J. L. Wang

Chinese Academy of Sciences | CAS · National Laboratory for Infrared Physics

Photodetectors are essential optoelectronic devices that play a critical role in modern technology by converting optical signals into electrical signals, which are one of the most important sensors of the informational devices in current ‘Internet of Things’ era. Two-dimensional (2D) material-based photodetectors have excellent performance, simple...

Mix‐dimensional heterojunctions (MDHJs) photodetectors (PDs) built from bulk and 2D materials are the research focus to develop hetero‐integrated and multifunctional optoelectronic sensor systems. However, it is still an open issue for achieving multiple effects synergistic characteristics to boost sensitivity and enrich the prospect in artificial...

This work is devoted to the study of nanosized polymer polyvinylidene fluoride (PVDF) thin ferroelectric films (two-dimensional ferroelectrics) and their composites with graphene layers, using molecular dynamics methods to (1) study and calculate the polarization switching time depending on the electric field and film thickness, (2) study and calcu...

III–V Indium Arsenide (InAs) nanowire photodetectors have attracted intensive research attention due to their high carrier mobility, direct and narrow bandgap, and nanoscale dimensions, offering immense potential in nanoscale optoelectronics, particularly for applications in photonic integrated circuits. Despite extensive studies on the properties...

The barrier structure is designed to enhance the operating temperature of the infrared detector, thereby improving the efficiency of collecting photogenerated carriers and reducing dark current generation, without suppressing the photocurrent. However, the development of barrier detectors using conventional materials is limited due to the strict re...

This work is devoted to consideration and analysis of the application of molecular dynamics simulation (MDS) methods to the study of nanosized polymer polyvinylidene fluoride (PVDF) thin ferroelectric films (two-dimensional ferroelectrics) and their composites with graphene layers: 1) to study and calculations of the polarization switching time dep...

Hafnia-based films are gaining prominence in the advancement of next-generation memory and logic devices. Their significance arises from their pronounced ferroelectricity at the nanoscale and their synergy with silicon processes. However, there are questions surrounding how their polarization stability responds to changes in temperature. In our stu...

The utilization of hot carriers as a means to surpass the Shockley‐Queasier limit represents a promising strategy for advancing highly efficient photovoltaic devices. Quantum dots, owing to their discrete energy states and limited multi‐phonon cooling process, are regarded as one of the most promising materials. However, in practical implementation...

Integrated multifunctionality in visual information processing is crucial in the artificial intelligence era. Compared to the parallel human vision system, current bionic vision devices exhibit a complex structure with single functionality, challenging intelligent processing and integration. Here, a multisensory artificial synapse with a crossbar s...

Among today’s nonvolatile memories, ferroelectric-based capacitors, tunnel junctions and field-effect transistors (FET) are already industrially integrated and/or intensively investigated to improve their performances. Concurrently, because of the tremendous development of artificial intelligence and big-data issues, there is an urgent need to real...

The realization of a controllable transparent conducting system with selective light transparency is crucial for exploring many of the most intriguing effects in top‐illuminated optoelectronic devices. However, the performance is limited by insufficient electrical conductivity, low work function, and vulnerable interface of traditional transparent...

With the continuous advancement of nano‐fabrication techniques, development of novel materials, and discovery of useful manipulation mechanisms in high‐performance applications, especially photodetectors, the morphology of junction devices and the way junction devices are used have been fundamentally revolutionised. Simultaneously, new types of pho...

Tunneling devices hold significant potential for integrated circuit and microelectronic devices field, but conventional bulk semiconductors like silicon and gallium arsenide are reaching their limits in terms of scaling down and efficient gate regulation. However, the emergence of 2-D materials, which consist of atomically thin layers, offers highl...

Recently, the increasing demand for data-centric applications is driving the elimination of image sensing, memory and computing unit interface, thus promising for latency- and energy-strict applications. Although dedicated electronic hardware has inspired the development of in-memory computing and in-sensor computing, folding the entire signal chai...

2D materials are considered as potential candidates for the next generation of optoelectronic materials. However, their optical absorption is typically weak due to thickness limitations, greatly restricting the photodetection capabilities of devices. To enhance the photoelectric gain of 2D materials or devices and improve detection sensitivity, var...

The acquisition of multi-dimensional optical information, including light intensity, spectrum, polarization, and phase, is a crucial aspect in the advancement of next-generation infrared photodetectors. However, the acquisition of multi-dimensional optical information on a single photodetector presents a significant challenge. Here, we present a mu...

As a narrow‐bandgap semiconductor, InSb is widely used in infrared (IR) detection due to its excellent performance and other characteristics such as ultrahigh electron mobility, extremely high quantum efficiency, and robust chemical properties. Herein, an ultralow dark current room‐temperature IR photodetector based on InSb nanosheets (NSs)/MoS 2 f...

Laterally epitaxial two‐dimensional (2D) transition metal dichalcogenides (TMDs) heterojunctions are of considerable interest in recent years due to atomically sharp interfaces and tunable band alignment, which have potential applications in novel functional electronics and optoelectronics. However, the studies of 2D lateral heterostructures have m...

The very long wave infrared (VLWIR) is an electromagnetic wave with a wavelength range of 15-30 μm, which plays an important role in missile defense and weather monitoring. This paper briefly introduces the development of intraband absorption of colloidal quantum dots (CQDs) and investigates the possibility of using CQDs to produce VLWIR detectors....

The two-dimensional layered material CuInP2S6 (CIPS) has attracted significant research attention due to its nontrivial physical properties, including room-temperature ferroelectricity at the ultrathin limit and substantial ionic conductivity. Despite many efforts to control its ionic conductance and develop electronic devices, such as memristors,...

Abstract Analog storage through synaptic weights using conductance in resistive neuromorphic systems and devices inevitably generates harmful heat dissipation. This thermal issue not only limits the energy efficiency but also hampers the very‐large‐scale and highly complicated hardware integration as in the human brain. Here we demonstrate that the...

Two-dimensional GaGeTe flakes with different thicknesses from 80 to 2.2 nm (bilayer) were exfoliated and transferred to a SiO 2 /Si substrate. A series of samples with different thicknesses were prepared and identified by optical microscopy, atomic force microscopy, and Raman spectrum. Raman modes strongly dependent on the layer thickness and chara...

Single-crystalline γ-MnTe thin films with zinc-blende structure were grown epitaxially on InP(111) by molecular beam epitaxy. Two-dimensional growth regime and atomic surface flatness are achieved, and appearance of Laue’s oscillation peaks illustrates the superior crystalline quality and interface of γ-MnTe films. A pseudocrystal buffer layer is f...

The Su-Schrieffer-Heeger (SSH) model can demonstrate the topological phase transition of spinless fermions in a two-dimensional square lattice. In this work, we investigate the topologically protected edge states (TESs) in 1D SSH ribbons by using the wave mechanics approach. A concise analytic equation is derived to determine the localization lengt...

Organic-inorganic hybrid semiconducting (OIHS) materials, which can detect broader spectral regions, are highly desired in several applications including biomedical imaging, night vision, and optical communications. Although lead (Pb)-halide perovskites have reached a mature research stage, high toxicity of Pb hinders their large-scale viability. T...

With the further miniaturization and integration of multi-dimensional optical information detection devices, polarization-sensitive photodetectors based on anisotropic low-dimension materials have attractive potential applications. However, the performance of these devices is restricted by intrinsic property of materials leading to a small polariza...

Ultralow‐Power Machine Vision In article number 2106092, Bobo Tian, Hui Peng, Chungang Duan, and co‐workers demonstrate that photovoltaic sensors can be used for in‐sensor reservoir computing (RC). Brain‐inspired vision is achieved by in‐sensor RC based on self‐powered Cs2AgBiBr6 photontic devices. Both image processing and dynamic video analysis a...

New-generation infrared detectors call for higher operation temperature and polarization sensitivity. For traditional HgCdTe infrared detectors, the additional polarization optics and cryogenic cooling are necessary to achieve high-performance infrared polarization detection, while they can complicate this system and limit the integration. Here, a...

Hafnium-oxide-based materials are considered a promising candidate for next-generation nonvolatile memory devices owing to their good CMOS compatibility and robust ferroelectricity at the nanoscale. In this work, we synthesize highly (111)-oriented La-doped HfO 2 (HLO) ferroelectric thin films via pulsed laser deposition. Furthermore, the effect of...

A neuromorphic visual system integrating optoelectronic synapses to perform the in‐sensor computing is triggering a revolution due to the reduction of latency and energy consumption. Here it is demonstrated that the dwell time of photon‐generated carriers in the space‐charge region can be effectively extended by embedding a potential well on the sh...

WS2 is a promising material in the next generation integrated circuit applications and its electrical and optoelectronic characteristics is dependent on the number of layers. Here, a simple and scalable synthesis of WS2 bilayers via chemical vapor deposition (CVD) is demonstrated by finely controlling the time of introducing sulfur. The optical and...

Flexible optoelectronic devices have numerous applications in personal wearable devices, bionic detectors, and other systems. There is an urgent need for functional materials with appealing electrical and optoelectronic properties, stretchable electrodes with outstanding mechanical flexibility, and gate medium with flexibility and low power consump...

CdTe, widely used in radiation detectors, optoelectronics and photovoltaics, is a typical II-VI semiconductor with covalent and ionic bonds where various defects are easily induced and their physics are well...

Flash memory has become a ubiquitous solid-state memory device widely used in portable digital devices, computers and enterprise applications. The development of the information age has demanded improvements in memory speed and retention performance. Here we demonstrate an ultrafast non-volatile flash memory based on MoS2/hBN/multilayer graphene va...

Infrared (IR) photodetection is important for light communications, military, agriculture, and related fields. Organic transistors are investigated as photodetectors. However, due to their large band gap, most organic transistors can only respond to ultraviolet and visible light. Here high performance IR phototransistors with ternary semiconductors...

Van der Waals integration with abundant two-dimensional materials provides a broad basis for assembling functional devices. In a specific van der Waals heterojunction, the band alignment engineering is crucial and feasible to realize high performance and multifunctionality. Here, we design a ferroelectric-tuned van der Waals heterojunction device s...

A single biological neuron can efficiently perform Boolean operations. Artificial neuromorphic systems, on the other hand, typically require several devices to complete a single operation. Here, we show that neuristors that exploit the intrinsic polarity of two-dimensional materials can perform logic operations in a single device. XNOR gates can be...

Photodetectors built from conventional bulk materials such as silicon, III–V or II–VI compound semiconductors are one of the most ubiquitous types of technology in use today. The past decade has witnessed a dramatic increase in interest in emerging photodetectors based on perovskite materials driven by the growing demands for uncooled, low‐cost, li...

Light polarization could provide critical visual information (e.g., surface roughness, geometry, or orientation) of the imaged objects beyond prevailing signals of intensity and wavelength. The polarization imaging technology thus has a large potential in broad fields such as object detection. However, intricate polarization coding is often require...

Unipolar barrier structures are used to suppress dark current in photodetectors by blocking majority carriers. Designing unipolar barriers with conventional materials is challenging due to the strict requirements of lattice and band matching. Two-dimensional materials have self-passivated surfaces and tunable band structures, and can thus be used t...

Two-dimensional (2D) layered materials have received significant attention owing to their unique crystal structures as well as outstanding optical and electric properties in photoelectric detection. However, most 2D materials are very sensitive to the environment. Adsorbates and traps introduced during the preparation process have a negative effect...

Blackbody-sensitive room-temperature infrared detection is a notable development direction for future low-dimensional infrared photodetectors. However, because of the limitations of responsivity and spectral response range for low-dimensional narrow bandgap semiconductors, few low-dimensional infrared photodetectors exhibit blackbody sensitivity. H...

The dangling‐bond‐free surfaces of 2D materials enable them to possess various degrees of freedom to form heterostructures with non‐2D materials. This allows for the combination of the advantages of different dimensional materials to fabricate van der Waals (vdW) heterostructures, thereby improving device performance and even bringing diversity and...

Brain‐inspired associative memory is meaningful for pattern recognitions and image/speech processing. Here, a ferroelectric synaptic transistor network is proposed that is capable of associative learning and one‐step recalling of a whole set of data from only partial information. The competition between an external field and the internal depolariza...

In this work, we show electrical polarization of ferroelectric P (VDF-TrFE) polymer can be used to engineer the photoluminescence (PL) at bilayer WSe2. The total PL intensity substantially is suppressed under negative polarization and enhanced in positive polarization with increasing the polarization intensity of P (VDF-TrFE) polymer. And the elect...

The development of novel low-dimensional materials makes the metallic contact to nanostructure facing challenges. Compared to side contacts, end-bonded contacts are proposed to be more effective pathways for charge injection and extraction. However, there is a lack of up-to-date understanding regarding end-bonded contacts, especially the recently e...

Van der Waals (vdW) integration with abundant two-dimensional materials provides a broad basis for assembling functional devices. However, band alignment in a specific vdW heterojunction (VHJ) is difficult to tune, restricting its multifunctionality and structural simplicity. Here, we designed a ferroelectric-tuned VHJ (Fe-VHJ) device structure by...

Polarized photodetectors with wide spectral detection and ultra-fast photo-responses based on anisotropic semiconductors have potential applications in military and civilian fields and have been widely studied in recent years. The dual advantages of low-symmetry crystal structure and special electronic band-structure make Sb 2 S 3 the perfect choic...

2D transition metal dichalcogenides (TMDs) are promising semiconductive films for applications in future devices due to their prosperous and tunable band structures. However, most TMD‐based top gate transistors suffer from a significant doping effect in the channel due to the subsequent deposition high‐k dielectric layer and metal gate, which limit...

Indium antimony is a direct, narrow bandgap III–V semiconductor with ultrahigh carrier mobility and an attractive optoelectronic device candidate for use in the visible to infrared region. Here, an infrared (IR) photodetector based on high‐quality InSb nanosheets (NSs) is presented, which shows a clear photoresponse over a broad spectral range from...

The polarization switching kinetics of nanosized ferroelectric crystals and the transition between homogeneous and domain switching in nanoscale ferroelectric films are considered. Homogeneous switching according to the Ginzburg-Landau-Devonshire (LGD) theory is possible only in two-dimensional (2D) ferroelectrics. The main condition for the applic...

The advent of low-dimensional materials with peculiar structure and superb band properties provides a new canonical form for the development of photodetectors. However, the limited exploitation of basic properties makes it difficult for devices to stand out. Here, we demonstrate a hybrid heterostructure with ultrathin vanadium dioxide film and moly...

Hysteresis-free and low-voltage operation are essential for low-power-consumption electronics. Herein, MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> transistors configured with bilayer-stacked polymethyl methacrylate (PMMA)/poly (vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) gate d...

The ultrabroadband spectrum detection from ultraviolet (UV) to long‐wavelength infrared (LWIR) is promising for diversified optoelectronic applications of imaging, sensing, and communication. However, the current LWIR‐detecting devices suffer from low photoresponsivity, high cost, and cryogenic environment. Herein, a high‐performance ultrabroadband...

Temperature-dependent dielectric spectroscopy was used to observe multiple dielectric responses involving four sets of dielectric relaxations (DRs) in molecular beam epitaxy-deposited ultrathin (001) SrMnO3/Nb:SrTiO3 heterojunctions. Two sets of oxygen-vacancy (OV)-related DRs, which were sensitive to oxygen annealing, were attributed to short-rang...

MoS2, one of the most valued 2D materials beyond graphene, shows potential for future applications in postsilicon digital electronics and optoelectronics. However, achieving hole transport in MoS2, which is dominated by electron transport, is always a challenge. Here, MoS2 transistors gated by electrolyte gel exhibit the characteristics of hole and...

Doped p-n junctions are fundamental electrical components in modern electronics and optoelectronics. Due to the development of device miniaturization, the emergence of two-dimensional (2D) materials may initiate the next technological leap toward the post-Moore era owing to their unique structures and physical properties. The purpose of fabricating...

Recently, a large amount of effort has been devoted to bringing p- and n-type two-dimensional (2D) materials in close contact to promise a p–n junction for photodetectors and photovoltaic devices. However, all solar cells based on 2D materials are single p–n junctions so far, where the open circuit voltage is usually limited by the bandgap of semic...

Semiconductor devices based on two-dimensional (2D) transition metal dichalcogenides could help overcome the scaling limits of silicon complementary metal–oxide–semiconductor (CMOS) technology. However, the development of atomically thin devices requires approaches to control the carrier type in 2D semiconductors. Here, we show that a scanning prob...

Gallium oxide (Ga2O3) has been studied as one of the most promising wide bandgap semiconductors during the past decade. Here, we prepared high quality β-Ga2O3 films by pulsed laser deposition. β-Ga2O3 films of different thicknesses were achieved and their crystal properties were comprehensively studied. As thickness increases, grain size and surfac...

Toward pursuing high‐performance photodetectors based on 2D transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2), it is desirable to reduce the high dark current and sluggish response time. Here, in multilayer MoS2‐based photodetectors, a 2D halide perovskite, (C6H5C2H4NH3)2PbI4 ((PEA)2PbI4), is introduced as a bifunctional m...

Cavity polaritons, originating from the strong coupling effect between cavity modes and excitons, have been tremendously investigated because of their high potential in new or quantum optoelectronic devices. Among them, realization of their dynamic controllability is highly desirable for real applications. In this work, we present a dynamic modulat...

Sensitive photodetection is crucial for modern optoelectronic technology. Two-dimensional molybdenum disulfide (MoS2) with unique crystal structure, and extraordinary electrical and optical properties is a promising candidate for ultrasensitive photodetection. Previously reported methods to improve the performance of MoS2 photodetectors have focuse...

Two-dimensional (2D) transition metal dichalcogenides (TMDs) based photodetectors have shown great potential for the next generation optoelectronics. However, most of the reported MoS2 photodetectors function under the photogating effect originated from the charge-trap mechanism, which is difficult for quantitative control. Such devices generally s...

Molybdenum disulfide (MoS2) holds great promise in the future applications of nanoelectronics and optoelectronic devices. Exploring those interesting physical properties of MoS2 using a strong electric field provided by electrolyte-gel is a robust approach. Here, we fabricate an MoS2 phototransistor gated by electrolyte-gel which is located on a fu...

Great attention has been paid to organic–inorganic hybrids in searching single-phase multiferroics because of their flexible structure design. Here, a new [CuCl4]2- based organic–inorganic hybrid, (bix)CuCl4·H2O (bix = 1,4-bis(imidazol-1-ylmethyl)benzene), is synthesized via simple solution method. Different from most [CuCl4]2- based organic–inorga...

2D transition metal dichalcogenides (TMDs) based photodetectors have shown great potential for the next generation optoelectronics. However, most of the reported MoS2 photodetectors function under the photogating effect originated from the charge‐trap mechanism, which is difficult for quantitative control. Such devices generally suffer from a poor...

A HfO2-based thin film is a nanoscale ferroelectric material with a high-k dielectric and CMOS compatibility, which make it a promising candidate for high-performance electronics. Here, we demonstrate the synthesis of a ferroelectric Y-doped HfO2 (HYO) thin film by pulsed laser deposition. This HYO thin film is gradient doped by alternately deposit...

A Schottky barrier is a double-edged sword in electronic and optoelectronic devices, especially devices based on 2D materials. It may restrict the carrier transport in devices, but it can also realize multi-functional devices by architecture design. We designed a simple but novel device structure based on WSe2-Cr Schottky junction with asymmetric S...

Photogating detectors based on 2D materials attract significant research interests. However, most of these photodetectors are only sensitive to the incident intensities and lack the ability to distinguish different wavelengths. Color imaging based on these detectors usually requires additional optical filter arrays to collect red, green, and blue (...

During the past decades, transition metal dichalcogenides (TMDs) have received special focus for their unique properties in photoelectric detection. As one important member of TMDs, MoS 2 has been made into photodetector purely or combined with other materials, such as graphene, ionic liquid, and ferroelectric materials. Here, we report a gate-free...

In article number 1901050, Jianlu Wang, Weida Hu, and co‐workers develop a type of photodetector with ultrabroad spectrum response from 375 nm to 10 µm. With the synergism of multi‐mechanisms in atomic‐layered semiconductor and quasi‐freestanding organic ferroelectric films, such as low‐dimensional structure, photoconductivity, pyroelectricity, and...

Artificial synaptic devices are the hardware basis of highly efficient neuromorphic networks with low energy consumption. Great challenges still remain in this research field, like improving response speed, reducing energy consumption, and exploring new materials and working principles. In this work, we synthesis a new terthiophene monomer function...

The booming frontier of electrochemistry is radically transforming the landscape of global chemical and energy industry. Most recent advancements in electrocatalyst have been built on trial-and-error, lacking model experiments to illuminate the fundamental factors hidden behind, such as phase, conductivity and surface coordination environment. Here...

Ga2O3‐based solar‐blind photodetectors (PDs) are now attracting more and more attention for their potential application in optical imaging, spatial communication, etc. However, the performance of ever‐reported Ga2O3‐based PDs is still not good enough, strongly affected by either the Ga2O3 crystalline quality or the device structure, which severely...

Broadening the spectral range of photodetectors is an essential topic in photonics. Traditional photodetectors are widely used; however, the realization of ultrabroad spectrum photodetectors remains a challenge. Here, a photodetector constructed by a hybrid quasi‐freestanding structure of organic ferroelectric poly(vinylidene fluoride–trifluoroethy...

Recently, the two-dimensional materials, especially transition metal dichalcogenides (TMDCs) have attracted extensive interest for their potential applications in optoelectronics. Here, we demonstrate a hybrid 2D-0D photodetector, which consists of a single layer or few-layer molybdenum disulfide (MoS2) thin film and a thin layer of core/shell zinc...