Assessing tropical cyclone risk for improving mitigation strategies in Coastal Odisha, India.

Tropical cyclone causes large-scale devastation and destruction in the coastal plains of India, particularly in Odisha, which is the most cyclone-affected state in the country. Tropical cyclones are projected to be more powerful and widespread due to changing climate. Hence, the risk assessment of tropical cyclone is necessary to identify cyclone-risk areas in coastal Odisha which may help in the mitigation of the damages caused by cyclones. Therefore, this study utilizes geospatial techniques to produce a comprehensive risk map posed by tropical cyclones and to estimate the degree of risk for coastal districts of Odisha. For this, we evaluated the district-level cyclone risk for coastal Odisha using multi-criteria decision-making (MCDM) technique by considering 21 parameters for each of the four components of risk, i.e., exposure, hazard, vulnerability, as well as mitigation capacity. For each criterion, thematic raster map layers were created and weighted using a fuzzy analytical hierarchy process (FAHP). We prepared individual risk component maps using weighted overlay techniques and finally integrated all indices to create the risk map. The study shows that 13% area of the study area comes under a very high-risk zone whereas, 25% area comes under a high-risk zone. The central (Cuttack, northern parts of Khordha, and south-western parts of Jajpur district) and the eastern part (most of the parts of Jagatsinghpur, Kendrapara, and northern parts of Puri district) of the study area come under high to very high tropical cyclone impact zone. Almost 67% of the total area is highly vulnerable to tropical cyclones and mainly concentrated near the shoreline. The applied approach and results can assist the local authorities in identifying vulnerable and hazardous locations and developing workable solutions for the mitigation of revised cyclone threats in the coastal districts of Odisha.

Lead induced genotoxicity and hepatotoxicity in zebrafish (Danio rerio) at environmentally relevant concentration: Nrf2-Keap1 regulated stress response and expression of biomarker genes.

Genotoxic and hepatotoxic potentials of Pb at an environmentally relevant concentration (5 ppm) in zebrafish were investigated in the present study. Erythrocytic nuclear abnormality tests revealed the increased frequencies of abnormal erythrocytes after Pb exposure, indicating a strong genotoxic potential of Pb. Multiple stress-related parameters were further evaluated in liver, the major detoxifying organ. Pb caused increased production of ROS, which in turn caused severe oxidative stress. As a result, lipid peroxidation was increased, whereas reduced glutathione level and catalase activity was decreased. Alterations in liver histoarchitecture also served as evidence of Pb-induced hepatotoxicity. Pb-induced ROS stress triggered upregulation of Nrf2, Nqo1, Ho1; downregulation of Keap1, and altered mRNA expressions of Mn-sod, Cu/Zn-sod, gpx1, cyp1a, ucp2 suggesting involvement of Nrf2-Keap1-ARE signaling in cellular defence. Nrf2-keap1 is a sensitive biomarker of Pb-induced ROS stress. Overexpression of Hsp70 and other genes in hepatocytes might help cell survival under oxidative stress generation.

Process modelling and techno-economic analysis of anaerobic digestion of sewage sludge integrated with wet oxidation using a gravity pressure vessel and thermal hydrolysis.

Anaerobic digestion (AD) of sewage sludge is used to biodegrade sewage sludge into biomethane and digestate. With the addition of thermal processes such as thermal hydrolysis (TH) and wet oxidation (WO), AD biodegradability generally improves. Implementation of additional treatment is challenging due to the limitation in the mass and energy balances. Hence, tools such as process simulation can be utilized to predict the input and output around the process. In addition, an economic analysis needs to be conducted to check the economic feasibility. The techno-economic analysis (TEA), an integrated method to evaluate a process scheme through simulation and subsequent economic analysis, is effective in providing a systematic understanding of economic implications and the feasibility of a process by identifying the bottlenecks and uncertainties that have a significant impact on the technology. TEA of AD, especially incorporating the TH or WO using gravity pressure vessel (GPV) technology, is limited in the literature. A comprehensive TEA of the AD and the pre- and post-treatment schemes can be utilized to determine the most feasible pathway for sludge treatment for implementation in the wastewater industry. In this study, TEA for four different scenarios of AD was conducted using Aspen Plus and economic analysis tools: (1) without any pre- or post-treatment, (2) with TH pre-treatment, (3) with 100 % WO post-treatment, and (4) with 20 % partial wet oxidation (PWO) and acid hydrolysis pre- or post-treatment. A simulation model (GPVM) was developed using Aspen Plus to mimic the GPV reactor. The study outcomes showed that Scenario 3 with 100 % WO post-treatment was the most suitable for processing parameters and sludge treatment cost. The sensitivity analysis concluded that operating cost and plant capacity are the dominant factors that impact the plant feasibility significantly.

Orchestration of immune response by innate lymphoid cell subtype 2 at various tumor microenvironment, a suitable target for cancer immunotherapy.

Innate lymphoid cells are a mixed population of cells and critical regulators of our innate immune system. According to recent scientific literature, tissue resident innate lymphoid cell subtype 2 has been recognized as an important player of type 2 inflammatory responses, involved in different human malignancies like pancreatic, lung, acute myeloid leukemia, gastrointestinal tract cancer, etc. The current reports have revealed that, among the three main ILC sub types, subtype 2 (ILC 2), as the key regulator of initiating the type 2 inflammatory responses at the tumor microenvironment (TME). This activation of ILC-2 is a very important step for the specific downstream functioning of ILC-2. Priming of ILC-2 with different chemokines involves different cytokine secretion from the activated ILC-2 like IL-4, IL-5, IL-13, IL-9 which induce type 2 inflammatory responses involved in the complex interaction with other immune cells like NK cell, Cytotoxic T cell, MDSC and Treg cell. At the initial stage, ILC-2 activation through IL-33 may induce the anti-tumorigenic effect mediated by ILC-2/eosinophil axis. However, it is also evident that PDG2 (Prostaglandin D2)-mediated activation of ILC-2 induces the ILC-2/MDSC immune suppressive pro-tumorigenic niche at the TME. Here, in this review, we have summarized the function of ILC-2 on cancer immunity based on recent scientific work which indicates ILC-2 plays a dual role and orchestrates the immune responses toward type 2 immunity in different cancer settings.

Cancer is a complex disease where abnormal growth of body cells destroys the normal functions of affected body tissue. It is also one of the leading causes of death worldwide across every continent. There are more than 100 human cancers have been identified until now. Our body has an immune system, which always fights against any harmful agent including cancer cells, which try to invade our immune system and makes us fall ill. Our immune system consists of different specialized cells termed as immune cells which may involve in the direct killing of the cancer cells or it may indirectly help other cells to do it via complex interactions. Innate lymphoid cell or ILC is such type of immune cells of our immune system. Innate lymphoid cell has three main subtypes ILC-1, ILC-2, ILC-3; however, in the context of cancer development and progression, recently, ILC-2 has been recognized as one of the key players. Thus, in this article, we have summarized the activation and various functions of ILC-2 in different cancer settings which conclude that, ILC-2 can be a reasonably good therapeutic target to combat the devastating disease called cancer.

Efficient delivery of methotrexate to MDA-MB-231 breast cancer cells by a pH-responsive ZnO nanocarrier.

Methotrexate (MTX), an efficient chemotherapy medication is used in treating various malignancies. However, the breast cancer cell line MDA-MB-231 has developed resistance to it due to low levels of the MTX transport protein, and reduced folate carrier (RFC), making it less effective against these cancer cells. Here we designed a very simple, biocompatible, and non-toxic amine-capped ZnO quantum dots to overcome the MTX resistance on the MDA-MB-231 breast cancer cell line. The QD was characterized by HRTEM, DLS EDX, FT-IR, UV-Vis, and Fluorescence spectroscopy. MTX loading onto the QD was confirmed through fluorescence and UV-Vis spectroscopy. Additionally, extensive confocal microscopic investigations were carried out to determine whether the MTX was successfully released on the MDA-MB-231 cell line. It was discovered that QD is a better pH-responsive delivery system than the previous ones because it successfully delivers MTX to the MDA-MB-231 at a higher rate on an acidic pH than it does at a physiological pH. QD also has anticancer activity and can eradicate cancer cells on its own. These factors make the QD to be an effective pH-responsive delivery system that can improve the efficacy of the medication in therapeutic diagnosis.

Large-Scale Complementary Logic Circuit Enabled by Al2O3 Passivation-Induced Carrier Polarity Modulation in Tungsten Diselenide.

Achieving effective polarity control of n- and p-type transistors based on two-dimensional (2D) materials is a critical challenge in the process of integrating transition metal dichalcogenides (TMDC) into complementary metal-oxide semiconductor (CMOS) logic circuits. Herein, we utilized a proficient and nondestructive method of electron-charge transfer to achieve a complete carrier polarity conversion from p-to n-type by depositing a thin layer of aluminum oxide (Al2O3) onto tungsten diselenide (WSe2). By utilizing the Al2O3 passivation layer, we observed precisely tuned n-type behavior in contrast to transistors fabricated on the as-grown WSe2 film without any passivation layer, which display prominent p-type behavior. The polarity-transformed n-type WSe2 transistor from the pristine p-type shows the maximum ON current of ∼0.1 µA accompanied by a high electron mobility of 7 cm2 V-1 s-1 at a drain voltage (VDS) of 1 V. We successfully showcased a homogeneous CMOS inverter utilizing 2D-TMDC which exhibits an impressive voltage gain of 7 at VDD = 5 V. Moreover, this effective polarity control approach was further expanded upon to successfully demonstrate a range of logic circuits such as AND, OR, NAND, NOR logic gates, and SRAM. The proposed methodology possesses significant promise for facilitating the advancement of high-density circuitry components utilizing 2D-TMDC.

Dissecting WASH Assessment Tools and Recommending a Comprehensive Tool for Indian Healthcare Facilities.

Providing adequate Water Sanitation and Hygiene (WASH) in Health Care Facilities (HCFs) has many benefits, including achieving Sustainable Development Goals (SDGs) and Universal Health Coverage (UHC). However, there is a significant shortage of statistics on the status of WASH in Healthcare Facilities (WinHCF), resulting in roadblocks in developing improvement strategies. Further, there is a lack of detailed comparison of WASH components covered in available tools against the standards. The present study aims to dissect the national and international tools for WASH assessment in HCFs to suggest comprehensive WASH indicators. The databases like PubMed, Scopus, ScopeMed, Cochrane and Google Scholar were used to extract the available tools. The assessment process, methodology, and components of national and various international tools were compared and synthesized. A total of seven tools, namely WASH FIT 2, Facet, SARA, SPA, TOOL BOX-II, CDC and Kayakalp, were compared on eight components: water, sanitation, hand hygiene, healthcare waste, environmental cleaning and hygiene, infrastructure, workforce management, policy and protocols. Although most tools have covered the same indicators, the methodology and definitions differ. Few of the tools fail to capture the basic indicators defined by Joint Monitoring Programme (JMP). The critical indicators of policy and protocols are only covered in WASH FIT 2, Kayakalp, and TOOL BOX-II. Likewise, most tools fail to capture the indicator of cleaning, IPC practices and climate resilience. The present review also highlighted the limitations of selected tools regarding definitions, methodology and implementation. Hence, based on the review findings, a comprehensive short tool has been developed to monitor WASH in HCF of India. It comprises all the essential fundamental indicators identified from various tools, and recommended by the JMP service ladder with proper definitions. This tool can be helpful for hospital staff and managers for the routine monitoring of WASH in HCFs and improve the quality of care and IPC practices in HCFs.

Differential detection of aspartic acid in MCF-7 breast cancer cells.

Aspartic acid is a non-essential amino acid obtained in the neuroendocrine tissues of vertebrates and invertebrates. Aspartic acid, a major excitatory neurotransmitter in the mammalian central nervous system, plays a key role in memory and acts in many other normal and abnormal physiological processes. In this work, we have developed an efficient chemosensor (PCF) based on the pyridine-carbazole moiety for the differential detection of aspartic acid in biological systems. PCF has a strong binding affinity towards aspartic acid, with a detection limit in the nanomolar range. The binding stoichiometry of aspartic aid and PCF was obtained as 1 : 1 from a Jobs plot analysis. Furthermore, the efficacy of PCF has been successfully demonstrated in in vitro experiments in MCF-7 breast cancer cells.

Chronic exposure to environmentally relevant concentration of fluoride impairs osteoblast's collagen synthesis and matrix mineralization: Involvement of epigenetic regulation in skeletal fluorosis.

Globally, 200 million people are suffering from toxic manifestations of Fluoride(F), dental and skeletal fluorosis; unfortunately, there is no treatment. To unravel the pathogenesis of skeletal fluorosis, we established fluorosis mice by treating environmentally relevant concentration of F (15 ppm NaF) through drinking water for 4 months. As in skeletal fluorosis, locomotor disability, crippling deformities occur and thus, our hypothesis was F might adversely affects collagen which gives the bone tensile strength. This work inevitably had to be carried out on osteoblast cells, responsible for synthesis, deposition, and mineralization of bone matrix. Isolated osteoblast cells were confirmed by ALP activity and mineralized nodules formation. Expression of collagen Col1a1, Col1a2, COL1A1 was significantly reduced in treated mice. Further, a study revealed the involvement of epigenetic regulation by promoter hypermethylation of Col1a1; expressional alterations of transcription factors, calcium channels and other genes e.g., Cbfa-1, Tgf-ß1, Bmp1, Sp1, Sp7, Nf-Kb p65, Bmp-2, Bglap, Gprc6a and Cav1.2 are associated with impairment of collagen synthesis, deposition and decreased mineralization thus, enfeebling bone health. This study indicates the possible association of epigenetic regulation in skeletal fluorosis. However, no association was found between polymorphisms in the Col1a1 (RsaI, HindIII) and Col1a2 (RsaI, HindIII) genes with fluorosis in mice.

Impact of volatile solids destruction on the shear and solid-liquid separation behaviour of anaerobic digested sludge.

Systematic and comprehensive characterisation of shear and solid-liquid separation properties of sludge across a wide range of solids concentration and volatile solids destruction (VSD) is critical for design and optimization of the anaerobic digestion process. In addition, there is a need for studies at the psychrophilic temperature range as many unheated anaerobic digestion processes are operated under ambient conditions with minimal self-heating. In this study, two digesters were operated at different combinations of operating temperature (15-25 °C) and hydraulic retention time (16-32 d) to ensure a wide range of VSD in the range of 0.42-0.7 was obtained. For shear rheology, the viscosity increased 1.3 to 3.3 times with the increase of VSD from 43 % to 70 %, while other parameters (temperature, VS fraction) having a negligible impact. Analysis of a hypothetical digester indicated that there is an optimum VSD range 65-80 % where increase in viscosity due to the higher VSD is balanced by the decrease in solids concentration. For solid-liquid separation, a thickener model and a filtration model were used. No significant impact of VSD on the solids flux, underflow solids concentrations or specific solids throughput was observed in the thickener and filtration model. However, there was an increase in average cake solids concentration from 21 % to 31 % with increase of VSD from 55 % to 76 %, indicating better dewatering behaviour.

Charge density wave induced nodal lines in LaTe3.

LaTe3 is a non-centrosymmetric material with time reversal symmetry, where the charge density wave is hosted by the Te bilayers. Here, we show that LaTe3 hosts a Kramers nodal line-a twofold degenerate nodal line connecting time reversal-invariant momenta. We use angle-resolved photoemission spectroscopy, density functional theory with an experimentally reported modulated structure, effective band structures calculated by band unfolding, and symmetry arguments to reveal the Kramers nodal line. Furthermore, calculations confirm that the nodal line imposes gapless crossings between the bilayer-split charge density wave-induced shadow bands and the main bands. In excellent agreement with the calculations, spectroscopic data confirm the presence of the Kramers nodal line and show that the crossings traverse the Fermi level. Furthermore, spinless nodal lines-completely gapped out by spin-orbit coupling-are formed by the linear crossings of the shadow and main bands with a high Fermi velocity.

Application of advanced trend analysis techniques with clustering approach for analysing rainfall trend and identification of homogenous rainfall regions in Delhi metropolitan city.

In the era of global urbanization, the cities across the world are experiencing significant change in the climate pattern. However, analysing the trend and pattern of rainfall over the urban areas has a number of challenges such as availability of long-term data as well as the uneven distribution of rain-gauge stations. In this research, the rainfall regionalization approach has been applied along with the advanced statistical techniques for analysing the trend and pattern of rainfall in the Delhi metropolitan city. Fuzzy C-means and K-means clustering techniques have been applied for the identification of homogeneous rainfall regions while innovative trend analysis (ITA) along with the family of Mann-Kendall (MK) tests has been applied for the trend analysis of rainfall. The result shows that in all rain-gauge stations of Delhi, an increasing trend in rainfall has been recorded during 1991-2018. But the rate of increase was low as the trend slope of ITA and Sen's slope in MK tests are low, which varies between 0.03 and 0.05 and 0.01 and 0.16, respectively. Furthermore, none of the rain-gauge stations have experienced a monotonic trend in rainfall as the null hypothesis has not been rejected (p value > 0.05) for any stations. Furthermore, the study shows that ITA has a better performance than the family of MK tests. The findings of this study may be utilized for the urban flood mitigation and solving other issues related to water resources in Delhi and other cities.

Bayesian inference modeling to rank response technologies in arctic marine oil spills.

Marine oil spills have a detrimental effect on aquatic systems. Yet, it is challenging to select appropriate technologies in the Arctic because of limited logistics support, inclement weather conditions, and remoteness, and limited research has been conducted in this direction. This article suggests a method to rank the oil response technologies, including mechanical recovery, chemical dispersant, and in-situ burning, for use in Arctic oil spill risk assessment and preparedness planning. The proposed Preference Learning based Bayesian Inference Modeling offers data-driven ranking of systems by learning a label function and considers factors such as ice covered sea areas, cold weather, and spill volume. A data generation system is developed to produce numerous oil spill scenarios, using a state-of-the-art engineering tool. Results demonstrate that the model, while simple, can efficiently and accurately select the best available technique, making it suitable primarily for marine pollution preparedness and response planning in strategic risk assessments.

Shear and solid-liquid separation behaviour of anaerobic digested sludge across a broad range of solids concentrations.

Due to the non-homogeneous and multiphase nature of anaerobic lagoon constituents, CFD modelling for process optimisation requires continuous functions for shear and solid-liquid separation properties across a large range of solids concentrations. Unfortunately, measurement of existing material properties of anaerobic sludges is limited to only shear or solid-liquid separation, or to a limited solids concentration. In this work, the shear properties of an anaerobic sludge were measured from 0.4 to 12.5 vol%, which corresponds to the solids concentrations seen in lagoons. The sludge showed Newtonian behaviour at 0.4 vol% and Herschel-Bulkley yield stress fluid behaviour for higher concentrations ranging from 0.5 to 12 vol%. We compared multiple approaches to determine relationships between the model fitting parameters of consistency, k, flow index, n, and shear yield stress, τy with solids volume fraction ϕ.The solid-liquid separation properties were measured from sedimentation and filtration experiments to obtain compressibility and permeability properties across all the above-mentioned concentrations, enabling development of hindered velocity sedimentation curves. Comparison to full-scale anaerobic digestate identified that the pilot lagoon sludge had faster sedimentation at a given solids concentration in comparison to the digestate. This is the first study on simultaneous rheological characterisation and solid-liquid separation behaviour of an anaerobic sludge across a wide range of concentrations, thus enabling CFD modelling of the hydrodynamics and performance of anaerobic lagoons.

Formation mechanisms and mechanical properties of anaerobic lagoon scum.

The formation of a floating scum layer on the liquid surface of covered anaerobic lagoons prevents optimal and efficient lagoon operation. Scum can reduce hydraulic retention time, inhibit biogas capture and cause damage to lagoon covers. Managing the negative impact of scum requires understanding what scum is, how it forms and how it consolidates. This paper presents measurements of the physical and mechanical properties of scum and sludge samples from two covered anaerobic lagoons that alternatively treat municipal and abattoir waste. Both scum samples consisted of a large proportion of suspended solids that sank once the sample was diluted, degassed and mixed, indicating that sludge flotation and buoyancy due to biogas generation is a major contributor to scum accumulation. Total and soluble chemical oxygen demand and volatile solids in the scum are approximately 90 % higher than in sludge, which indicates that scum has a large proportion of undigested solids. Fourier-transform infrared spectroscopy demonstrates that scum and sludge have similar organic matter, with both including fats, oils, greases, proteins, and polysaccharides. Scum formation due to gas buoyancy implies that scum accumulation is inevitable and controlling fats, oils, and greases at the source of the wastewater is not enough to stop scum formation. Scum accumulation increases due to buoyancy, which drives scum compaction and increases the strength of the scum, as demonstrated by the measurement of scum compressional rheology. Scum management techniques that disturb the scum layer early enough to release the entrapped gas enable the scum to sink and get digested, thus minimising the impact of scum formation.

Characterising sedimentation velocity of primary waste water solids and effluents.

Sedimentation in waste water is a heavily studied topic, but mainly focused on hindered and compression settling in secondary sludge, a largely monodispersed solids, where bulk sedimentation velocity is effectively described by functions such as double Vesilind (Takacs). However, many waste water solids, including primary sludge and anaerobic digester effluent are polydispersed, for which application of velocity functions is not well understood. These systems are also subject to large concentration gradients, and poor availability of settling velocity functions has limited design and computational fluid dynamic (CFD) analysis of these units. In this work, we assess the use of various sedimentation functions in single and multi-dimensional domains, comparing model results against multiple batch settling tests at a range of high and low concentrations. Both solids concentration and sludge bed height (interface) over time are measured and compared. The method incorporates uncertainty analysis using Monte Carlo regression, DIRECT (dividing rectangles), and Newton optimisation. It was identified that a double Vesilind (Takacs) model was most effective in the dilute regime (<1%v/v), but could not effectively fit high solids concentrations (>1%v/v) without a substantial (50%) decrease in effective maximum sedimentation velocity (V0). Other parameters (Rh, Rp) did not change. A power law velocity model (Diehl) was significantly less predictive at low concentrations, and not significantly better at higher concentrations. The optimised model (with reduction in V0) was tested vs a standard (optimised) double Vesilind velocity model in a simple primary sedimentation unit, and resulted in deviation from -12% to +18% in solids capture prediction from underload to overload (washout) conditions, indicating that the effect is important in CFD based analysis of these systems.

Coexisting Charge-Ordered States with Distinct Driving Mechanisms in Monolayer VSe2.

Thinning crystalline materials to two dimensions (2D) creates a rich playground for electronic phases, including charge, spin, superconducting, and topological order. Bulk materials hosting charge density waves (CDWs), when reduced to ultrathin films, have shown CDW enhancement and tunability. However, charge order confined to only 2D remains elusive. Here we report a distinct charge ordered state emerging in the monolayer limit of 1T-VSe2. Systematic scanning tunneling microscopy experiments reveal that bilayer VSe2 largely retains the bulk electronic structure, hosting a tridirectional CDW. However, monolayer VSe2 ─consistently across distinct substrates─exhibits a dimensional crossover, hosting two CDWs with distinct wavelengths and transition temperatures. Electronic structure calculations reveal that while one CDW is bulk-like and arises from the well-known Peierls mechanism, the other is decidedly unconventional. The observed CDW-lattice decoupling and the emergence of a flat band suggest that the second CDW could arise from enhanced electron-electron interactions in the 2D limit. These findings establish monolayer-VSe2 as a host of coexisting charge orders with distinct origins, and enable the tailoring of electronic phenomena via emergent interactions in 2D materials.

Proximity-Induced Novel Ferromagnetism Accompanied with Resolute Metallicity in NdNiO3 Heterostructure.

Employing X-ray magnetic circular dichroism (XMCD), angle-resolved photoemission spectroscopy (ARPES), and momentum-resolved density fluctuation (MRDF) theory, the magnetic and electronic properties of ultrathin NdNiO3 (NNO) film in proximity to ferromagnetic (FM) La0.67 Sr0.33 MnO3 (LSMO) layer are investigated. The experimental data shows the direct magnetic coupling between the nickelate film and the manganite layer which causes an unusual ferromagnetic (FM) phase in NNO. Moreover, it is shown the metal-insulator transition in the NNO layer, identified by an abrupt suppression of ARPES spectral weight near the Fermi level (EF ), is absent. This observation suggests that the insulating AFM ground state is quenched in proximity to the FM layer. Combining the experimental data (XMCD and AREPS) with the momentum-resolved density fluctuation calculation (MRDF) reveals a direct link between the MIT and the magnetic orders in NNO systems. This work demonstrates that the proximity layer order can be broadly used to modify physical properties and enrich the phase diagram of RENiO3 (RE = rare-earth element).

Polarity Control and Weak Fermi-Level Pinning in PdSe2 Transistors.

Two-dimensional (2D) materials have been considered key materials for the future logic devices due to the excellent electrostatic integrity originating from their ultrathin nature. However, the carrier polarity control of 2D material field-effect transistors (FETs) still remains a challenging issue, hindering the realization of complementary logic function in the 2D material platform. Here, we report a comprehensive study on the electrical characteristics of PdSe2 FETs with different metal contacts. It is found that the carrier polarity in PdSe2 FETs can be modulated simply by changing the metal contact due to the weak Fermi-level pinning in PdSe2. We demonstrate a complementary metal-oxide-semiconductor (CMOS) inverter using the same channel material PdSe2 for n- and p-MOSFETs but with different metal contacts, suggesting the possible realization of PdSe2-based CMOS logic circuits.

Doping-Free All PtSe2 Transistor via Thickness-Modulated Phase Transition.

Achieving a high-quality metal contact on two-dimensional (2D) semiconductors still remains a major challenge due to the strong Fermi level pinning and the absence of an effective doping method. Here, we demonstrate high performance "all-PtSe2" field-effect transistors (FETs) completely free from those issues, enabled by the vertical integration of a metallic thick PtSe2 source/drain onto the semiconducting ultrathin PtSe2 channel. Owing to its inherent thickness-dependent semiconductor-to-metal phase transition, the transferred metallic PtSe2 transforms the underlying semiconducting PtSe2 into metal at the junction. Therefore, a fully metallized source/drain and semiconducting channel could be realized within the same PtSe2 platform. The ultrathin PtSe2 FETs with PtSe2 vdW contact exhibits excellent gate tunability, superior mobility, and high ON current accompanied by one order lower contact resistance compared to conventional Ti/Au contact FETs. Our work provides a new device paradigm with a low resistance PtSe2 vdW contact which can overcome a fundamental bottleneck in 2D nanoelectronics.