Now showing 1 - 10 of 28
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    CMT based Fast Analytical Model of a Ring Resonator Refractive Index Biosensor
    For detecting skin cancer, a silicon nitride based ring resonator refractive index sensor is modelled using coupled mode theory. This device has a high sensitivity of 249nm/RIU and Q factor of 1310.
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    Enhanced Resistive Switching in Flexible Hybrid RRAM Devices With PVK:MoS2/TiO2Bilayer
    (2023-01-01)
    Saini, Shalu
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    Lodhi, Anil
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    Dwivedi, Anurag
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    High-performance flexible resistive random access memory (RRAM) devices were demonstrated by engineering the switching layer with PVK:MoS2 composite and TiO2 bilayer. These flexible RRAM devices exhibited excellent switching with low SET (1.2 V) and RESET (-1.5 V) voltages, a high repeatability of 1000 cycles, and an excellent retention time of 5000 s with an ON/OFF current ratio more than 102 at a read voltage of 0.2 V, significantly better than neat PVK/TiO2 devices. Moreover, devices with PVK:MoS2/TiO2 bilayer exhibited high stability upon bending with radii up to 7 mm for 100 cycles. Our results indicate that PVK:MoS2/TiO2 composite bilayer can be a promising switching layer candidate for high-performance flexible RRAM devices.
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    Comprehensive Investigation of Shelf Life and Performance of Flexible Hybrid RRAM Devices With PVK:MoS2/TiO2 Bilayer
    (2024-05-01)
    Saini, Shalu
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    Lodhi, Anil
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    Dwivedi, Anurag
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    A comprehensive investigation of long-term environmental stability and performance of flexible hybrid resistive random access memory (RRAM) devices with PVK:MoS2/TiO2 bilayer is presented. These devices were systematically characterized for their switching behavior for a very long duration of 20 months, and it was found that devices were able to maintain their switching behavior with maximum average VSET of 1.5 V and lowest average VRESET of -1.8 V, indicating high shelf life and low-voltage operation. Excellent retention of 104s was exhibited by devices even after being in ambient environment for 20 months. Although the devices exhibited almost unchanged VSET and VRESET values upon variation of humidity exposure (RH 42% to 99%), an increase in the magnitude of both was observed upon temperature variation from room temperature (RT) to 100 °C. A typical decay in IONIOFF by more than an order of magnitude (from 103) was observed upon aging and application of temperature; however, an increase in the same was observed upon exposure to high humidity on the order of 102-103. Our investigation indicates that (PVK:MoS2/TiO2) hybrid switching layer can be suitable for environmentally stable nonvolatile memory devices for flexible electronics.
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    Improving the performance of ring resonator refractive index sensor through structural modifications
    (2024-02-01)
    Kundal, Sanchit
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    In this work, different types of whispering gallery mode ring resonator structures such as strip, slotted, hybrid plasmonic mode, and subwavelength grating ring resonators are simulated using the finite difference time domain method (FDTD). The proposed devices are modeled to be used as refractive index sensor. The comparative analysis of strip, slotted, hybrid plasmonic mode, and subwavelength grating ring resonators is done in terms of sensitivity, Q factor, and figure of merit (FOM) to find out the most suitable device according to the requirement. Additionally, the effect of waveguide width on sensitivity and Q factor is analyzed. The analysis shows that, compared to other simulated whispering gallery mode ring resonator sensor designs, the subwavelength grating ring resonator produces the best sensitivity of 1012 nm/RIU, and the slotted ring resonator produces the best FOM of 1610.
    Scopus© Citations 1
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    A real-time feature-based clustering approach for vibration-based SHM of large structures
    (2024-03-15)
    Prasad, Sneha
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    Kumar, David
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    Feature matching techniques are widely explored in structural health monitoring (SHM) of large structures due to their invariance to scale and rotational changes, unlike the traditionally used template matching techniques. However, uniformity of feature distribution is a major concern while matching the images, which requires a large number of features for better correspondence, increasing the computational time. Thus, this study proposes an intermediate solution — a KAZE feature-based clustering approach. It creates a cluster of only four interest points, which decreases the processing time and enhances the accuracy of detecting pixel displacements. On the other hand, due to the high uncertainty of the corresponding points in all the subsequent images, the study introduces a concept of centroid calculation and centroid prediction for identifying the coordinates responsible for measuring the displacements of large structures. Further, the present work also demonstrates the developed methodology in a real-time SHM experiment by measuring the dynamic response of a structure in real-time.
    Scopus© Citations 2
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    Effect of Nonlinearities on Directed Optical Logic Gates Using Integrated Semiconductor Ring Lasers
    (2020-09-01)
    Nonlinearities in the semiconductor ring laser (SRL) are incorporated in the analysis of directed optical logic gates and their effects on the output are studied. The paper discusses the effects of gain medium linewidth, internal quantum efficiency and self and cross gain saturation on the output of directed optical NOT gate implemented using SRLs.
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    Mathematical modelling of a ring resonator based refractive index sensor for cancer detection
    A silicon microring resonator-based refractive index sensor is proposed using the coupled mode theory (CMT). The ring resonator is decomposed into two bent-straight waveguide coupling regions to obtain a mathematical model. To derive coupled mode equations for the interaction between bent and straight waveguides, the bent mode fields are converted from cylindrical coordinate systems to cartesian coordinates and are solved by using numerical integration. Coupled mode equations between bent and straight waveguides are derived, describing the input and output amplitude related by the scattering matrix. For the fixed dimensions and parameters, the resonant wavelength of the silicon micro-ring resonator structure is computed. The proposed CMT-based ring resonator results are validated with high accuracy with simulation results of FDTD and 2D FEM methods. Compared to FDTD and 2D FEM methods, the CMT-based ring resonator shows a significant reduction in computer resource requirements (time, speed, and memory). The ring resonator-based refractive index sensor for cancer detection applications is proposed with a high sensitivity of 146 nm/Refractive index unit and a Q factor of 3459. Finally, various parameters of the ring resonator are varied to improve sensitivity and Q factor.
    Scopus© Citations 3
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    Design and Modeling of 1 Gbps Directed Optical XOR/OR Gates Using Integrated Semiconductor Ring Lasers
    (2019-07-01)
    A novel design of optical XOR/OR gate operating at 1 Gbps and implemented by directed logic using integrated semiconductor ring lasers is presented. The proposed design is simple to implement with no optical non-linearities required for switching operation. Modeling of proposed logic gates is performed using the rate equations for counter-propagating electric fields inside the ring lasers.
    Scopus© Citations 1
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    Bipolar resistive switching properties of TiO x/graphene oxide doped PVP based bilayer ReRAM
    (2022-04-01)
    Lodhi, Anil
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    Saini, Shalu
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    Dwivedi, Anurag
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    In this paper, firstly, some recently explored promising materials and processes for resistive random access memory (ReRAM) devices with bipolar switching mechanism along with their performance are discussed. Further, resistive switching behaviour of TiO x /graphene oxide (GO):poly(4-vinylphenol) (PVP) based bilayer in ReRAM devices is demonstrated. It was found that bipolar resistive switching behaviour is significantly enhanced by embedding 2D material such as GO in the organic polymer acting as switching layer. ReRAM devices with Ag/PVP:GO/TiO x /fluorine doped tin oxide (FTO) structure exhibited high ON/OFF current ratio (>103), low voltage operation, and high retention time. Bipolar resistive switching from these engineered active layers will have great potential for future large area and sustainable electronics.
    Scopus© Citations 6
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    Flexible Forming Free Resistive Memory Device with 2D Material MoSe2as Switching Layer
    (2023-01-01)
    Saini, Shalu
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    Dwivedi, Anurag
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    Lodhi, Anil
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    In this paper, 2D MoSe2 is demonstrated as a promising active material for forming free flexible RRAM devices. Fabricated Ag/MoSe2/ITO flexible RRAM devices exhibited excellent resistive switching with very low SET/RESET voltages ∼ ± 1 V, high data retention > 104s, on/off current ratios of 102 to 103, and endurance for more than 100 cycles. These results indicate that MoSe2 can be a suitable switching layer candidate for high-performance RRAM devices for flexible and large area electronics.
    Scopus© Citations 3