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This paper presents an organic memristive device based on the soft and quasi-liquid trypsin biomaterial. Accordingly, trypsin is isolated from the bovine pancreas and deposited on a conducting fluorine-doped tin oxide (FTO) substrate. The current–voltage (I–V) measurements of the trypsin/FTO device show a hysteresis loop at multiple frequencies and voltages. The results demonstrate that the current and resistance of the device can be modulated by altering the frequency and magnitude of the applied signal, suggesting the feasibility of this material for brain-inspired computing devices. The hysteresis area of the device increases in proportion to the frequency of the signal, signifying the inverse-memristive phenomenon. The time-domain flux, time-domain charge, and charge-flux properties are calculated from the experimental I–V data to demonstrate the memristive nature of the trypsin hydrogel. Interestingly, the trypsin hydrogel memristive device mimics bio-synaptic properties such as potentiation–depression and four complex spike-time-dependent plasticity learning rules. Electrochemical studies are performed to understand the electrochemical kinetics of the device. A possible switching mechanism is illustrated to show the memristive effect of the trypsin hydrogel. The results of the present investigation suggest that trypsin can be a possible biomaterial to develop an electronic synaptic device for neuromorphic computing applications.

The massively parallel computing capabilities of the human brain can be mimicked with the help of neuromorphic computing approach and this can be achieved by developing the electronic synaptic device. In the present work, we have synthesized gallium-doped ZnO thin films using a cost-effective hydrothermal method and characterized the thin films using field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Furthermore, gallium-doped ZnO memristive devices were developed using standard procedure and electrically characterized for the neuromorphic application. In particular, resistive switching and synaptic properties of gallium-doped ZnO thin films were investigated. The bipolar resistive switching with an analog memory like behavior was observed in the developed memristive devices. In the present case, good synaptic properties, endurance, and retention characteristics were observed for 0.5% Ga doped memristive device. Our results suggested that the synaptic weight, potentiation-depression, and symmetric Hebbian learning can be tuned with properly engineering the ZnO memristive device with appropriate gallium doping. The detailed analysis of I-V results suggested that resistive switching is occurred due to Ohmic and Schottky conduction mechanisms. Keywords: Memristive device, Resistive switching, Gallium doped ZnO, Electronic synapse, Potentiation and depression, Hebbian learning

In the present investigation, we have experimentally demonstrated the coexistence of filamentary and homogeneous resistive switching mechanisms in single Al/MnO2/SS thin film metal–insulator–metal device. The voltage-induced resistive switching leads to clockwise and counter-clockwise resistive switching effects. The present investigations confirm that the coexistence of both RS mechanisms is dependent on input voltage, charge-flux and time. Furthermore, the non-zero I–V crossing locations and crossovers hysteresis loops suggested that the developed device has memristive and meminductive properties. The memristive and meminductive memory effects are further confirmed by electrochemical impedance spectroscopy. The results suggested that the mem-device dynamics and electrochemical kinetics during different voltage sweeps and sweep rates are responsible for the coexistence of filamentary and homogeneous resistive switching mechanisms as well as memristive and meminductive memory effect in single Al/MnO2/SS metal–insulator–metal device. The coexistence of both RS effects is useful for the development of high-performance resistive memory and electronic synapse devices. Furthermore, the coexistence of memristive and meminductive memory effects is important for the development of adaptive and self-resonating devices and circuits. Published version

In the present work, the hydrothermal approach is employed to develop 1D-TiO2 nanorod array memristive devices and the effect of hydrothermal growth temperature on TiO2 memristive devices is studied. X-ray diffraction (XRD) analysis suggested that the rutile phase is dominant in the developed TiO2 nanorod array. Field emission scanning electron microscopy (FESEM) images show well adherent and pinhole free one dimensional (1D) TiO2 nanorods. The presence of titanium and oxygen in all the samples was confirmed by energy dispersive X-ray spectroscopy (EDS). Furthermore, growth of the 1D TiO2 nanorods depends on the growth temperature and uniform growth is observed at the higher growth temperatures. The well-known memristive hysteresis loop is observed in the TiO2 nanorod thin films. Furthermore, resistive switching voltages, the shape of I-V loops and (non)rectifying behavior changed as the growth temperature varied from 140 °C to 170 °C. The biological synapse properties such as paired-pulse facilitation and short-term depression are observed in some devices. The detailed electrical characterizations suggested that the developed devices show doubled valued charge-magnetic flux characteristic and charge transportation is due to the Ohmic and space charge limited current. Keywords: Memristive device, TiO2, Nanorods, Hydrothermal method, Resistive switching, Neuromorphic computing

In this study, the in situ sol–gel method has been deployed to prepare the titanium dioxide/multiwalled carbon nanotubes (TiO2/MWCNTs) nanocomposite (NCs) powders with varying content of MWCNTs (0.01–1.0 wt %), to construct the dye-sensitized solar cells (DSSCs). First, binder-free NCs were deposited on a transparent-conducting F:SnO2 (FTO) glass substrate by a doctor-blade technique and then anchored with Ru(II)-based dyes to either N719 or ruthenium phthalocyanine (RuPc). The structural and optical properties and interconnectivity of the materials within the composite are investigated thoroughly by various spectral techniques (XRD, XPS, Raman, FT-IR, and UV–vis), electron microscopy (HRTEM), and BET analysis. The experimental results suggest that the ratio of MWCNTs and TiO2 in NCs, morphology, and their interconnectivity influenced their structural, optical, and photovoltaic properties significantly. Finally, the photovoltaic performances of the assembled DSSCs with different content of MWCNTs to TiO2 films anchored with two different dyes were tested under one sun irradiation (100 mW/cm2). The measured current–voltage (IV) curve and incident photon-to-current conversion efficiency (IPCE) spectra of TiO2/0.1 wt % MWCNTs (T@0.1 C) for N719 dye show three times more power conversion efficiency (η = 6.21%) which is opposed to an efficiency (η = 2.07%) of T@0.1 C for RuPc dye under the same operating conditions.

In the present investigation, we have experimentally demonstrated the bipolar resistive switching with the coexistence of three fundamental memelements in the Ag/CoFe2O4/FTO thin film metal-insulator-metal (MIM) device. The device shows the analog resistive switching behavior and charge transport follows the Ohmic and space charge limited conduction (SCLC) mechanisms. The device transforms from asymmetric to symmetric resistive switching when the SCLC conduction mechanism change to the Ohmic conduction mechanism at higher voltage sweep rates. It was observed that the I–V crossing location of MIM device shifted towards the higher voltage range with increasing voltage sweep rates for both bias regions due to the nanobattery effect. The significant tunneling gap between immature conductive filament(s) and percolation channels was responsible for the coexistence of memelements and nanobattery effect in the Ag/CoFe2O4/FTO thin film MIM device.

In order to realize artificial intelligence using an electronic device, it is obligatory to develop a functional solid-state device that mimics synaptic plasticity, analog memory, and forgetting effect exhibited by the biological neurons. In this context, the memristor is an ideal candidate owing to its nonlinearity, passivity, and in-memory computing capabilities. The present work demonstrates the development of a bio-mimicking tungsten trioxide (WO 3 ) memristor device using simple and costs effective spray pyrolysis method. The performance of the developed device was optimized using silver (Ag) doping. Here we show that the analog memory, nature of pinched hysteresis loop, synaptic weights, resistive switching voltages, and forgetting characteristics of spray deposited WO 3 memristor can be systematically tuned by appropriate Ag doping. The effect of Ag doping on the structural, morphological, and electrical characteristics of WO 3 memristor devices was also investigated. The conduction mechanism of the developed devices follows the Ohmic and space charge limited current theories. The results presented in this work are helpful for development and optimization of WO 3 memristor device for the neuromorphic applications.

In this paper, we report the effect of the write voltage and frequency on memristor-based resistive random access memory (RRAM). The above-said parameters have been investigated on the linear drift model of the memristor. With a variation of write voltage from 0.2 to 1.2 V and a subsequent frequency modulation from 1, 2, 4, 10, 100 and 200 Hz, the corresponding effects on memory window, low resistance state (LRS) and high resistance state (HRS) have been reported. Thus, the lifetime (τ) reliability analysis of memristor-based RRAM is carried out using the above results. It is found that the HRS is independent of the write voltage, whereas LRS shows dependency on write voltage and frequency. The simulation results showcase the fact that the memristor possesses higher memory window and lifetime (τ) in the higher voltage with lower frequency region, which has been attributed to less data losses in the memory architecture.

Nanocrystalline, uniform, pentanary mixed metal chalcogenide (PMMC) thin films of copper indium cadmium sulfoselenide (CuInCd(SSe)3) were successfully synthesized using simple, self-organized, arrested precipitation technique in an aqueous alkaline medium. The optical, structural, morphological, compositional and electrical properties of synthesized thin films were investigated as a function indium (In3+) concentration. An optical absorption study revealed that direct allowed transition and band gap energy decreases typically from 1.46 to 1.25 eV. The X-ray diffraction studies revealed that the PMMC thin films have a nanocrystalline nature and crystallite size increases with the increase in the In3+ concentration. Tuning of surface morphology from nanospheres to peas-like morphology with uniform, well-adhered distributed throughout the substrate surface were observed by field emission scanning electron microscopy micrographs. The high-resolution transmission electron microscopy images and selected area electron diffraction pattern were illustrated that compactly interconnected particles with nanocrystalline nature. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy results confirmed that synthesized thin films had an appropriate chemical purity. The electrical conductivity and thermoelectric power measurement indicates that, the films have n-type conductivity. A photoelectrochemical conversion efficiency of 2.40% was achieved with a current density of 2.87 mA/cm2. The developed route may provide an alternative approach to synthesize multinary metal chalcogenide thin-film solar cell. Furthermore, we have developed a predictive model of a CICSSe thin-film solar cell using the artificial neural network. The proposed model is useful for the integrated development environment for the predictive modeling and design of high-efficient solar cells.

Rapid growth of technology and infrastructure has made our lives easier. Whole system allows user's mobility to be tracked using a mobile phone and android Application. A mobile phone application has been developed and deployed on an Android Phone whose responsibility is to track the GPS location and update it to a database. Currently most of the public having their own vehicle, threat of theft is always there at parking or sometimes driving at insecure places. The safety of vehicles is extremely essential for public for which Vehicle tracking and locking system installed in the vehicle, to track the place in case of theft. In this system client just login to vehicle mobile and send you the current location of your vehicle in the form of latitude and longitude along with location name.

In the wake of refurbishment of basic teaching-learning paradigm owing to renaissance of online media we report empirical investigations relating to the curriculum framing. We argue that, no matter how well the instructional model is designed, unless we pay equal consideration towards curriculum, the overall transformational effect will be a void. Based on the scholarly literature survey, we showcase that there are not many studies undertaken in the direction of using curriculum as a change agent in the higher education. We put forth a new model of curriculum framing based on the student academic performance metrics as an input for a meaningful student centric curriculum as an output. Grounded on the conception of Choice based Credit System (CBCS) and prerequisites for the choice, our results evidence, association between the student performances at various subjects as one of the vital parameters for curriculum framing. We adopt the designed framework for a real case study of postgraduate program in Computer Science.

We report simulation of nanostructured memristor device using piecewise linear and nonlinear window functions for RRAM and neuromorphic applications. The linear drift model of memristor has been exploited for the simulation purpose with the linear and non-linear window function as the mathematical and scripting basis. The results evidences that the piecewise linear window function can aptly simulate the memristor characteristics pertaining to RRAM application. However, the nonlinear window function could exhibit the nonlinear phenomenon in simulation only at the lower magnitude of control parameter. This has motivated us to propose a new nonlinear window function for emulating the simulation model of the memristor. Interestingly, the proposed window function is scalable up to f(x)=1 and exhibits the nonlinear behavior at higher magnitude of control parameter. Moreover, the simulation results of proposed nonlinear window function are encouraging and reveals the smooth nonlinear change from LRS to HRS and vice versa and therefore useful for the neuromorphic applications., Comment: 11 pages, 8 figures