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The S vacancy at metal/ MoS 2 interface plays a much important role than the semiconductor itself. In this work, the influence of different configurations of S vacancy concentrations on the effective work function and band structure of the Au/ MoS 2 interface has been investigated systematically using first-principles calculations. The study specifically explores the effective work function of the Au/ MoS 2 interface, the deviation of interface effects from the vacuum work function, and the dipole moment caused by interface charge transfer. The results reveal that the electronic work function of Au/ MoS 2 increases with the increase in S vacancy concentration, but the rate of increase tends to slow down with higher S concentrations. The variation in the effective work function of the Au/ MoS 2 interface may be attributed to the presence of S vacancies and the exposure of Mo atoms. S vacancies lead to a reduction in the Schottky barrier, resulting in increased leakage current. The Fermi pinning caused by S vacancy concentration and location is also observed. The results obtained in this study can serve as a theoretical foundation for applications in electronic devices that rely on metal/ MoS 2 contact. [ABSTRACT FROM AUTHOR]

In this paper, the p-GaN gate AlGaN/GaN high electron mobility transistors (HEMTs) with varying combinations of gate metal work function and gate geometry are fabricated and investigate the influence of gate leakage current (IGS) on the threshold voltage (VTH) and subthreshold swing (SS). The unique dependence of VTH and SS on gate geometry for different metals is observed, which is different from traditional field-effect transistors. A novel hybrid physics model, consisting of the traditional capacitance divider model and hole injection model, is proposed to explain this phenomenon, and the results exhibit an excellent agreement with the experimental data. The holes traverse the gate/p-GaN Schottky barrier by thermal emission or tunneling and inject into the p-GaN layer, generating the IGS. Expanding upon the traditional capacitance divider model, a portion of the injected holes accumulate at the p-GaN/AlGaN interface and induce the corresponding electrons at the AlGaN/GaN heterojunction, which promotes channel conduction. Hence, the transfer curves display the correlation between IGS and VTH as well as SS. The results show that high IGS can alleviate the instability of VTH caused by the lithographic overlay error, and simultaneously optimize SS. This work offers a novel perspective for examining the turn-on mechanism of p-GaN HEMTs, thereby contributing to device design. [ABSTRACT FROM AUTHOR]

We report on the study of electron transport and band offset across β -Ga 2 O 3 /4H-SiC N–n isotype heterojunction. N-type β -Ga 2 O 3 of thickness 2.7 μ m was grown using low-pressure chemical vapor deposition using germanium (Ge) as the dopant on an n-type 4H-SiC substrate. The grown epilayer having (− 201) orientation was verified through XRD. Temperature-dependent I–V and C–V measurements were performed (50–300 K) to investigate the transport properties across the heterojunction. First, lateral diodes were fabricated on β -Ga 2 O 3 , and from C–V, n-doping was estimated to be 2.3 × 10 17 cm − 3 in the epilayer while the Schottky barrier height was estimated to be 1.75 eV. In top-down I–V sweeps, the reverse current across the heterojunction exhibited marginal dependence on temperature, indicating a possible tunnelling-based transport mechanism, while the forward current exhibited an exponential dependence on both temperature and the applied bias. The band diagram indicated the formation of a two-dimensional electron gas (2DEG) at the hetero-interface, which was indirectly confirmed using C–V measurement and TCAD simulation at low temperatures. From the position of the Fermi level in SiC and band diagram, a conduction band offset of 0.4–0.5 eV was estimated between β -Ga 2 O 3 and 4H-SiC. [ABSTRACT FROM AUTHOR]

Pt/GaN Schottky barrier diodes and GaN epitaxial layers on sapphire substrates were studied under swift heavy ion irradiation using 100 MeV O7+ ions having fluences in the range of 1 × 1010–6.4 × 1013 ions/cm2. It was observed that ideality factor, Schottky barrier height, and series resistance increased, while carrier concentration decreased with increasing ion fluence. The ex situ measurements, such as x-ray diffraction and UV–Vis spectroscopy, revealed that GaN layers exhibit negligible variation in structural and bandgap characteristics after irradiation with oxygen ions. The cross-sectional transmission electron microscopy images of the GaN epitaxial layer irradiated at 5 × 1012 ions/cm2 confirmed the absence of irradiation-induced tracks or defect clusters, indicating only point defects that can act as charge traps without structural damage. [ABSTRACT FROM AUTHOR]

The combined feature of high thermal conductivity and high carrier mobility makes cubic boron arsenide (c-BAs) promising for high power and high frequency applications. In BAs-based electronics, the interaction between metals and BAs is crucial, as it significantly affects the electronic properties. One particular parameter is the Schottky barrier height (SBH), which plays a critical role in determining the transmission properties. The interfacial contact effects of BAs (110), (111), and (100) surfaces with a variety of metals have been carefully explored using first-principles calculations in order to characterize their electrical characteristics. For p-type SBHs, over different terminations, there is a strong linear trend with increasing metal work function, with a relatively steeper pinning coefficient of ∼0.2. The results show that the SBHs follow a relation of ϕ n (110) > ϕ n (111) > ϕ n (100). Clear metal induced gap states can be observed at the interfacial BAs, resulting in an enhanced Fermi level pinning effect. The Sc is excellent at generating Schottky contacts with relatively higher SBHs (∼0.9 eV). Pt has the smallest barrier height of ∼0.3 eV, making it ideal for ohmic electrodes with low contact resistance. This work provides insight into the properties at metal–BAs contact interfaces and provides a theoretical basis for the selection of suitable electrodes for high power BAs devices. [ABSTRACT FROM AUTHOR]

The search for contact materials with low contact resistance and tunable Schottky barrier (SB) height of two-dimensional (2D) materials is important for improving the electronic performance. Inspired by the recently synthesized metallic Janus MoSH, this study employs first-principles calculations to investigate the electronic structure, mechanical properties, and interface characteristics of Janus MoSH/GaN and MoHS/GaN van der Waals (vdW) heterostructures. We find that both heterostructures exhibit isotropic mechanical properties and form p-type Schottky barrier contacts (p-ShC) and the SB height of MoHS/GaN is smaller than that of the MoSH/GaN heterostructure. The variation in SB height and contact type under biaxial strain and electric field is also studied for both vdW heterostructures, respectively. Compared to the MoSH/GaN heterostructure, the MoHS/GaN heterostructure can transition to Ohmic contact (OhC) under biaxial strain and electric field, making the S-face contact of MoSH with GaN a more effective contact approach. These findings could provide a new pathway for the design of controllable Schottky nanodevices and high-performance electronic devices on GaN-based vdW heterostructures. [ABSTRACT FROM AUTHOR]

We present a novel method of modeling the contact between a metal and a two-dimensional semiconductor. Using Au on MoS 2 as an example, we self-consistently solve the Schrödinger and Poisson equations and obtain the charge density in the contact. We consider open boundary conditions using the quantum transmitting boundary method and model the electron current through the contact region. We then investigate the effect of effective Schottky barrier height, electrostatic doping, and length of the overlap region on the contact resistance in a top contact geometry. By using data from experiments or from ab initio calculations for the fitting of parameters, such as the effective Schottky barrier height, the model can be used to efficiently obtain the contact resistance and, therefore, the quality of the contact. Furthermore, we investigate the effect of sampling of the Brillouin zone in the transverse direction on the numerical calculation of key quantities, such as contact resistance and free charge density. Additionally, we show that the boundary conditions applied to the Poisson equation during the calculation of the free charge density have a significant impact on the calculated contact resistance and that the impact is more pronounced in heterostructures with a larger Schottky barrier. We found that the contact resistance may be significantly underestimated, by up to one order of magnitude, when the height of the simulation domain is not large enough. [ABSTRACT FROM AUTHOR]

In an interconnected high-vacuum illustration system, the surfaces of p-InGaN/GaN heterostructures grown with integrated metalorganic chemical vapor deposition were treated in O2 gas for different times at room temperature and then transferred to another chamber for fabricating ohmic contacts via sputtering Pd/Pt/Au multi-layers. X-ray photoelectron spectroscopy measurements unveil that the proportions of Ga–O of the treated samples significantly increase compared with that of the as-grown sample, indicating that a thin layer of GaOx forms on the p-InGaN/GaN surface after exposing to oxygen or air atmospheres. Meanwhile, the samples exposed to O2 or air were found to have much higher specific contact resistance, i.e., higher by two orders of magnitude than that of the as-grown sample. The specific contact resistance of the as-grown sample was derived as 9.3 × 10−5 Ω cm2 using the circular transmission line measurement. Furthermore, the Schottky barrier height of the samples was determined from the measured I–V curves with the thermionic field emission model and was revealed to be closely related to surface treatments. Despite the fact that the insulating layer of GaOx was as thin as 1.2–1.4 Å for the samples exposed to oxygen at room temperature, it can act as an extra barrier layer causing significant increase in the specific contact resistance via blocking the tunneling of carriers. Therefore, the effective removal of p-InGaN surface oxide plays a vital role in preparing good ohmic contacts. [ABSTRACT FROM AUTHOR]

Spinodal decomposition (SD) was incorporated into Nb-doped metastable TiO2–SnO2 to achieve giant interfacial polarization. The dielectric characteristics were analyzed using an equivalent circuit involving electron migration, where the SD bulk is given by the universal dielectric response relation. Both the Nb–TiO2 and the Nb–SnO2 layers showed semiconductive behaviors. With increasing SD treatment temperature, the SD volume fraction increased, as did cation interdiffusion at the SD interface, resulting in a large dielectric loss. The optimal SD temperature was determined as 1100 °C, where the Maxwell–Wagner capacitance showed a very high value of 44.6 μF corresponding to the permittivity at the lowest frequency exceeding 106. Such colossal polarization was considered due to an accumulation of trapped electrons at the Schottky barrier at SD layers with different conductivities. [ABSTRACT FROM AUTHOR]

For the transformation of energy conversion and photocatalytic decomposition, photocatalyst-based artificial photosynthesis for solar-to green fuels and environmental treatment has aroused great attention. Herein, a novel ternary heterojunction based on constructing an interaction between 2D-graphitic carbon nitride (CN), 3D-strontium titanate (STO) and Pt nanoparticles (NPs) (2D/3D CN/STO@Pt) is designed for the first time to greatly promote photocatalytic water cracking hydrogen (H 2) evolution in an alkalescent environment, such as triethanolamine (TEO) as well as integrating with Rhodamin B (RhB) decomposition. Under optimized conditions, the H 2 productivity over 3D/2D CN/STO@Pt-3 heterostructures (10,005 μmol h−1 g−1) with an apparent quantum yield of H 2 production approaching 47.5% is found to be ∼29.7, 8.5, 1.1, and 1.5-fold as much as that in the CN, CN/STO, CN/STO@Pt-1, and CN/STO@Pt-5 heterojunctions, respectively. An up to 2.5-fold enhancement in the photocatalytic RhB decomposition rate, obtaining 90% within 60 min under visible-light-driven is observed for 3D/2D CN/STO@Pt-3 heterostructures, surpassing that of other samples. The CN/STO@Pt-3 sample shows the highest degradation rate of 3.5 min−1, which is 1.8, 2.8, 4.27 and 4.9 -time higher than that of the CN/STO@Pt-1, CN/STO@Pt-5, CN, and STO samples, respectively. The improved photocatalytic behavior of the heterogeneous structures could be ascribed to i) the type II-heterojunction between 2D CN and 3D STO; and ii) the creation of the Schottky contacts between semiconductors and Pt NPs. The configuration of the type-II heterojunction formed by the two semiconductors of 2D g-C 3 N 4 and 3D STO contributes to improved light absorption ability, and rapid separation and transfer of photoinduced charges. At the same time, the close junction of Pt establishes the Schottky barrier to facilitate efficient electron transfer in the ternary nanostructures, impeding the quick recombination of photoexcited charge carriers, and offering abundant reactive sites, contributing multiple electron pathways for the photoreaction strategy. Increased photocurrent density from the LSV measurement and a declined in PL intensity confirmed the enhanced interfacial charge separation in the tertiary photocatalyst. Furthermore, the CN/STO@Pt-3 ternary heterostructure presents outstanding photocatalytic performance after five cycles, indicating good stability and reusability. This work gives a valuable modification pathway for the establishing multi-channel charge carrier transport for energy conversion and environmental remediation processes. The diagram showing the photocatalytic activity of CN/STO@Pt heterostructures. [Display omitted] • The novel type II-Schottky structures of CN/STO@Pt were synthesized. • The RhB decomposition obtained 90% within 60 min under visible-light-driven. • The photocatalytic H 2 evolution rates reached 10,005 μmol h−1 g−1. • The photocatalytic activity of the ternary sample remains stable after four cycles. [ABSTRACT FROM AUTHOR]

It is expected that the activity of photocatalysts can remain the same or decrease as little as possible in photocatalysis reaction. Herein, for the first time, a self‐accelerating H2 production activity in a noble‐metal‐free Cu2O/TpPa‐2‐COF photocatalyst is reported. It shows a beginning H2 production rate of 4.41 mmol h−1 g−1 under visible light illuminance, while the activity kept increasing to 27.27 mmol h−1 g−1 after 25 h reaction, which is 6.2 times higher than the beginning activity and reaches a record high. It is confirmed that part of Cu2O in Cu2O/TpPa‐2‐COF in situ transformed to Cu0 in photocatalytic reaction, which acting as cocatalyst promotes the separation of photogenerated charge carriers. Further density functional theory calculations demonstrate that the Schottky barrier height of Cu‐Cu2O (111) interface is much smaller than that of Pt‐Cu2O (111), supporting its more efficient effect than that with Pt as cocatalyst. [ABSTRACT FROM AUTHOR]

Schottky junction barrier is promising to suppress dark current in photodetectors by blocking the tunneling electrons. Due to the Fermi pinning effect, designing the Schottky barrier with a conventional 3D metal/2D semiconductor interface is challenging. Here, it is shown that a 2D semimetal‐semiconductor van der Waals Schottky junction can be utilized to design the near‐ideal Schottky barrier for the high Ion/Ioff ratio photodetectors. It is demonstrated that the experimental barrier height (≈467 meV) of the 1T′‐MoTe2/WS2 Schottky junction can largely follow the Schottky‐Mott rule by effectively resolving the Fermi pinning effect. Such increased barrier height suppresses the thermionic emission (TE) and the tunneling of the electrons. However, for the photo‐generated electron‐hole pairs with the higher energy case, holes cannot be prevented, while most of the electrons with the higher energy can also be easily transferred. The 1T′‐MoTe2/WS2/1T′‐MoTe2 photodetector exhibits the dark current density of 5 × 10−13 A µm−1, a light on/off ratio of 106, a responsivity of 30 A W−1, and a detectivity of 1.82 × 1014 Jones. Modulated Schottky barrier height is adopted to construct a self‐powered 1T′‐MoTe2/WS2/Au photodetector. [ABSTRACT FROM AUTHOR]

Copper ion (Cu2+) pollution poses a serious threat to marine ecology and fisheries. However, the complexity of seawater and its interference factors make the online detection of Cu2+ quite challenging. To address this issue, we introduce the concept of the photo-assisted adjustment barrier effect into electrochemical detection, using it as a driving force to generate electrochemical responses. The Schottky barrier demonstrates a remarkable regulatory influence on the electrochemical response under photoexcitation, facilitating the response through Cu2+ adsorption. We developed a 4-MBA-AuNPs/CdS/FTO composite that serves as a sensitive platform for Cu2+ detection, achieving a detection limit of 70 nM. Notably, the photo-assisted adjustment of the barrier effect effectively counters the interference posed by ions in seawater, ensuring accurate detection. Furthermore, the sensor exhibits a promising recovery rate (99.62–104.9%) in real seawater samples, highlighting its practical applications. This innovative approach utilizing the photo-assisted adjustment barrier effect offers a promising path for developing electrochemical sensors that can withstand interference. [ABSTRACT FROM AUTHOR]

A large depolarization field in single‐domain PbTiO3 is anticipated to drive the spatial separation of photogenerated charge carriers and enable potential active sites for photocatalytic overall water splitting reaction. However, the negatively polarized surface usually cannot provide sufficient active sites for water oxidation to oxygen because of lacking oxygen vacancies, inevitably hindering photocatalytic water splitting reaction. Here, the ferroelectric polarization screening is reconstructed by a heteroepitaxial SrTiO3 film on the positively polarized surface of PbTiO3 nanoplates to generate abundant oxygen vacancies on the negatively polarized surface as active sites for water oxidation. Moreover, it is experimentally and theoretically revealed that the epitaxial SrTiO3 layer on the positively polarized surface is also beneficial for good dispersion of cocatalyst and the formation of low Schottky barrier height at the interface between the heterostructure and the cocatalyst for efficient electron transfer. Compared with pristine PbTiO3, the obtained PbTiO3/SrTiO3 heteroepitaxial structure with the simultaneous regulation of positively and negatively polarized surfaces delivered a greatly enhanced photocatalytic overall water splitting with stoichiometric ratio (2:1) of hydrogen and oxygen evolution by a factor of 15 times. These findings might open up a new avenue for the design of ferroelectric photocatalysts with excellent activity. [ABSTRACT FROM AUTHOR]

The content of free oxygen O ad at the ZnO grain boundaries has an important impact on the double Schottky barrier and electrical properties of ZnO varistors. In this work, Bi–Er–O pre-synthesized (BE) phase (Bi 1- x Er x) 2 O 3 (0.25 < x < 0.455) with high conductivity of O ad was prepared using Bi 2 O 3 and Er 2 O 3 as raw materials, and the effects of the BE phase doping on the phase, grain boundary properties, and electrical properties of ZnO–Bi 2 O 3 –Sb 2 O 3 –Co 2 O 3 –MnO 2 –Cr 2 O 3 –SiO 2 varistors were studied. XRD analysis shows that the lattice constant of the BE phase (Bi 1- x Er x) 2 O 3 is between (Bi 0.75 Er 0.25) 2 O 3 and BiErO 3. With increasing doping content of the BE phase from 0 to 0.75 wt%, part of Er3+ still exists in the form of the BE phase (Bi 1- x Er x) 2 O 3 at the ZnO grain boundaries, and its content increases with increasing doping content of the BE phase. The conductivity of O ad in (Bi 1- x Er x) 2 O 3 is much higher than that in Bi 2 O 3 , resulting in the generation of a large number of negative O′ and O″ at the ZnO grain boundaries, and decreasing concentration of the intrinsic point defect zinc interstice Zn i. So the donor concentration N d decreases, the height of the grain boundary barrier increases, the depletion layer widens, and the electrical properties are improved. By analyzing the low-temperature permittivity spectra, it was calculated that with increasing doping content of the BE phase from 0 to 0.75 wt%, the concentration of oxygen vacancy V O • decreases inappreciably, but the concentration of zinc interstice Zn i • • decreases by about 23%. When the doping amount of the BE phase is 0.75 wt%, the nonlinear coefficient α of the obtained ZnO varistors is 73.9 ± 0.6, and the leakage current density J L is only 0.3 ± 0.1 μA/cm2. This study provides an important reference for improving the electrical properties of ZnO varistors by manipulating the Bi-rich phase structure to improve the double Schottky barrier characteristics. [ABSTRACT FROM AUTHOR]

This Letter reports an investigation of hole transport in p-GaN/AlGaN/GaN heterostructures through experimental and theoretical analyses under varied conditions. Highly non-linear current–voltage (I–V) characteristics, obtained via the linear transmission line method measurements, are utilized for this study. At low bias voltage, the transport can be ascribed to the Schottky nature of the contact, while at high bias, the conduction is observed to be governed by space-charge limited current (SCLC). The Schottky characteristics (Schottky barrier height and non-ideality factor) and the SCLC exponent were analyzed for devices with varying contact spacings and at different high temperatures. The SCLC exponent, m, is in the range of 2 ≤ m ≤ 4 depending on the applied voltage range, revealing the existence of the trap states in the channel region. The findings of this work indicate that the charge injection, field-induced ionization, and trap states in the p-GaN channel are critical factors in the current transport of p-GaN/AlGaN/GaN heterostructure. [ABSTRACT FROM AUTHOR]

Power Schottky barrier diodes (SBDs) face an inherent trade-off between forward conduction loss and reverse blocking capability. This limitation becomes more severe for ultra-wide bandgap (UWBG) SBDs due to the large junction field. A high Schottky barrier is usually required to suppress the reverse leakage current at the price of an increased forward voltage drop (VF). This work demonstrates a Ga2O3 junction barrier Schottky (JBS) diode that employs the embedded p-type NiO grids to move the peak electric field away from the Schottky junction, thereby allowing for the use of an ultra-low barrier TiN Schottky contact. This JBS diode concurrently realizes a low VF of 0.91 V (at forward current of 100 A/cm2) and a high breakdown voltage over 1 kV, with the VF being the lowest in all the reported vertical UWBG power diodes. Based on the device characteristics measured up to 200 °C, we further analyze the power loss of this JBS diode across a wide range of operational duty cycles and temperatures, which is found to outperform the TiN/Ga2O3 SBDs or NiO/Ga2O3 PN diodes. These findings underscore the potential of low-barrier UWBG JBS diodes for high-frequency, high-temperature power electronics applications. [ABSTRACT FROM AUTHOR]

A germanium p-channel Schottky barrier metal–oxide–semiconductor field-effect transistor (SB-MOSFET) with germanium–platinum Schottky contacts is demonstrated experimentally. The fabrication process has a low thermal budget of 450 ° C and requires neither intentional doping nor ion implantation. At a temperature of 4 K, the p-channel SB-MOSFET turns on at a gate voltage of −1.6 V and shows a peak mobility of 500 cm2/V s at a carrier density of 3 × 1012 cm–2. Under high drain–source bias voltages, the device operates in an unconventional mode where the current is limited by the source contact. Injection of carriers from the source contact to the germanium channel is controlled by the gate bias, which modulates the Schottky barrier capacitively. The transconductance in this mode deviates from and is significantly higher than the value expected for a conventional MOSFET with the same geometry, mobility, and capacitance. Based on four-point current–voltage measurements, we present a theoretical band diagram of the device and give a physical picture for the observed high currents and transconductances. [ABSTRACT FROM AUTHOR]

This Letter investigates the effect of barrier regulation by changing compliance current (CC) on resistance switching (RS) modes. The device exhibits bipolar resistive switching (BRS) with low CCs (1, 3, 7, and 12 mA) and complementary resistive switching (CRS) without CC. By analyzing the current conduction mechanism, the variation law of Schottky barrier height under different CCs is studied, and the different RS modes are explained by the degree of nitrogen enrichment in the non-inert electrode. This paper further explores the correlation between BRS and CRS. Endurance tests in different modes show that the device is expected to achieve a multi-mode RS design. [ABSTRACT FROM AUTHOR]

2D field-effect transistors (FETs) fabricated with transition metal dichalcogenide (TMD) materials are a potential replacement for the silicon-based CMOS. However, the lack of advancement in p-type contact is also a key factor hindering TMD-based CMOS applications. The less investigated path towards improving electrical characteristics based on contact geometries with low contact resistance (RC) has also been established. Moreover, finding contact metals to reduce the RC is indeed one of the significant challenges in achieving the above goal. Our research provides the first comparative analysis of the three contact configurations for a WSe2 monolayer with different noble metals (Rh, Ru, and Pd) by employing ab initio density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. From the perspective of the contact topologies, the RC and minimum subthreshold slope (SSMIN) of all the conventional edge contacts are outperformed by the novel non-van der Waals (vdW) sandwich contacts. These non-vdW sandwich contacts reveal that their RC values are below 50 Ω∙μm, attributed to the narrow Schottky barrier widths (SBWs) and low Schottky barrier heights (SBHs). Not only are the RC values dramatically reduced by such novel contacts, but the SSMIN values are lower than 68 mV/dec. The new proposal offers the lowest RC and SSMIN, irrespective of the contact metals. Further considering the metal leads, the WSe2/Rh FETs based on the non-vdW sandwich contacts show a meager RC value of 33 Ω∙μm and an exceptional SSMIN of 63 mV/dec. The two calculated results present the smallest-ever values reported in our study, indicating that the non-vdW sandwich contacts with Rh leads can attain the best-case scenario. In contrast, the symmetric convex edge contacts with Pd leads cause the worst-case degradation, yielding an RC value of 213 Ω∙μm and an SSMIN value of 95 mV/dec. While all the WSe2/Ru FETs exhibit medium performances, the minimal shift in the transfer curves is interestingly advantageous to the circuit operation. Conclusively, the low-RC performances and the desirable SSMIN values are a combination of the contact geometries and metal leads. This innovation, achieved through noble metal leads in conjunction with the novel contact configurations, paves the way for a TMD-based CMOS with ultra-low RC and rapid switching speeds. [ABSTRACT FROM AUTHOR]

Self-powered metal–semiconductor–metal (M–S–M) photodetectors based on Schottky barrier difference have received extensive attention for their excellent photodetection performance. The Schottky barrier difference generally arises from the utilization of different metal electrodes or from variations in thickness across the ends of the two-dimensional materials, both of which represent extremely complex processes and precise control techniques. In this study, we fabricated self-powered photodetectors with a M–S–M structure using two-dimensional WSe2 nanoflakes and Au electrodes. By adjusting the thickness and positioning of the Au electrodes, a substantial difference between the two Schottky contacts of WSe2/Au and Au/WSe2 interfaces is formed due to the large Fermi-level difference between the two electrodes, which makes the M–S–M WSe2 photodetector to be used for self-powered photodetection. When irradiated with a 405 nm wavelength laser, the specific detectivity (D*) can achieve 6.35 × 1012 Jones, and the on/off ratio can reach 8 × 104. Under 808 and 1064 nm irradiation, D* reaches 5.9 × 1011 and 1.4 × 109 Jones, respectively. Furthermore, the M–S–M WSe2 photodetector, prepared on a transparent polyethylene terephthalate substrate, still achieves a D* of 5.1 × 1011 Jones under 808 nm irradiation. The results are expected to introduce an approach for self-powered photodetectors offering low cost, wide detection range, high detection performance, and broad application possibilities. [ABSTRACT FROM AUTHOR]

In this paper the performance of a graphene/perovskite Schottky barrier photodetector is investigated theoretically for detecting infrared radiation within the spectral region of 7.5–10 μm. In order to increase the responsivity of the photodetector plasmon–polaritons are excited in the graphene layer within the specified spectral region with the aid of dielectric grating fabricated inside the photodetector structure. The results show that with the increase of the Fermi energy level in the graphene layer the wavelength where plasmon–polaritons are excited is shifted toward shorter wavelengths. This property enables the photodetector for tunable detection. The excitation of plasmon–polaritons localizes the infrared radiation incident on the photodetector to the graphene layer with a full width at half maximum of ≈12.6 nm. This localization increases the absorbance of the graphene layer considerably at peak detection wavelengths where plasmon–polaritons are excited, so that at peak detection wavelengths the absorbance of the graphene layer inside the photodetector is higher than 20 % while without the excitation of plasmon–polaritons the absorbance of the same layer is below 0.05 %. Due to this effect the responsivities of the photodetector at wavelengths where plasmon–polaritons are excited, increase more than 535 times relative to the case where plasmon–polaritons are not excited. Therefore the excitation of plasmon–polaritons not only increases the responsivity of the photodetector significantly but also enables the photodetector for tunable detection by varying the Fermi energy level in the graphene layer. [ABSTRACT FROM AUTHOR]

[Display omitted] The Schottky contact which is a crucial interface between semiconductors and metals is becoming increasingly significant in nano-semiconductor devices. A Schottky barrier, also known as the energy barrier, controls the depletion width and carrier transport across the metal–semiconductor interface. Controlling or adjusting Schottky barrier height (SBH) has always been a vital issue in the successful operation of any semiconductor device. This review provides a comprehensive overview of the static and dynamic adjustment methods of SBH, with a particular focus on the recent advancements in nano-semiconductor devices. These methods encompass the work function of the metals, interface gap states, surface modification, image-lowering effect, external electric field, light illumination, and piezotronic effect. We also discuss strategies to overcome the Fermi-level pinning effect caused by interface gap states, including van der Waals contact and 1D edge metal contact. Finally, this review concludes with future perspectives in this field. [ABSTRACT FROM AUTHOR]

In our pursuit of high-power terahertz (THz) wave generation, we propose innovative edge-terminated single-drift region (SDR) multi-quantum well (MQW) impact avalanche transit time (IMPATT) structures based on the AlxGa1−xN/GaN/AlxGa1−xN material system, with a fixed aluminum mole fraction of x = 0.3. Two distinct MQW diode configurations, namely p+-n junction-based and Schottky barrier diode structures, were investigated for their THz potential. To enhance reverse breakdown characteristics, we propose employing mesa etching and nitrogen ion implantation for edge termination, mitigating issues related to premature and soft breakdown. The THz performance is comprehensively evaluated through steady-state and high-frequency characterizations using a self-consistent quantum drift-diffusion (SCQDD) model. Our proposed Al0.3Ga0.7N/GaN/Al0.3Ga0.7N MQW diodes, as well as GaN-based single-drift region (SDR) and 3C-SiC/Si/3C-SiC MQW-based double-drift region (DDR) IMPATT diodes, are simulated. The Schottky barrier in the proposed diodes significantly reduces device series resistance, enhancing peak continuous wave power output to approximately 300 mW and DC to THz conversion efficiency to nearly 13% at 1.0 THz. Noise performance analysis reveals that MQW structures within the avalanche zone mitigate noise and improve overall performance. Benchmarking against state-of-the-art THz sources establishes the superiority of our proposed THz sources, highlighting their potential for advancing THz technology and its applications. [ABSTRACT FROM AUTHOR]

The power consumption is challenging the next-generation electronic and optoelectronic devices. In this Letter, the n-type source-gated transistor (SGT) enabled by CdS nanobelt is investigated in detail, demonstrating the expected low power consumption, along with impressive photodetection performance. The SGT is realized by deliberately introducing the Schottky barrier at the source of the staggered-electrode transistor, exhibiting a small saturated voltage (VSAT) of 0.84 ± 0.21 V and a remarkably low power consumption of 7.56 ± 4.01 nW. Under illumination, the as-constructed SGT also shows a low power consumption of 7.58 nW, which is much lower than that of the most reported phototransistors operating in the saturated region. Moreover, the source-gated phototransistor also shows a high responsivity of 2.54 × 103 A W−1 and a high detectivity of 6.72 × 1012 Jones. All results imply that the as-constructed low-power-consumption source-gated phototransistor promises next-generation high-performance electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Heterostructure, which combines robust ferroelectrics and narrow-bandgap semiconductors together, is promising for acquiring both intensive photocurrent and large photovoltage output in photovoltaics; therefore, manipulation of the properties by engineering heterostructure has driven significant research activity. Herein, well-known Aurivillius-type ferroelectric Bi2WO6 and mullite-type Bi2Fe4O9 are chosen, and an excellent platform to investigate the role of ferroelectric-semiconductor heterostructure in tuning the photovoltaic effect is constructed by in situ depositing p-type nanoscale Bi2Fe4O9 onto n-type Bi2WO6 nanonet matrix. The nanonet-supported two-dimensional planar-like heterostructure and its ferroelectric domain switchability are confirmed by atomic force microscopy techniques. Significantly, the desired Bi2WO6/Bi2Fe4O9 film optimizes the key steps from light to electricity, and exhibits a large and stable photovoltaic effect, achieving four/three orders of magnitude enhancement of short-circuit photocurrent density/open-circuit voltage under laser irradiation. Furthermore, electric-field-controlled switchable asymmetric photoresponse and device stability were clearly observed, due to, in particular, Bi2WO6/Bi2Fe4O9 interfacial Schottky barrier formation and its modulation by poling-modified ferroelectric polarization. These findings highlight an important insight to construct diversified heterostructures with multi-functioning performances. [ABSTRACT FROM AUTHOR]

Graphene has attracted considerable interest for next‐generation electronics. However, the absence of natural bandgap has limited the current on/off ratio of graphene‐based transistors. Vertical integration of 2D heterostructures offers a promising approach to address this challenge, enabling high‐current‐density vertical field‐effect transistor (VFET) with large on/off ratio. Here, a triboelectric potential‐powered VFET with a vertical stacked graphene/MoS2 heterostructure and a sliding‐mode triboelectric nanogenerator (TENG) coupled with gate dielectrics are proposed. The tribotronic VFET has an ultrashort channel length in vertical direction, exhibiting excellent current driving capability with an ultrahigh on‐state current density of 950 A cm−2 and a good current on/off ratio of 630. It also demonstrates reconfigurable diode behavior with a rectification ratio over 102. Temperature‐dependent studies are applied to tribotronic devices for the first time, indicating an effective modulation on the Schottky barrier height of 150 meV by the triboelectric potential. A green LED pixel is driven by the tribotronic VFET as a demonstration to work as a tactile interactive light‐emitting device. The demonstrated tribotronic vertical device offers a promising strategy for integrating various 2D layered materials with TENG in vertical direction, enabling 3D integration of low‐power and interactive devices for next‐generation electronics. [ABSTRACT FROM AUTHOR]

Polarization at interfaces is an important loss mechanism for electromagnetic wave (EMW) attenuation, though the motion behavior of carriers in interfaces composed of different types of conductors has yet to be investigated. Tuning the phase structure of transition metal dichalcogenides (TMDs) MS2 (M = Mo, V, W) by organics small molecule intercalation to achieve the modulation of interfacial types is an effective strategy, where 1T‐MS2 exhibits metallic properties and 2H‐MS2 has semiconducting properties. To exclude the contribution of the intrinsic properties of TMDs materials, three TMDs (MoS2, VS2, and WS2), which also possess phase transitions, are investigated. Among them, the 1T‐MS2 composite exhibits excellent EMW absorption performance under the synergistic effect of interfacial polarization and conduction loss. 1T‐MoS2/MOF‐A exhibits the best EMW absorption performance with an RLmin of −61.07 dB at a thickness of 3.0 mm and an EAB of 7.2 GHz at 2.3 mm. The effectiveness of the modulation of the interfacial polarization using 1T‐phase and 2H‐phase MS2 is demonstrated, which is important for the analysis of the carrier motion behavior during the interfacial loss. [ABSTRACT FROM AUTHOR]

Graphene–silicon Schottky diodes are intriguing devices that straddle the border between classical models and two-dimensional ones. Many papers have been published in recent years studying their operation based on the classical model developed for metal–silicon Schottky diodes. However, the results obtained for diode parameters vary widely in some cases showing very large deviations with respect to the expected range. This indicates that our understanding of their operation remains incomplete. When modeling these devices, certain aspects strictly connected with the quantum mechanical features of both graphene and the interface with silicon play a crucial role and must be considered. In particular, the dependence of the graphene Fermi level on carrier density, the relation of the latter with the density of surface states in silicon and the coupling between in-plane and out-of-plane dynamics in graphene are key aspects for the interpretation of their behavior. Within the thermionic regime, we estimate the zero-bias Schottky barrier height and the density of silicon surface states in graphene/type-p silicon diodes by adapting a kown model and extracting ideality index values close to unity. The ohmic regime, beyond the flat band potential, is modeled with an empirical law, and the current density appears to be roughly proportional to the electric field at the silicon interface; moreover, the graphene-to-silicon electron tunneling efficiency drops significantly in the transition from the thermionic to ohmic regime. We attribute these facts to (donor) silicon surface states, which tend to be empty in the ohmic regime. [ABSTRACT FROM AUTHOR]

4H‐SiC based devices have garnered significant interest within the realm of high‐voltage and high‐frequency electronic equipment. Schottky barrier heights (SBHs) play a pivotal role in determining the properties of metal/4H‐SiC contacts and holding significance for electrical performance of 4H‐SiC devices. Herein, the first‐principles method is utilized to investigate the interface properties between various metals (Sc, Mg, Zr, Ag, Al, Ru, Rh, Pd, Ni, Au, Ir, and Pt) and 4H‐SiC. The results reveal an approximate linear relationship between SBH and work function of these metals. Fermi‐level pinning factors are determined to be 0.27 and 0.32 for the Si‐face and C‐face interfaces, respectively. The disparity in pinning factors arises from polarization differences between the two interfaces, which stem from uneven net charge distribution on the Si‐face and C‐face. Meanwhile, the SBH values indicate a strong pinning effect, due to the charge transfer occurring at the metal/4H‐SiC interface. Through further analysis of layer density and differential charge density, the interatomic interaction and charge transfer between metal and SiC atoms are analyzed. This work offers fundamental insights into the structural changes in metal/4H‐SiC interfaces and provides valuable guidance in the potential prediction and optimization of device performance. [ABSTRACT FROM AUTHOR]

Transparent electronics is a burgeoning field with exciting potential for next‐generation "see‐through" devices. The creation of high‐performance fully transparent ultraviolet photodetectors (PDs) is essential for enabling wearable and portable applications. In this study, metal–semiconductor–metal (MSM) type Al‐doped ZnO (AZO)/GaN/AZO and indium tin oxide (ITO)/GaN/ITO‐transparent ultraviolet PDs, are initially designed, utilizing AZO‐ and ITO‐transparent conductive electrodes. In these investigations, it is revealed that AZO and ITO form Ohmic and Schottky contacts, respectively, with GaN. Subsequently, building on these findings, a fully transparent Schottky barrier photodiode (SBPD) is developed for ultraviolet photodetection using AZO/GaN/ITO. The SBPD displays a high responsivity (R) of 1.41 × 103 A W−1, a detectivity (D*) of 6.85 × 1014 Jones, and a photo‐to‐dark current ratio exceeding 1 × 104 at a − 5 V bias. Furthermore, the SBPD demonstrates an ultrahigh responsivity of 1.18 A W−1 at 0 V bias, indicating its potential as a self‐powered device under extreme conditions. In these results, the tremendous potential of the high‐performance and fully transparent GaN‐based SBPD is demonstrated for environmental monitoring, optical communication, military radar, and other fields. [ABSTRACT FROM AUTHOR]

α‐Fe2O3 with suitable band structure, good chemical stability, and easy preparation, is a potential photoanode material. However, the key to enhance the performance of α‐Fe2O3 photoanode is to improve the transport characteristics of bulk carriers. It is expected to form a Schottky barrier to improve the carrier separation efficiency by embedding metal nanoparticles into the matrix, but the process is still challenging. Herein, a strategy of forming the Schottky barrier is shown to improve bulk carrier transport dynamics by embedding laser‐generated Pt nanocrystals in α‐Fe2O3 photoanode, which achieves photocurrent densities of up to 1.16 mA cm−2 at 1.23 VRHE (from original 0.21 mA cm−2). This work provides another way to promote the carrier transfer and separation of α‐Fe2O3, which is of great significance to improve the photoelectrochemical water splitting performance. [ABSTRACT FROM AUTHOR]

Memristors have attracted considerable attention as next-generation devices for logic and neuromorphic computing applications, owing to their high on/off current ratio, low power consumption, and high switching speed. Despite the various excellent characteristics of memristors, they suffer from unstable conductive filament-based switching when applied in real-world applications. To address this issue, the effects of Schottky barrier modulation on device performance, in terms of conduction and failure mechanisms of an Ag/WOx/p-Si memristor, were investigated in this study by varying the silicon (Si) doping concentration. Through the temperature analysis of I–V characteristics, different conduction mechanisms are observed according to the doping concentration and resistance state. Moreover, endurance failure with several doping concentrations is analyzed by using filament overgrowth phenomena. The results of this study are expected to help in the development of devices with characteristics suitable for application. [ABSTRACT FROM AUTHOR]

ZnO varistors are widely employed for overvoltage protections and surge absorptions due to their excellent nonlinear current–voltage characteristics originating from double Schottky barriers (DSBs). In most cases, they are operating under moderate ac voltages, while calculating the transient current responses of DSBs remains a challenge, impeding the development of condition assessments. In this paper, a transient conducting model for the DSB is proposed by quantifying the charge trapping processes of the interface states. The DSB is found to quickly reach a quasi-steady state, where the interfacial charge stabilizes with only small modulations at a relatively high level above the dc equilibrium value, even though the applied ac voltage varies in time and polarity. This is the result of efficient charge trapping and slow de-trapping by grain boundary interface states. For charge compensation under the time-varying voltage, the width of the two depletion regions of the DSB shows periodic changes. The proposed model is validated by a satisfying agreement between experimentally measured current responses and simulation results of ZnO varistors. The findings of this study provide a perspective on investigating the time-varying conducting systems and open avenues for condition assessments of nonlinear conducting devices. [ABSTRACT FROM AUTHOR]

With ultra-wide bandgap and outstanding thermal properties, diamond-based high-power devices have excellent application prospects. The crystal structure and electronic property of the metal/hydrogen-terminated diamond (H-diamond) interfaces have been extensively studied experimentally, but the Schottky barrier height (SBH) theory at the metal/H-diamond interface has not been systematically investigated yet. In this work, SBHs of interfaces formed by H-diamond (111) surfaces with 12 metals (Y, Sc, Mg, Ag, Al, Ti, Cu, Co, Pd, Ni, Au and Pt) are investigated using ab-initio calculations. The fitted curve of the SBH with respect to the metal work function is obtained with a Fermi pinning factor of 0.30, which is close to the empirical value of 0.36. Due to the negative electron affinity of H-diamond, Schottky contacts can be formed with low work function metals, which is useful in device design to regulate the SBH and it is relatively easier to form ohmic contacts with high work function metals, leading to low contact resistances. Our work sheds light on the rational design of diamond-based semiconductor devices with low contact resistances. [ABSTRACT FROM AUTHOR]

We demonstrate that an analog synaptic weight update can be achieved using identical pulses via gradual resistance switching of memristors based on sputter-deposited InGaZnO (IGZO) films. When a positive voltage is applied to the IGZO memristor, oxygen vacancies (V o) are ionized and electrons that serve as dopants are generated. This lowers the Schottky barrier formed at the interface and decreases the resistance. However, a negative voltage provides electrons from the Pd electrode, annihilating the ionized vacancies. As the barrier is reconstructed, the IGZO memristor exhibits a high-resistance state (HRS). As V o plays a crucial role in switching, the effect of the radio frequency (RF) power on the memristor during the IGZO deposition is examined. A physical analysis reveals that the V o concentration in the IGZO is proportional to the RF power, inducing a leaky HRS. However, at the expense of a reduced memory window in the IGZO deposited at a higher power of 200 W, the resultant low-resistance state is reliable over time. The strengthened retention allows the synaptic weights to be linearly decreased even by consecutive negative pulses. Hence, when the IGZO memristors are used for synaptic elements to construct neural networks, a higher recognition accuracy for the MNIST dataset is achieved. [ABSTRACT FROM AUTHOR]

The hybridization of MXene materials and transition metal dichalcogenides has a significant impact on heterojunction properties. The transport properties and electronic structure of heterojunctions of semiconducting MoS2 and metallic MXene Nb2C were studied by integrating density functional theory with non-equilibrium Green's function theory. The hybridization between Nb2C and MoS2 makes the tunneling barrier between the two layers disappear, which can enhance the electron injection efficiency from the Nb2C to the MoS2. Moreover, the Nb2C/MoS2 heterojunction exhibits a conventional n-type Schottky contact with a barrier height of 0.14 eV, which is significantly lower than the barrier height of 0.29 eV at the Ti/MoS2 junction. These factors result in a field-effect transistor with a low contact resistance of 138 Ω· μ m and a higher current of 1.09 mA μ m−1 at a bias voltage of 0.3 V applied between the left and right electrodes. Following the application of gate voltage, the I on/ I off ratio reaches 1266. [ABSTRACT FROM AUTHOR]

High-quality epitaxial BiFeO3 (BFO) films were grown on (001)-, (110)- and (111)-oriented Nb:SrTiO3 (NSTO) substrates by pulsed laser deposition. The type of domain structure can be modulated using BFO ferroelectric films with different crystalline orientations. The ON/OFF ratios obtained in (001)-, (110)- and (111)-oriented Au/BFO/NSTO ferroelectric tunnel junctions (FTJs) are 6 × 103, 3 × 104 and 2 × 105, respectively. Analysis of the I – V curves of tunnelling current and average BFO ferroelectric barrier height proves that the polarization intensity of the BFO films modulates both the ferroelectric barrier and the Schottky barrier profile, which further influences the electronic tunnelling probability in BFO FTJs. This work will be useful for further study on achieving a giant ON/OFF ratio and developing insights into the barrier profile and transport mechanism of metal/ferroelectric/semiconductor-type FTJs. [ABSTRACT FROM AUTHOR]

In this study, in situ prepared multiple semiconducting TiO 2 in a metallic Ti 3 C 2 T x channel were investigated, which were derived from the Ti 3 AlC 2 MAX phase by oxidation treatments. Several tiny TiO 2 particles were in situ formed on the Ti 3 C 2 T x MXene surface when it was heated to 150 °C at ambient conditions. The phase transformation of pristine Ti 3 C 2 T x MXene to oxidized TiO 2 was accelerated when the gas-sensing channel was heated to higher temperatures up to 200 °C, yielding a TiO 2 /Ti 3 C 2 T x composite. The experimental results revealed that the heat-treatment temperature played an important role in the gradual development of the morphology and gas-sensing activity of the TiO 2 /Ti 3 C 2 T x sensing channel. In particular, the optimal heating temperature of the composite resulted in a good response and recovery time for NO 2 molecules. Furthermore, first-principles calculations indicated the good sensing ability of the TiO 2 /Ti 3 C 2 T x composite for NO 2 than for other gases. These results suggest a new strategy for developing gas-sensing ability by forming a Schottky barrier through a simple process. [ABSTRACT FROM AUTHOR]

Due to the difficulty of forming a low Schottky barrier at the interface of a metal/SiC contact, preparing Ohmic contacts is still a key technical problem in developing SiC devices. In this paper, the effects of MoS2 intercalation on the interface properties of metal/SiC (Al, Ag, Ti, Au, and Mg) systems were investigated by first-principles calculation. The calculations show that all the metal/SiC contacts exhibit p-type Schottky contacts with strong Fermi level pinning (FLP) at the interfaces. After inserting a layer of MoS2, the Schottky barrier heights are significantly reduced. All the metal/MoS2/SiC systems are tuned to be n-type Ohmic contacts. By calculating and analyzing electron localization functions, projected band structure, partial density of states, and planar-averaged charge density difference, the Ohmic contact formation mechanism may be due to the saturation of dangling bonds of the SiC surface, the reduction in metal-induced gap states, the formation of interface dipole layer, and the shift of FLP position to the interface of metal/MoS2. [ABSTRACT FROM AUTHOR]

Memristors based on 2D semiconductors hold great promise due to their atomic‐level thickness and tunable optoelectronic properties. However, a significant challenge lies in suppressing the large off‐state current, which leads to additional standby power consumption. Here, a simple and versatile method is presented to address this issue by introducing a thin h‐BN interlayer between 2D semiconductors and the electrodes. The thickness of the h‐BN interlayer serves as a pivotal parameter for modulating the interfacial Schottky barrier, thereby influencing the off‐state current level. This fabricated graphene/α‐In2Se3/h‐BN/Cr‐Au memristor, forming a van der Waals heterostructure, exhibits unipolar resistive switching behavior. Remarkably, the memristor incorporating an 8 nm h‐BN interlayer showcases an ultralow off‐state current of 4.2 × 10−13 A, five orders of magnitude lower than that without the h‐BN interlayer. It also achieves a current switching on/off ratio of up to 109 and realizes 32 distinct resistance states, enabling robust multi‐bit memory capabilities. Excellent stability and durability are maintained due to the self‐encapsulation of the h‐BN interlayer. Furthermore, this method is also applicable to memristors built on HfS2, WS2, and WSe2, highlighting its broad potential for technological applications. [ABSTRACT FROM AUTHOR]

Resistive random access memory (RRAM) crossbar arrays require the highly nonlinear selector with high current density to address a specific memory cell and suppress leakage current through the unselected cell. 3D monolithic integration of RRAM array requires selector devices with a small footprint and low‐temperature processing for ultrahigh‐density data storage. Here, an ultrathin two‐terminal n‐p‐n selector with 2D transition metal dichalcogenides (TMDs) is designed by a low‐temperature transfer method. The van der Waals contact between transferred Au electrodes and TMDs reduces the Fermi level pinning and retains the intrinsic transport behavior of TMDs. The selector with a single type of TMD exhibits a trade‐off between current density and nonlinearity depending on the barrier height. By tuning the Schottky barrier height and controlling the thickness of p‐type WSe2 in MoS2/WSe2/MoS2 n‐p‐n selector for a punch‐through transport, the selector shows high nonlinearity (≈ 230) and high current density (2 × 103 A cm−2) simultaneously. The n‐p‐n selectors are further integrated with a bipolar hexagonal boron nitride memory and calculate the maximum crossbar size of the 2D material‐based one‐selector one‐resistor according to a 10% read margin, which offers the possible realization of future 3D monolithic integration. [ABSTRACT FROM AUTHOR]

In this work, we propose combining a low work function anode metal and junction barrier Schottky structure to simultaneously achieve low turn-on voltage (Von) and high breakdown voltage (BV), which alleviates the dilemma that high BV requires high Schottky barrier height (SBH) and high Von. Molybdenum (Mo) is used to serve as the anode metal to reduce the SBH and facilitate fast turn-on to achieve a low Von. To resolve the low SBH related low BV issue, a p-NiO/n-Ga2O3-based heterojunction structure is used to enhance β-Ga2O3 sidewall depletion during the reverse state to improve the BV. With such a design, a low Von = 0.64 V(@1A/cm2) and a high BV = 2.34 kV as well as a specific on-resistance (Ron,sp) of 5.3 mΩ cm2 are demonstrated on a 10 μm-drift layer with a doping concentration of 1.5 × 1016 cm−3. β-Ga2O3 JBS diodes with low Von = 0.64 V and a power figure of merit of 1.03 GW/cm2 show great potential for future high-voltage and high-efficiency power electronics. [ABSTRACT FROM AUTHOR]

In this study, all-inorganic two-dimensional (2D) perovskite Cs2Pb(SCN)2Br2 was employed in a thin-film vertical structure prototype memristor. The device consisted of a Cs2Pb(SCN)2Br2 film prepared through solution approach, sandwiched between an Ag electrode and a TiO2/FTO substrate bottom electrode. Two types of resistive switching (RS) behaviors were observed within a single device at different temperatures. At room temperature, the dominant control mechanism was the interface Schottky barrier, whereas at higher temperatures, the primary driving force shifted to the conductive channel. The device has an on/off ratio exceeding 103 under the interface control mechanism. The migration of mobile bromine vacancies within the Cs2Pb(SCN)2Br2 film, whose concentration was enhanced by the infiltration and reaction of the Ag active electrode within the Cs2Pb(SCN)2Br2 film, is proposed to be the root cause for both types of RS characteristics. These findings offer insights into the potential application of 2D Cs2Pb(SCN)2Br2 perovskite in RS memory devices. [ABSTRACT FROM AUTHOR]

Among the various molybdenum oxide (MoO x) films, molybdenum dioxide (MoO 2) has gained significant attention as a promising electrode material for metal-insulator capacitors owing to its exceptional crystalline properties and high work function (WF). However, achieving precise atomic layer deposition of MoO 2 films requires careful selection of molybdenum (Mo) precursors and oxidants, given the metastable nature of MoO 2. Furthermore, film properties can vary depending on the oxidation potential of the reactant. In this study, we successfully deposited MoO 2 films by utilizing Mo (NMe 2) 4 as the Mo source, which reacted with an O source (oxygen gas or ozone). MoO x (O 2) and MoO x (O 3) films exhibited significantly different growth rates, measuring approximately 0.23 and 1.36 Å/cycle, respectively. Additionally, MoO x (O 2) and MoO x (O 3) exhibited high WFs of 4.81 and 5.12 eV, respectively. Finally, hydrogen (H 2) annealing induced a monoclinic phase in MoO 2. By contrast, MoO x (O 3) exhibited an orthorhombic structure after both H 2 and O 2 annealing, suggesting that the crystal structure was independent of the annealing atmosphere. These findings highlight the possibility that when a MoO 2 layer that is well crystallized through H 2 treatment is applied as an electrode for dynamic random-access memory(DRAM) capacitors, high-k crystal-inducing effects can be functionalized, and the leakage current can be reduced through the Schottky emission barrier. [ABSTRACT FROM AUTHOR]

The color single‐pixel imaging (SPI) has received significant attention due to its ability to provide more comprehensive real‐world information compared to grayscale imaging. The performance of single‐pixel photodetector is the primary determinant for the quality of color SPI. Silicon‐based Schottky photodiodes provide desirable qualities for the essential requirements of high detectivity in high resolution color SPI. Herein, a novel Mo4/3B2‐XTZ/Si hexagonal micro‐hole array (SiHMA) van der Waals (vdW) Schottky photodiode is first constructed for application in color SPI. The resultant Schottky junction possesses a Schottky barrier height up to 1.18 eV, thus leading to a dark current density of 1.47 × 10−13 A cm−2 and an ultra‐high detectivity of 4.4 × 1014 Jones at zero bias voltage, which are superior to most of Si‐based Schottky photodiodes reported and even some commercial Si photodiodes thus far. Importantly, the high detectivity and low dark current density of the photodiode allow for the use as a photodetector in high resolution Hadamard SPI. Notably, a high‐quality 256 × 256‐pixel color image can be successfully achieved under even 25% sampling rate without an additional filter circuit. This work opens an avenue toward the fabrication of high detectivity Schottky photodiode for high quality color SPI. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskites are widely used in photodetection owing to their high optical absorption coefficients. A variety of research has been conducted on perovskite phototransistors and their optoelectronic properties, but the exploration of the influence of contact resistance remains limited. In this work, we employed the transmission-line method to separate the contact resistance Rc × W (ranging from 4.81 × 104 to 4.77 × 103 Ω cm) and the channel resistance Rch × W (ranging from 1.93 × 104 to 1.16 × 104 Ω cm) of (PEA)2SnI4 perovskite phototransistors at different light intensities (520 nm, ranging from 0 to 2550 μW/cm2). Further analysis reveals that illumination-induced accumulation of charge carriers at the metal/semiconductor interface reduces the Schottky barrier. Approximately 90% of the observed increase in photocurrent can be attributed to the reduction in the contact resistance. Our finding underscores the crucial role of charge injection in influencing perovskite-based phototransistors. [ABSTRACT FROM AUTHOR]

Molten salt synthesis of 1T/2H mixed phase MoS 2 for boosting photocatalytic H 2 evolution performance via Schottky junction under EY-sensitized system. [Display omitted] Clean H 2 fuel obtained from the photocatalytic water splitting to hydrogen reaction could efficiently alleviate current energy crisis and the concomitant environmental pollution problems. Therefore, it is desirable to search for a highly efficient photocatalytic system to decrease the energy barrier of water splitting reaction. Herein, the 1T/2H mixed phase MoS 2 sample with Schottky junction between contact interfaces is developed through molten salt synthesis for photocatalytic hydrogen production under a dye-sensitized system (Eosin Y-TEOA-MoS 2) driven by the visible light. In mixed phase MoS 2 sample, the photogenerated electrons of 2H-phase MoS 2 migrated to the 1T-phase MoS 2 are difficult to jump back because of the existence of Schottky barrier, which greatly suppresses the quenching of EY and therefore results in an enhanced hydrogen evolution performance. Therefore, the optimized MoS 2 sample (MoS 2 -350) has an initial hydrogen evolution rate of 213 μmol h−1 and corresponding apparent quantum yield of 36.1 % at 420 nm, far higher than those of pure Eosin Y. It is strongly confirmed by the steady‐state/time-resolved photoluminescence (PL) spectra and transient photocurrent response experiments. With the assistance of Density functional theory (DFT) calculation, the function of Schottky junction in photocatalytic hydrogen evolution reaction is well explained. In addition, a new and universal method (SVM curve) of judging oxidation or reduction quenching for photosensitizers is proposed. [ABSTRACT FROM AUTHOR]

Semiconducting GaN can realize high performance electronic and power devices owing to its high electron mobility and thermal conductivity where good metal-semiconductor contact is prerequisite. In this work, using thermal atomic layer deposition (ALD), ZnO interlayer was grown at 80°C on GaN and the Pt/ZnO/GaN heterojunctions were electrically characterized. The analyses on the current-voltage (I-V) and capacitance (C-V) data showed that the forward I-V conduction was involved with the inhomogeneous Schottky barrier. The higher density of interface states from I-V data than that from C-V data was attributed to nonuniform distribution of interface states. In addition, high density of interface states caused localized high electric field, caused higher Poole Frenkel emission coefficients than the theoretical one. [ABSTRACT FROM AUTHOR]