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Field effect transistors based on 2D layered material have gained significant potential in emerging technologies, such as neuromorphic computing and ultrafast memory response for artificial intelligence applications. This study proposes a facile approach to fabricate an optoelectronic artificial synapse for neuromorphic computing and light‐decoding information system by utilizing the 2D heterostructure of CrSBr/PtS2 to overcome circuit complexity. The CrSBr layer serves as a trapping layer, while PtS2, mounted on top of CrSBr, acts as a channel layer. PtS2 exhibits n‐type semiconductor behavior with a hysteresis that varies with the thickness of the underlying CrSBr layer. The heterostructure device, featuring a 96.3 nm thick CrSBr layer, exhibited a large memory window of 11.9 V when the gate voltage is swept from −10 V to +10 V. Various synaptic behaviors are effectively demonstrated, including paired‐pulse facilitation, excitatory postsynaptic current, optical spike number and intensity‐dependent plasticity using laser light at a wavelength of 365 nm. The device achieves 26 distinct output signals depending on the intensity of the incident laser light, ranging from 10 to 385 mW cm−2, enabling its applications for light‐decoded information security systems. Thus, the investigation presents a unique approach to artificial intelligence and cybersecurity systems. [ABSTRACT FROM AUTHOR]

In this article, 2D NbSe2 nanosheets are combined with TiO2 nanoparticles to prepare visible-light active composite photocatalysts using sol gel reflux synthesis. The concentration of NbSe2 is varied as 0.5, 1, 2 and 3 weight percent with respect to TiO2. The prepared samples are characterized via scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), UV–Vis spectroscopy and Brunauer–Emmett–Teller (BET) surface area measurement techniques to determine morphology, dimensional aspects of nanosheets, phase, optical properties and surface area of the nanocomposites, respectively. From SEM images TiO2 nanoparticles are observed on the surface of NbSe2 sheets in all the samples. AFM gives an estimate of thickness of NbSe2 nanosheets ranging from 25 to 40 nm corresponding to 30–50 layers. XRD confirms the presence of both components in nanocomposites. UV–Vis spectrum of NbSe2 nanosheets reveals its visible-light absorption capability and a narrow band gap. The surface area values as obtained from BET technique vary from 120 m2/g for TiO2 NPs alone to 162 m2/g for 2 wt% NbSe2 in TiO2 nanocomposites. To study the visible-light photocatalytic behavior the composites are employed for the photodegradation of rhodamine B (RhB) dye under visible-light irradiation. The prepared nanocomposites substantiate to be highly effective photocatalysts for degradation of organic dye due to visible-light absorption offered by NbSe2 together with increased surface area. The sample having 2 wt% NbSe2 shows best performance with almost complete (i.e., 98%) RhB degradation in just 60 min of visible-light irradiation. NbSe2 can facilitate the increased induction of electrons into the CB of TiO2 by visible-light absorption and higher surface area in composites also adds to substantially improved photocatalytic activity exhibited by the nanocomposites. [ABSTRACT FROM AUTHOR]

The van der Waals (vdW) heterostructures based on two-dimensional (2D) semiconducting materials have been thoroughly investigated with regard to practical applications. Recent studies on 2D materials have reignited attraction in the p-n junction, with promising potential for applications in both electronics and optoelectronics. 2D materials provide exceptional band structural diversity in p-n junction devices, which is rare in regular bulk semiconductors. In this article, we demonstrate a p-n diode based on multiheterostructure configuration, WTe 2 -GaTe-ReSe 2 -WTe 2 , where WTe 2 acts as heterocontact with GaTe/ReSe 2 junction. Our devices with heterocontacts of WTe 2 showed excellent performance in electronic and optoelectronic characteristics as compared to contacts with basic metal electrodes. However, the highest rectification ratio was achieved up to ∼2.09 × 10 6 with the lowest ideality factor of ∼1.23. Moreover, the maximum change in photocurrent ( I ph ) is measured around 312 nA at V ds = 0.5 V. The device showed a high responsivity ( R ) of 4.7 × 10 4 m·AW -1 , maximum external quantum efficiency (EQE) of 2.49 × 10 4 (%), and detectivity ( D *) of 2.1 × 10 11 Jones at wavelength λ = 220 nm. Further, we revealed the bipolar photoresponse mechanisms in WTe 2 -GaTe-ReSe 2 -WTe 2 devices due to band alignment at the interface, which can be modified by applying different gate voltages. Hence, our promising results render heterocontact engineering of the GaTe-ReSe 2 heterostructured diode as an excellent candidate for next-generation optoelectronic logic and neuromorphic computing.

Transition metal dichalcogenides (TMDs) have gained significant attention as next-generation semiconductor materials that could potentially overcome the integration limits of silicon-based electronic devices. However, a challenge in utilizing TMDs as semiconductors is the lack of an established PN doping method to effectively control their electrical properties, unlike those of silicon-based semiconductors. Conventional PN doping methods, such as ion implantation, can induce lattice damage in TMDs. Thus, chemical doping methods that can control the Schottky barrier while minimizing lattice damage are desirable. Here, we focus on the molybdenum ditelluride (2H-MoTe 2 ), which has a hexagonal phase and exhibits ambipolar field-effect transistor (FET) properties due to its direct band gap of 1.1 eV, enabling concurrent transport of electrons and holes. We demonstrate the fabrication of p- or n-type unipolar FETs in ambipolar MoTe 2 FETs using self-assembled monolayers (SAMs) as chemical dopants. Specifically, we employ 1 H ,1 H ,2 H ,2 H perfluorooctyltriethoxysilane and (3-aminopropyl)triethoxysilane as SAMs for chemical doping. The selective SAMs effectively increase the hole and electron charge transport capabilities in MoTe 2 FETs by 18.4- and 4.6-fold, respectively, due to the dipole effect of the SAMs. Furthermore, the Raman shift of MoTe 2 by SAM coating confirms the successful p- and n-type doping. Finally, we demonstrate the fabrication of complementary inverters using SAMs-doped MoTe 2 FETs, which exhibit clear full-swing capability compared to undoped complementary inverters.