletion region of the p-n junction in the device are notably compact, which diminish the carrier transit time, thereby enhancing the speed of the photoelectric response. The non-volatile MoTe2 homojunction, under the influence of external gate voltage pulses, can alter the orientation of the intrinsic electric field within the junction. As a photovoltaic detector, it achieves an ultra-low dark current of 20 pA, and a fast photo response of 2 mu s. The spectral response is extended to the shortwave infrared range at 1550 nm. Furthermore, a logic comput & hybull;ing system with light/no light as binary input is designed to convert the current signal to the voltage output. This research not only underscores the versatility of 2D materials in the realm of sophisticated photodetector design but also heralds new avenues for their application in energy-efficient, high-performance optoelectronic devices

The human eye is highly advanced but limited by color blindness and poor adaptation to changing light. Artificial photodetectors attempt to mimic vision but often require complex processing to overcome these limitations. Thus, developing photodetectors that complement human vision is crucial to overcoming these limitations. Here, we report a CuInP2S6-based photodetector array with tunable photoresponse for in-sensor image processing, directly complementing human vision. Through ionic and electronic tuning, the photodetector shows both positive and negative correlations with light intensity and wavelength. It enhances signal-to-background ratio by 880% and suppresses noise by 1,170 times, allowing effective detection of weak signals under strong illumination. Moreover, taking advantage of the distinct photoresponse to red and green light, the photodetector could improve the contrast between red and green patterns up to 43%, offering potential aid for red-green color blindness. This work presents a vision-enhancing photodetector capable of compensating for human visual deficiencies without external computation.

Perovskite oxide-based heterostructures exhibit a range of exotic physical properties such as two-dimensional superconductivity, interface magnetism, tunable Kondo effect, and tunable spin-orbit coupling. Here, the magnetotransport properties of Al2O3/SrTiO3and Al2O3/KTaO3heterostructures are studied. Both Kondo effect and spin-orbit coupling-induced weak antilocalization (WAL) effect are observed at low temperatures. By analyzing the WAL curves, the spin relaxation time is extracted. Surprisingly, the extracted spin relaxation time unexpectedly decreases on increasing temperature in all samples. This indicates that the strength of the spin-orbit coupling is progressively enhanced on increasing temperature, conflicting with theoretical prediction. This anomalous temperature dependence is explained by the interplay between the Kondo effect and the D'yakonov-Perel spin relaxation mechanism.

Hg1-xCdxTe (MCT) is a critical material for infrared detectors. The foundation of developing ultra-high-performance detectors lies in the suppression of defects in MCT films. In this study, MCT thin films were grown on CdZnTe substrates using molecular beam epitaxy. The formation mechanism and mitigation strategies of needle-like defects-macroscopic surface defects-were systematically investigated. By controlling the growth temperature, it was found that the occurrence of these needle-like defects is associated with a temperature rise on the surface during the later stages of growth. This phenomenon is attributed to stress propagation induced by the formation of internal voids within the material. High-resolution transmission electron microscopy combined with geometric phase analysis was employed to elucidate the atomic structure and strain distribution of the needle-like defects. Through the optimization of the growth process, the formation of such defects on the MCT surface was effectively suppressed. As a result, the full width at half maximum of the x-ray double-crystal rocking curve was reduced to only 41.8 arc sec, indicating a significant improvement in crystalline quality. This work provides essential theoretical insights and practical guidance for defect control and further process optimization in high-performance MCT infrared detectors.