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Emerging technologies such as neuromorphic computing and nonvolatile memories based on floating gate field-effect transistors (FETs) hold promise for addressing a wide range of artificial intelligence tasks. For example, neuromorphic computing seeks to emulate the human brain's functionality and employs a device that mimics the role of a synapse in the brain. However, achieving a high current ON/OFF ratio for the program and erase states of nonvolatile memory and neuromorphic computing device with a metal gate is necessary. This study demonstrates a multi-functional device based on heterostructures of transition metal dichalcogenides (TMDCs) with a metal floating gate. Five different channel materials (SnS2, WSe2, MoS2, WS2, and MoTe2) were employed, and hexagonal boron nitride (h-BN) was used as a tunneling layer. The study found that n-type SnS2 exhibits high endurance (15,000 cycles), good retention (2.4 × 105 s), and the highest current ON/OFF ratio (∼2.58 × 108) among the materials for the program and erase states. Moreover, the SnS2 device exhibits synaptic behavior and offers highly stable operation at room temperature. Furthermore, the device shows high linearity in both potentiation and depression, with good retention time and repeatable results with low cycle-to-cycle variations. Additionally, the study used an artificial neural network (ANN) for MNIST simulation of image recognition and achieved the highest accuracy of ∼92 % based on the SnS2 synaptic device experimental results. These findings pave the way for developing nonvolatile memory devices and their applications in brain-inspired neuromorphic computing and artificial intelligence systems.

Abstract To avoid the complexity of the circuit for in‐memory computing, simultaneous execution of multiple logic gates (OR, AND, NOR, and NAND) and memory behavior are demonstrated in a single device of oxygen plasma‐treated gallium selenide (GaSe) memtransistor. Resistive switching behavior with RON/ROFF ratio in the range of 104 to 106 is obtained depending on the channel length (150 to 1600 nm). Oxygen plasma treatment on GaSe film created shallow and deep‐level defect states, which exhibit carriers trapping/de‐trapping, that lead to negative and positive photoconductance at positive and negative gate voltages, respectively. This distinguishing feature of gate‐dependent transition of negative to positive photoconductance encourages the execution of four logic gates in the single memory device, which is elusive in conventional memtransistor. Additionally, it is feasible to reversibly switch between two logic gates by just adjusting the gate voltages, e.g., NAND/NOR and AND/NAND. All logic gates presented high stability. Additionally, memtransistor array (1×8) is fabricated and programmed into binary bits representing ASCII (American Standard Code for Information Interchange) code for the uppercase letter “N”. This facile device configuration can provide the functionality of both logic and memory devices for emerging neuromorphic computing.

Abstract The electrical and optical properties of transition metal dichalcogenides (TMDs) can be effectively modulated by tuning their Fermi levels. To develop a carrier-selectable optoelectronic device, we investigated intrinsically p-type MoTe2, which can be changed to n-type by charging a hexagonal boron nitride (h-BN) substrate through the application of a writing voltage using a metal gate under deep ultraviolet light. The n-type part of MoTe2 can be obtained locally using the metal gate pattern, whereas the other parts remain p-type. Furthermore, we can control the transition rate to n-type by applying a different writing voltage (i.e., − 2 to − 10 V), where the n-type characteristics become saturated beyond a certain writing voltage. Thus, MoTe2 was electrostatically doped by a charged h-BN substrate, and it was found that a thicker h-BN substrate was more efficiently photocharged than a thinner one. We also fabricated a p–n diode using a 0.8 nm-thick MoTe2 flake on a 167 nm-thick h-BN substrate, which showed a high rectification ratio of ~ 10−4. Our observations pave the way for expanding the application of TMD-based FETs to diode rectification devices, along with optoelectronic applications.

A metal–organic framework (MOF) is a highly porous material with abundant redox capacitive sites for intercalation/de-intercalation of charges and, hence, is considered promising for electrode materials in supercapacitors. In addition, dopants can introduce defects and alter the electronic structure of the MOF, which can affect its surface reactivity and electrochemical properties. Herein, we report a copper-doped iron-based MOF (Cu@Fe-MOF/NF) thin film obtained via a simple drop-cast route on a 3D-nickel foam (NF) substrate for the supercapacitor application. The as-deposited Cu@Fe-MOF/NF electrodes exhibit a unique micro-sized bipyramidal structure composited with nanoparticles, revealing a high specific capacitance of 420.54 F g−1 at 3 A g−1 which is twice compared to the nano-cuboidal Fe-MOF/NF (210 F g−1). Furthermore, the asymmetric solid-state (ASSSC) supercapacitor device, derived from the assembly of Cu@Fe-MOF/NFǁrGO/NF electrodes, demonstrates superior performance in terms of energy density (44.20 Wh.kg−1) and electrochemical charge–discharge cycling durability with 88% capacitance retention after 5000 cycles. This work, thus, demonstrates a high potentiality of the Cu@Fe-MOF/NF film electrodes in electrochemical energy-storing devices.

Abstract Transparent and flexible diodes could be useful for future transparent electronics. Here such diodes are discussed with electrical breakdown (EBR) comprises of W/ZnO/ITO structure on the polyethylene terephthalate substrates. The three‐layered structure shows rectifying characteristics with low breakdown voltage originated from the Schottky barrier at the W/ZnO (0.8 eV) and the ZnO/ITO (0.1 eV) interfaces. Mechanical endurance is retained after different bending strengths and the rectification ratio is showed stability for 104 cycles without any significant degradation. Steep slope transistors are designed by implementing such diodes in series with the conventional field effect transistors. Such diode plus transistor stack enables field effect transistors with steep subthreshold swing of

Due to its high dielectric constant ( κ ), the BaTiO _3 (BTO) thin film has significant potential as a next-generation dielectric material for metal oxide semiconductor field-effect transistors (MOSFETs). Hence, the evaluation of the BTO thin film etching process is required for such nanoscale device applications. Herein, the etching characteristics and surface properties are examined according to the crystallinity of the BTO thin film. The results demonstrate that the etching rate is low in the high-crystallinity thin film, and the surface residues are much lower than in the low-crystallinity thin film. In particular, the accelerated Cl radicals in the plasma are shown to penetrate more easily into the low-crystallinity thin film than the high-crystallinity thin film. After the etching process, the surface roughness is significantly lower in the high-crystallinity thin film than in the low-crystallinity thin film. This result is expected to provide useful information for the process design of high-performance electronic devices.

Electrochemical recognition of Hg (II) ions utilizing EDTA modified polyaniline (PANI)/Graphene Oxide (GO) composite is reported in the present communication. Graphene Oxide (GO) synthesis was carried out by a modified Hummer’s method. Electrochemical characterizations, namely cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), were performed before and after modification of the composite. The topographies of the PANI/GO composite and EDTA_PANI/GO electrodes were studied using AFM. Roughness parameter values were compared for confirmation of surface modification. Fourier transform infrared spectroscopy (FTIR) was utilized for the compositional analysis of PANI/GO and EDTA_PANI/GO electrodes. The EDTA_PANI/GO composite exhibits sensitivity toward Hg (II) ions when probed using the differential pulse stripping voltammetry (DPSV) technique with a lower detection limit of 2 ppb. EDTA modified SS_PANI/GO composite (PANI/GO composite deposited on a stainless-steel substrate) showed superior sensitivity in the detection of Hg (II) ions. The sensitivity was observed to extend to 1 ppb, which is smaller than the maximum contaminant level (MCL) endorsed by the Environment Protection Agency (EPA, United States).

Organic nonvolatile memory devices have a vital role for the next generation of electrical memory units, due to their large scalability and low-cost fabrication techniques. Here, we show bipolar resistive switching based on an Ag/ZnO/P3HT-PCBM/ITO device in which P3HT-PCBM acts as an organic heterojunction with inorganic ZnO protective layer. The prepared memory device has consistent DC endurance (500 cycles), retention properties (104 s), high ON/OFF ratio (105), and environmental stability. The observation of bipolar resistive switching is attributed to creation and rupture of the Ag filament. In addition, our conductive bridge random access memory (CBRAM) device has adequate regulation of the current compliance leads to multilevel resistive switching of a high data density storage.

The diversity of brain functions depend on the release of neurotransmitters in chemical synapses. The back gated three terminal field effect transistors (FETs) are auspicious candidates for the emulation of biological functions to recognize the proficient neuromorphic computing systems. In order to encourage the hysteresis loops, we treated the bottom side of MoTe2 flake with deep ultraviolet light in ambient conditions. Here, we modulate the short-term and long-term memory effects due to the trapping and de-trapping of electron events in few layers of a MoTe2 transistor. However, MoTe2 FETs are investigated to reveal the time constants of electron trapping/de-trapping while applying the gate-voltage pulses. Our devices exploit the hysteresis effect in the transfer curves of MoTe2 FETs to explore the excitatory/inhibitory post-synaptic currents (EPSC/IPSC), long-term potentiation (LTP), long-term depression (LTD), spike timing/amplitude-dependent plasticity (STDP/SADP), and paired pulse facilitation (PPF). Further, the time constants for potentiation and depression is found to be 0.6 and 0.9 s, respectively which seems plausible for biological synapses. In addition, the change of synaptic weight in MoTe2 conductance is found to be 41% at negative gate pulse and 38% for positive gate pulse, respectively. Our findings can provide an essential role in the advancement of smart neuromorphic electronics.

Aberrant glycosylation is one of the major hallmarks of cancer with altered gene expression signatures of sialyltransferases. ST3Gal-I, a sialyltransferase, is known to play a crucial role in sialylation of T antigen in bladder cancer and it has reported elevated expression in breast carcinogenesis with increased tumor progression stages. The aim of the current study is to develop new monoclonal antibodies (mAbs) against human ST3Gal-I and evaluate their diagnostic potential. We developed a repertoire of stable hybridoma cell lines producing high-affinity IgG antibodies against recombinant human ST3Gal-I, expressed in E. coli BL21-DE3 strain. In order to demonstrate the diagnostic value of the mAbs, various clones were employed for the immunohistochemistry analysis of ST3Gal-I expression in cancerous tissues. Antibodies generated by 7E51C83A10 clone demonstrated a strong and specific fluorescence staining in breast cancer tissue sections and did not exhibit significant background in fibroadenoma sections. In conclusion, the mAbs raised against recombinant ST3Gal-I recognize cellular ST3Gal-I and represent a promising diagnostic tool for the immunodetection of ST3Gal-I expressing cells. Specific-reactivity of clone 7E51C83A10 mAbs towards ST3Gal-I was also confirmed by immunoblotting. Therefore, our observations warrant evaluation of ST3Gal-I as a potential marker for cancer diagnosis at larger scale.