Department of Electrical Engineering

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The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

Resistive switching behavior of poly (4-vinylphenol):graphene oxide (PVP:GO) composite and ultrathin HfOx hybrid bilayer was explored for developing high-performance flexible resistive random access memory (RRAM) devices. These devices, fabricated with a PVP:GO equivolume solution spin-coated and atomic layer deposited ultrathin HfOx as an active bilayer, exhibited excellent bipolar switching behavior with set and reset voltages as low as 0.6 and-1.46 V, ION/IOFF of &gt;105, and ac and dc switching endurance of over 1400 and 800 cycles, respectively. The same device configuration realized over a flexible polyethylene terephthalate (PET) substrate exhibited a memory window of &gt;103 even after undergoing large mechanical strain (correspoding to a 5-mm bending radius). In addition, after 150 cumulative cycles of consecutive tensile and compressive strain at a 5-mm bending radius, flexible RRAMs demonstrated a clear memory window of 4 × 103 for 104 s. Overall, the incorporation of GO into the PVP solution resulted in achieving better control over conductive filament (CF) growth and, therefore, improved repeatability and reliability. This article indicates that the strategy of incorporating composite and organic-inorganic active bilayer can lead toward the development of high-performance flexible RRAMs. © 2020 IEEE.

World University root node

IEEE Transactions on Electron Devices

High-Performance Flexible Resistive RAM with PVP:GO Composite and Ultrathin HfOx Hybrid Bilayer

This paper presents an Optical Character Recognition (OCR) system for documents with English text and mathematical expressions. Neural network architectures using CNN layers and/or dense layers achieve high level accuracy in character recognition task. However, these models require large amount of data to train the network, with balanced number of samples for each class. Recognition of mathematical symbols poses challenges of the imbalance and paucity of training data available. To address this issue, we pose the character recognition problem as a Distance Metric Learning problem. We propose a Siamese-CNN Network that learns discriminative features to identify if the two images in a pair contain similar or dissimilar characters. The network is then used to recognize different characters by character matching where test images are compared to sample images of any target class which may or may not be included during training. Thus our model can scale to new symbols easily. The proposed approach is invariant to author’s handwriting. Our model has been tested over images extracted from a dataset of scanned answer scripts collected by us. It is seen that our approach achieves comparable performance to other architectures using convolutional layers or dense layers while using lesser training data. © 2020, Springer Nature Singapore Pte Ltd.

Department of Computer Science & Engineering

Communications in Computer and Information Science

DocDescribor: Digits + Alphabets + Math Symbols - A Complete OCR for Handwritten Documents

Rare Metals

Single-atom catalysts boosted ultrathin film sensors

In this work, the MoS2 functionalized AlGaN/GaN high-electron mobility transistor (HEMT) was utilized for the first time to detect toxic mercury (Hg2+) ions under ultraviolet (UV) illumination. The AlGaN/GaN HEMT was fabricated on the sapphire substrate, and corresponding structural and electrical properties were investigated. Subsequently, the optimization of MoS2 concentration for device functionalization was carried out by performing sensing analysis of Hg2+ ions on three devices, and it was observed that the 20 mg/mL concentration of MoS2 is optimum for the detection of Hg2+ ions. Furthermore, the detection of Hg2+ ions was performed under UV exposure, where the developed sensor showed much-improved sensitivity of $548.07~\mu \text{A}$ /ppb compared with normal light. The comparative analysis indicates the increase of three orders of magnitude in sensitivity under UV irradiation, and it is the highest sensitivity ever observed by the AlGaN/GaN HEMT sensor for Hg2+ ion detection. Moreover, the sensor also exhibits the limit of detection (LoD) of 6.14 parts per trillion (ppt) that is much lower than the World Health Organization (WHO) standard limit for Hg2+ ions in drinking water. Due to the photoexcitation process, the generation of electron-hole pairs provides more binding sites on the MoS2 surface, which results in the ultrasensitive detection of the Hg2+ ions at trace and ultratrace levels. © 1963-2012 IEEE.

Ultrasensitive Detection of Mercury Ions under UV Illumination of MoS2Functionalized AlGaN/GaN Transistor

Nanostructured zinc oxide sensing film was deposited on the Si/SiO2/Pt substrate by the RF magnetron sputtering process. The film was characterized by FESEM (field-emission scanning electron microscope) and XRD (X-ray diffraction) for their morphology and structural analysis. The FESEM results show that the film morphology is in nanophase with an average nanostructure size of ~ 50 nm. XRD results show that the film is polycrystalline. The AFM (atomic force microscopy) and Raman spectroscopy were done to analyze the surface roughness and the structural properties of the film, respectively. FTIR (Fourier-transform infrared spectroscopy) was used to analyze the presence of ZnO. Further, the ZnO nanostructure film has been explored for pH sensing for pH (4–12). The sensitivity of the film was found to be 31.81 mV/pH. The drift characteristics of the film were also done to find out the stability of the film. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

Applied Physics A: Materials Science and Processing

Development of ZnO nanostructure film for pH sensing application

Transition metal dichalcogenide, MoS2 has attracted a lot of attention recently owing to its tunable visible range band gap, and anisotropic electronic and transport properties. Here, we report comprehensive inelastic light scattering measurements on both chemical vapor deposition grown (horizontally and vertically aligned) flakes, and mechanically exfoliated flakes of single crystal MoS2. We probe the anisotropic optical response by studying the polarization dependence intensity of the Raman active phonon modes as a function of different incident photon energy and flake thickness. Our polarization dependent Raman studies reveal strong anisotropic behavior reflected in the anomalous renormalization of the modes intensity as a function of flake thickness, phonons and photon energy. Our observations reflect the strong anisotropic light-matter interaction in this high crystalline symmetric layered MoS2 system, especially for the in-plane vibrations, crucial for understanding as well as future applications of these materials. © 2020 IOP Publishing Ltd.

Fulltext

Journal of Physics Condensed Matter

Anisotropic electron-photon-phonon coupling in layered MoS2

Automated clinical tests that assess quality of geriatric screening tests such as the Five-Times-Sit- To-Stand (5STS) and the Timed-Up-and-Go (TUG) are being designed to assess the decline in functional ability of elderly. The existing techniques to assess the quality of these physical activities include sensor-based techniques including body mounted sensors, force sensors and, vision and imaging sensors. These sensors have their own advantages and disadvantages towards the task of clinical assessment. In this work, we introduce a fusion- based technique to combine multiple sensors leveraging advantages of individual sensors, in such a way that the resulting assessment is more accurate. We evaluate our technique for 5STS test using a fusion of a chair and RGB sensors. In a test of 15 older people, there was no significant difference in performance between the two sensors, obtaining 76% and 73% for the RGB and chair, respectively. However, a significant improvement was obtained for the fusion technique, with 90% accuracy for all the phases of the STS test. The proposed fusion technique was observed to be better than the individual sensor assessment. © 2020 IEEE.

Department of Mathematics

26th National Conference on Communications, NCC 2020

A fusion-based approach to identify the phases of the sit-to-stand test in older people

IET Renewable Power Generation

Framework of maximum power point tracking for solar PV panel using WSPS technique

This article presents the design, development, and characterization of a double-bridge electrostatically actuated micromirror for multiobject spectroscopy (MOS). The proposed structure is an improvement over single-bridge micromirrors in terms of aperture size, pull-in voltage, degrees of freedom, and fill factor. The two-axis symmetric rotation mechanism of the proposed micromirror is achieved by bending and twisting action of the suspended cantilevers which is contrary to the twisting cantilevers of a conventional one-axis torsional micromirror. The placement of anchor and cantilevers under the mirror plate results in a high fill factor when arranged in a 2-D array. The analytical modeling, design optimization, and static and dynamic analysis are done using finite-element method (FEM) in Coventorware. An optimized design is fabricated using a simple approach of surface micromachining and electroplating. For a micromirror of size $200\,\,\mu \text{m}\,\,\times 200\,\,\mu \text{m}$ and the actuation gap of $2.5~\mu \text{m}$ , the device exhibits a tilt angle of 1.5° at a pull-in voltage of 23.1 V, a switching time of $38~\mu \text{s}$ , and the resonance frequency of 35.23 kHz. A ${3} \times {3}$ array of the micromirror is demonstrated with a fill factor of more than 95%. The deflection range can be increased by simply increasing the thickness of the sacrificial layer and without any major process modification. © 1963-2012 IEEE.

Design and Development of a Double-Bridge Micromirror with Bending and Twisting Cantilevers for Multiobject Spectroscopy

Kidney failure is a common disease prevailing in the present generation. Renal disfunction inflict adverse effects on human health that are much fatal. Kidney failure has attracted great attention among the present scientific community. Thus, it is desirable to develop an implantable device to replace the failed kidney that could be partially possible with Kidney-on-Chip technology. This paper presents a Kidney-on-Chip model where size-dependent re-absorption of the kidney is majorly investigated by considering the implications of hydrostatic pressure. The device is comprised of two blood tubules separated by a main tubule in the Centre. The main tubule connects both the blood tubules by the means of transporting channels. The transporting channel allows the flow of solutes from the main tubule to blood tubules depending on size of the solutes. The hydrostatic effect can alter the functioning of the kidney by effecting the cytoskeleton arrangement of kidney cells. Employing hydrostatic effects into the device will make the model more compact and realistic. The analysis was made by employing hindrance in the form of bars arranged in zig–zag fashion in the main tubule forming stepwise structure. Simulation results of presented design have produced an outflow velocity of 9.12 × 10−5 m/s which is greater than 8.2 × 10−5 m/s without hydrostatic effect. The re-absorption rate has been improved from 50 to 55% which is desirable. The mathematical analysis was made to support the simulation results. Different studies were conducted on the device performance by changing the parameters that affect fluid flow such as inflow velocity, density, viscosity, capillary forces, and surface tension. The presented work can produce a bio-reactor for kidney-on-Chip applications with more realistic results. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.