Monika Tomar - Academia.edu (original) (raw)

Papers by Monika Tomar

Journal of Applied Physics, 2021

Currently, 2D layered material (2DLM) based heterostructures, also known as van der Waals (vdW) h... more Currently, 2D layered material (2DLM) based heterostructures, also known as van der Waals (vdW) heterostructures, are actively pursued owing to their great potential for optoelectronic applications. They are produced either by vertical stacking of individual layers or via in-plane stitching of 2DLMs. Producing vdW heterostructures with clean interfaces and growing them using direct growth methods are challenging. Herein, we report successful growth of large-area MoS2–WS2 vdW heterostructures (single- to few-monolayer, ML, the thickness of MoS2 and WS2) on oxidized Si (100) substrates using the catalyst-free Pulsed Laser Deposition technique. The in-plane (E12g) and out-of-plane (A1g) Raman-active phonon modes are used to probe the interlayer interactions between the constituent 2D layers. We observe a blueshift of 4.73 (1.63) cm−1 of the A1g peak corresponding to MoS2 (WS2) in the MoS2(1ML)–WS2(1ML) heterostructure compared to 1.27 (0.88) cm−1 for the homo-bilayers. The E12g mode also exhibited blueshift for the heterostructure and redshift for the bilayer of the constituent material. We show that the broadband photodetectors fabricated utilizing in situ grown MoS2–WS2 heterostructures exhibit responsivity, specific detectivity, and current on/off ratio as high as 2.51 × 105 A/W, 4.20 × 1014 Jones, and 1.05 × 105, respectively, under 24 μW/cm2 at 405 nm excitation. The successful fabrication of vdW heterostructures using a simple and scalable direct growth method and excellent photodetector performance pave the way for exploitation of their application potential and offer a playground to test some of the theoretical predictions.

Journal of Materials Science: Materials in Electronics, 2022

In the present work, Li-rich layered Li(Li0.25Co0.37Mn0.38)O2 (LiCMO) material is prepared using ... more In the present work, Li-rich layered Li(Li0.25Co0.37Mn0.38)O2 (LiCMO) material is prepared using sol–gel technique. The effect of calcination temperature on the structural and morphological characteristics of LiCMO is studied. The electrochemical performance of layered LiCMO/graphite (Cell 1) and LiCMO/Li (Cell 2) has been investigated. The charge transfer resistance (Rct), lithium diffusion coefficients, and discharging capacity are found to be 16,242 Ω, 3.89 × 10–11 S−1 cm2, and 5.26 mAhg−1 and 16 Ω, 20.78 × 10–8 S−1 cm2, and 323 mAhg−1 for Cells 1 and 2, respectively. The presence of efficient lithium-ion transfer tendency and minimal kinetic barrier for lithium diffusion results in enhanced electrochemical properties of Cell 2. Appreciable results for (LiCMO/Li) coin cell make it a unique combination of LiCMO as cathode with Li as anode for the high energy density lithium-ion battery.

Springer Proceedings in Materials, 2021

Journal of Physics and Chemistry of Solids, 2022

Abstract The ferromagnetic and ferroelectric laminated structure has been utilized to study the m... more Abstract The ferromagnetic and ferroelectric laminated structure has been utilized to study the magnetoelectric (ME) effect, which holds great potential to fabricate micro-electro-mechanical devices with a high figure of merit. Designed a laminated heterostructure using ribbons of Metglas (Fe–Co–Si–B alloy) having high magnetic permeability and lead-free piezoelectric composites of 0.92(Na0.5Bi0.5)TiO3-0.08BaTiO3 (NBT-BT) to generate the significant magnitude of direct ME voltage. The displacement-voltage measurements of NBT-BT yield a high response showing the nature of the piezoelectricity effect. The strength of ME coupling is determined from the ME voltage coefficient (αME), ME measurements have been carried out in the range of 0–6 kHz frequencies. The magnitude of the direct ME effect was found about 45–50 mV/Oe.cm over a low magnetic field of less than ±8 kOe. The real-time ME effect produced nearly 274.5 and 280.2 mV of ME voltages for the applied field of 200 and 300 Oe, respectively. It shows that the trilayer composite structure may be used as weak magnetic field sensors and energy harvesters.

Proceedings IMCS 2012, 2012

Gas sensor structure based on rf sputtered SnO 2 thin film is found to be highly sensitive (1.4x1... more Gas sensor structure based on rf sputtered SnO 2 thin film is found to be highly sensitive (1.4x10 4) towards 100 ppm NO 2 gas, but with slow response (~4min.) and recovery (~33min.) times. To improve the response and recovery speeds of the sensor, different catalysts (WO 3 , TeO 2 , Al 2 O 3 , NiO, CuO and In 2 O 3) in the form of nanoclusters have been deposited over SnO 2 surface and their effect towards sensing response characteristics of NO 2 gas has been studied. Amongst all the catalysts WO 3 nanoclusters are found to be yielding a high response (5.1x10 4) for low concentration of NO 2 gas at a low operating temperature of 100 o C with a fast response and recovery times of 67sec and 17 min respectively.

Proceedings IMCS 2012, 2012

Ammonia sensing response characteristics of the Surface Acoustic Wave (SAW) sensors having differ... more Ammonia sensing response characteristics of the Surface Acoustic Wave (SAW) sensors having different oxide thin films (ZnO, TeO 2 , SnO 2 and TiO 2) deposited by RF sputtering technique under the optimized parameters as sensing layer have been studied. SAW sensor with ZnO sensing layer is found to be exhibiting the maximum response towards liquor ammonia as compared to other oxides. The SAW sensor structure showed a peculiar bidirectional shift (increase or decrease) in frequency on exposure to liquor ammonia vapors, while other VOCs (volatile organic compounds) and gases in the presence and absence of water vapors showed poor response indicating the excellent selectivity of the prepared sensors towards ammonia. Further interaction of liquor ammonia is a one step process involving adsorption of ammonia and water vapors simultaneously.

Journal of Alloys and Compounds, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

IEEE Transactions on Electron Devices, 2018

In this paper, lamb wave acoustic (LWA) devices based on ZnO/Si plate of 30-µm thickness have bee... more In this paper, lamb wave acoustic (LWA) devices based on ZnO/Si plate of 30-µm thickness have been fabricated. Devices with four different designs having acoustic wavelengths of 20, 40, 60, and 80 µm have been fabricated to study its effect on the acoustic velocity for both the lowest order antisymmetric (A 0) and symmetric (S 0) modes. The variation in effective phase difference in all the fabricated LWA devices is studied. An optimum device design is identified with appropriate distance between centers of the input and output IDTs to obtain a phase difference of 180°in antisymmetric and symmetric modes. The obtained phase difference of 180°is very critical in fabricating an oscillator for realization of wireless sensor devices. LWA devices offer high sensitivity to mass loading and thus hold tremendous potential for chemical sensing applications.

Composites Science and Technology, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Process Biochemistry, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Optics & Laser Technology, 2020

Abstract Present article demonstrates the enhanced dynamically tuneable EO modulation characteris... more Abstract Present article demonstrates the enhanced dynamically tuneable EO modulation characteristics in ferroelectric Strontium Barium Niobate S B N , S r 0.6 B a 0.4 N b 2 O 6 thin film modulator based on waveguide coupled surface plasmon resonance. The alternating modulating signals having broad frequency range (1 kHz to 10 MHz) with varying amplitude ( 40 k V / c m to 400 k V / c m ) was applied to estimate the resonance frequency (~1 MHz) using differential modulated intensity interrogation signal. A high value of EO coefficient r = 310 p m / V leading to Modulation index of 56% was achieved with sensitivity of about 0.33 at resonance possessing a characteristics length of 54.64 μm. These waveguide modes coupled with the plasmon modes paves a way for development of EO modulators utilizing materials with high losses. Therefore, a thin film based WCSPR-EO modulator with compact footprint, low operation voltage, broad operation spectrum and faster speed of modulation was fabricated which paves the way for on-chip optical communications.

Materials Science in Semiconductor Processing, 2020

The ferroelectric photovoltaic response characteristics of Lead Zirconate Titanate (PZT) thin fil... more The ferroelectric photovoltaic response characteristics of Lead Zirconate Titanate (PZT) thin film in metal-ferroelectric-metal (MFM) configuration is studied under 33 mode upon exposure to UV radiations. PZT thin films of 180 nm are prepared on inter-digital electrodes patterned silicon substrate (with silicon dioxide as insulating layer) using chemical solution deposition (CSD) technique followed by rapid thermal annealing. PZT thin films are found to be in single phase and possess high electrical polarization (50μC/cm 2). Significant increase in photocurrent and large value of open circuit voltage (1.0 V) is observed for the prepared ferroelectric photovoltaic film under UV illumination.

RSC Advances, 2019

Acrylonitrile-butadiene-styrene (ABS) composites were prepared by dry mixing equal-quantity (20 w... more Acrylonitrile-butadiene-styrene (ABS) composites were prepared by dry mixing equal-quantity (20 wt%) charcoals treated at different temperatures followed by hot compression.

Applied Physics B, 2019

The present work discusses about the modulation of input laser signal using electro-optic (EO) ef... more The present work discusses about the modulation of input laser signal using electro-optic (EO) effect in lithium niobate (LN) crystal. EO properties of LN crystal have been studied using Senarmont compensation method. Further, aiming towards the applicability of this technique in thin films, an optical waveguide has been fabricated in proton-exchanged LN (PE-LN) using prism coupling technique. Dynamic variation of the EO coefficient of PE-LN has been studied utilizing an optical waveguide with Senarmont compensation method.

Integrated Ferroelectrics, 2018

In the present work efforts have been made to develop microheater integrated gas sensors with low... more In the present work efforts have been made to develop microheater integrated gas sensors with low power consumption. The design and simulation of a single-cell microheater is carried out using ANSYS. Low power consumption (<35 mW) platinum micro-heater has been fabricated using bulk micromachining technique on silicon dioxide membrane (1.5 lm thin), which provided improved thermal isolation of the active area of 250 Â 250 lm 2. The micro-heater has achieved a maximum temperature of 950Catanapplieddcvoltageof2.5V.Fabricatedmircro−heaterhasbeenintegratedwithSnO2basedgassensorsfortheefficientdetectionofH2andNO2gases.Thedevelopedsensorswerefoundtoyieldthemaximumsensingresponseof950 C at an applied dc voltage of 2.5 V. Fabricated mircro-heater has been integrated with SnO 2 based gas sensors for the efficient detection of H 2 and NO 2 gases. The developed sensors were found to yield the maximum sensing response of 950Catanapplieddcvoltageof2.5V.Fabricatedmircro−heaterhasbeenintegratedwithSnO2basedgassensorsfortheefficientdetectionofH2andNO2gases.Thedevelopedsensorswerefoundtoyieldthemaximumsensingresponseof184 and $2.1 with low power consumption of 29.18 and 34.53 mW towards the detection of 1 ppm of NO 2 gas and 500 ppm of H 2 gas, respectively.

Microsystem Technologies, 2019

An effort has been made to develop a micro-cantilever using MEMS technology for the realization o... more An effort has been made to develop a micro-cantilever using MEMS technology for the realization of piezoelectric energy harvester. For the fabrication of micro-cantilever, a membrane of SiO 2 of thickness 1.8 lm has been integrated with piezoelectric PZT thin film and gold inter digital transducers (IDTs). MEMS based micro-cantilever with three different dimensions having cantilever lengths of 200 lm, 300 lm and 400 lm have been designed and fabricated for the realization of energy harvesters. The actuating frequency has been found to be varying with length of cantilever. The experimentally observed resonating frequencies of all prepared piezoelectric cantilevers have been validated with the theoretical simulations carried out using COMSOL multiphysics software.

Ceramics International, 2019

In this work, group II-VI metal oxide thin films of cadmium zinc oxide (Cd x Zn 1-x O), have been... more In this work, group II-VI metal oxide thin films of cadmium zinc oxide (Cd x Zn 1-x O), have been deposited using pulsed laser deposition (PLD) growth technique in an oxygen-deficient environment. The effect of cadmium content on structural, optical and electrical properties of the prepared Cd x Zn 1-x O film samples has been delineated by way of varying CdO composition in ceramic target samples. All film samples grown at substrate temperatures of 200-500 °C are revealed to have single phase wurtzite structure with a preferential orientation along (002) plane. By slightly incrementing the substrate temperature from 250 °C to 300 °C in the PLD chamber, the growth process has been further mapped out to investigate changes in said properties. XRD observations are further confirmed by Raman studies, which revealed E 2 (low), E 2 (high) and A 1 (LO) modes for all samples. Enhancement in Cd-content is found to promote the degree of crystallinity in film samples, as suggested by atomic force microscopy images. The optical band gap is estimated at 3.26, 3.16 and 3.12 eV, respectively for increasing atomic cadmium concentration in Cd x Zn 1-x O film samples deposited at 250 °C. Importantly, low resistivity films with resistivities in the order of 10-2-10-3 Ω-cm were obtained, while electron mobility showed an increasing trend with respect to the presence of cadmium content in films. PL measurements were conducted in order to unravel the origin of n-type conductivity in Cd x Zn 1-x O films. This study brings to focus growth aspects of the Cd x Zn 1-x O material system required for the development of thin film heterostructures for optoelectronic applications.

Ceramics International, 2018

Effect of non-magnetic Al 3+ doping on structural, optical, electrical, dielectric and magnetic p... more Effect of non-magnetic Al 3+ doping on structural, optical, electrical, dielectric and magnetic properties of BiFeO 3 ceramics, Ceramics International,

Sensors and Actuators B: Chemical, 2017

Highlights  CO gas sensing response studies of the rf magnetron sputtered ZnO thin films have be... more Highlights  CO gas sensing response studies of the rf magnetron sputtered ZnO thin films have been performed using SPR.  The effect of deposition temperature on the structural, surface morphological, and gas sensing properties of ZnO thin film have been studied.  The developed sensor shows a quick response (1 s) and high sensitivity (0.091 /ppm) towards CO gas.

Nanotechnology, Jan 20, 2017

Present work is focused on the growth and modification of the columnar nanostructures of SnO2 usi... more Present work is focused on the growth and modification of the columnar nanostructures of SnO2 using Glancing Angle Deposition (GLAD) assisted rf sputtering technique for low temperature detection of carbon monoxide (CO) gas. GLAD angle and deposition pressure have been optimized to tailor the grow of columnar nanostructures of SnO2, which exhibited enhanced gas sensing response of 1.49×102 towards 500 ppm of CO gas at a comparatively lower operating temperature of 110°C. The enhanced sensing response at low operating temperature is related to the growth of nanoporous columnar structures of SnO2 thin film under GLAD configuration which results in an enhanced interaction of target CO gas molecules with the large surface area of sensing SnO2 thin film. The origin of sensing mechanism supporting the observed response characteristics towards CO gas has been identified and discussed in detail.

Journal of Applied Physics, 2021

Currently, 2D layered material (2DLM) based heterostructures, also known as van der Waals (vdW) h... more Currently, 2D layered material (2DLM) based heterostructures, also known as van der Waals (vdW) heterostructures, are actively pursued owing to their great potential for optoelectronic applications. They are produced either by vertical stacking of individual layers or via in-plane stitching of 2DLMs. Producing vdW heterostructures with clean interfaces and growing them using direct growth methods are challenging. Herein, we report successful growth of large-area MoS2–WS2 vdW heterostructures (single- to few-monolayer, ML, the thickness of MoS2 and WS2) on oxidized Si (100) substrates using the catalyst-free Pulsed Laser Deposition technique. The in-plane (E12g) and out-of-plane (A1g) Raman-active phonon modes are used to probe the interlayer interactions between the constituent 2D layers. We observe a blueshift of 4.73 (1.63) cm−1 of the A1g peak corresponding to MoS2 (WS2) in the MoS2(1ML)–WS2(1ML) heterostructure compared to 1.27 (0.88) cm−1 for the homo-bilayers. The E12g mode also exhibited blueshift for the heterostructure and redshift for the bilayer of the constituent material. We show that the broadband photodetectors fabricated utilizing in situ grown MoS2–WS2 heterostructures exhibit responsivity, specific detectivity, and current on/off ratio as high as 2.51 × 105 A/W, 4.20 × 1014 Jones, and 1.05 × 105, respectively, under 24 μW/cm2 at 405 nm excitation. The successful fabrication of vdW heterostructures using a simple and scalable direct growth method and excellent photodetector performance pave the way for exploitation of their application potential and offer a playground to test some of the theoretical predictions.

Journal of Materials Science: Materials in Electronics, 2022

In the present work, Li-rich layered Li(Li0.25Co0.37Mn0.38)O2 (LiCMO) material is prepared using ... more In the present work, Li-rich layered Li(Li0.25Co0.37Mn0.38)O2 (LiCMO) material is prepared using sol–gel technique. The effect of calcination temperature on the structural and morphological characteristics of LiCMO is studied. The electrochemical performance of layered LiCMO/graphite (Cell 1) and LiCMO/Li (Cell 2) has been investigated. The charge transfer resistance (Rct), lithium diffusion coefficients, and discharging capacity are found to be 16,242 Ω, 3.89 × 10–11 S−1 cm2, and 5.26 mAhg−1 and 16 Ω, 20.78 × 10–8 S−1 cm2, and 323 mAhg−1 for Cells 1 and 2, respectively. The presence of efficient lithium-ion transfer tendency and minimal kinetic barrier for lithium diffusion results in enhanced electrochemical properties of Cell 2. Appreciable results for (LiCMO/Li) coin cell make it a unique combination of LiCMO as cathode with Li as anode for the high energy density lithium-ion battery.

Springer Proceedings in Materials, 2021

Journal of Physics and Chemistry of Solids, 2022

Abstract The ferromagnetic and ferroelectric laminated structure has been utilized to study the m... more Abstract The ferromagnetic and ferroelectric laminated structure has been utilized to study the magnetoelectric (ME) effect, which holds great potential to fabricate micro-electro-mechanical devices with a high figure of merit. Designed a laminated heterostructure using ribbons of Metglas (Fe–Co–Si–B alloy) having high magnetic permeability and lead-free piezoelectric composites of 0.92(Na0.5Bi0.5)TiO3-0.08BaTiO3 (NBT-BT) to generate the significant magnitude of direct ME voltage. The displacement-voltage measurements of NBT-BT yield a high response showing the nature of the piezoelectricity effect. The strength of ME coupling is determined from the ME voltage coefficient (αME), ME measurements have been carried out in the range of 0–6 kHz frequencies. The magnitude of the direct ME effect was found about 45–50 mV/Oe.cm over a low magnetic field of less than ±8 kOe. The real-time ME effect produced nearly 274.5 and 280.2 mV of ME voltages for the applied field of 200 and 300 Oe, respectively. It shows that the trilayer composite structure may be used as weak magnetic field sensors and energy harvesters.

Proceedings IMCS 2012, 2012

Gas sensor structure based on rf sputtered SnO 2 thin film is found to be highly sensitive (1.4x1... more Gas sensor structure based on rf sputtered SnO 2 thin film is found to be highly sensitive (1.4x10 4) towards 100 ppm NO 2 gas, but with slow response (~4min.) and recovery (~33min.) times. To improve the response and recovery speeds of the sensor, different catalysts (WO 3 , TeO 2 , Al 2 O 3 , NiO, CuO and In 2 O 3) in the form of nanoclusters have been deposited over SnO 2 surface and their effect towards sensing response characteristics of NO 2 gas has been studied. Amongst all the catalysts WO 3 nanoclusters are found to be yielding a high response (5.1x10 4) for low concentration of NO 2 gas at a low operating temperature of 100 o C with a fast response and recovery times of 67sec and 17 min respectively.

Proceedings IMCS 2012, 2012

Ammonia sensing response characteristics of the Surface Acoustic Wave (SAW) sensors having differ... more Ammonia sensing response characteristics of the Surface Acoustic Wave (SAW) sensors having different oxide thin films (ZnO, TeO 2 , SnO 2 and TiO 2) deposited by RF sputtering technique under the optimized parameters as sensing layer have been studied. SAW sensor with ZnO sensing layer is found to be exhibiting the maximum response towards liquor ammonia as compared to other oxides. The SAW sensor structure showed a peculiar bidirectional shift (increase or decrease) in frequency on exposure to liquor ammonia vapors, while other VOCs (volatile organic compounds) and gases in the presence and absence of water vapors showed poor response indicating the excellent selectivity of the prepared sensors towards ammonia. Further interaction of liquor ammonia is a one step process involving adsorption of ammonia and water vapors simultaneously.

Journal of Alloys and Compounds, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

IEEE Transactions on Electron Devices, 2018

In this paper, lamb wave acoustic (LWA) devices based on ZnO/Si plate of 30-µm thickness have bee... more In this paper, lamb wave acoustic (LWA) devices based on ZnO/Si plate of 30-µm thickness have been fabricated. Devices with four different designs having acoustic wavelengths of 20, 40, 60, and 80 µm have been fabricated to study its effect on the acoustic velocity for both the lowest order antisymmetric (A 0) and symmetric (S 0) modes. The variation in effective phase difference in all the fabricated LWA devices is studied. An optimum device design is identified with appropriate distance between centers of the input and output IDTs to obtain a phase difference of 180°in antisymmetric and symmetric modes. The obtained phase difference of 180°is very critical in fabricating an oscillator for realization of wireless sensor devices. LWA devices offer high sensitivity to mass loading and thus hold tremendous potential for chemical sensing applications.

Composites Science and Technology, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Process Biochemistry, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Optics & Laser Technology, 2020

Abstract Present article demonstrates the enhanced dynamically tuneable EO modulation characteris... more Abstract Present article demonstrates the enhanced dynamically tuneable EO modulation characteristics in ferroelectric Strontium Barium Niobate S B N , S r 0.6 B a 0.4 N b 2 O 6 thin film modulator based on waveguide coupled surface plasmon resonance. The alternating modulating signals having broad frequency range (1 kHz to 10 MHz) with varying amplitude ( 40 k V / c m to 400 k V / c m ) was applied to estimate the resonance frequency (~1 MHz) using differential modulated intensity interrogation signal. A high value of EO coefficient r = 310 p m / V leading to Modulation index of 56% was achieved with sensitivity of about 0.33 at resonance possessing a characteristics length of 54.64 μm. These waveguide modes coupled with the plasmon modes paves a way for development of EO modulators utilizing materials with high losses. Therefore, a thin film based WCSPR-EO modulator with compact footprint, low operation voltage, broad operation spectrum and faster speed of modulation was fabricated which paves the way for on-chip optical communications.

Materials Science in Semiconductor Processing, 2020

The ferroelectric photovoltaic response characteristics of Lead Zirconate Titanate (PZT) thin fil... more The ferroelectric photovoltaic response characteristics of Lead Zirconate Titanate (PZT) thin film in metal-ferroelectric-metal (MFM) configuration is studied under 33 mode upon exposure to UV radiations. PZT thin films of 180 nm are prepared on inter-digital electrodes patterned silicon substrate (with silicon dioxide as insulating layer) using chemical solution deposition (CSD) technique followed by rapid thermal annealing. PZT thin films are found to be in single phase and possess high electrical polarization (50μC/cm 2). Significant increase in photocurrent and large value of open circuit voltage (1.0 V) is observed for the prepared ferroelectric photovoltaic film under UV illumination.

RSC Advances, 2019

Acrylonitrile-butadiene-styrene (ABS) composites were prepared by dry mixing equal-quantity (20 w... more Acrylonitrile-butadiene-styrene (ABS) composites were prepared by dry mixing equal-quantity (20 wt%) charcoals treated at different temperatures followed by hot compression.

Applied Physics B, 2019

The present work discusses about the modulation of input laser signal using electro-optic (EO) ef... more The present work discusses about the modulation of input laser signal using electro-optic (EO) effect in lithium niobate (LN) crystal. EO properties of LN crystal have been studied using Senarmont compensation method. Further, aiming towards the applicability of this technique in thin films, an optical waveguide has been fabricated in proton-exchanged LN (PE-LN) using prism coupling technique. Dynamic variation of the EO coefficient of PE-LN has been studied utilizing an optical waveguide with Senarmont compensation method.

Integrated Ferroelectrics, 2018

In the present work efforts have been made to develop microheater integrated gas sensors with low... more In the present work efforts have been made to develop microheater integrated gas sensors with low power consumption. The design and simulation of a single-cell microheater is carried out using ANSYS. Low power consumption (<35 mW) platinum micro-heater has been fabricated using bulk micromachining technique on silicon dioxide membrane (1.5 lm thin), which provided improved thermal isolation of the active area of 250 Â 250 lm 2. The micro-heater has achieved a maximum temperature of 950Catanapplieddcvoltageof2.5V.Fabricatedmircro−heaterhasbeenintegratedwithSnO2basedgassensorsfortheefficientdetectionofH2andNO2gases.Thedevelopedsensorswerefoundtoyieldthemaximumsensingresponseof950 C at an applied dc voltage of 2.5 V. Fabricated mircro-heater has been integrated with SnO 2 based gas sensors for the efficient detection of H 2 and NO 2 gases. The developed sensors were found to yield the maximum sensing response of 950Catanapplieddcvoltageof2.5V.Fabricatedmircro−heaterhasbeenintegratedwithSnO2basedgassensorsfortheefficientdetectionofH2andNO2gases.Thedevelopedsensorswerefoundtoyieldthemaximumsensingresponseof184 and $2.1 with low power consumption of 29.18 and 34.53 mW towards the detection of 1 ppm of NO 2 gas and 500 ppm of H 2 gas, respectively.

Microsystem Technologies, 2019

An effort has been made to develop a micro-cantilever using MEMS technology for the realization o... more An effort has been made to develop a micro-cantilever using MEMS technology for the realization of piezoelectric energy harvester. For the fabrication of micro-cantilever, a membrane of SiO 2 of thickness 1.8 lm has been integrated with piezoelectric PZT thin film and gold inter digital transducers (IDTs). MEMS based micro-cantilever with three different dimensions having cantilever lengths of 200 lm, 300 lm and 400 lm have been designed and fabricated for the realization of energy harvesters. The actuating frequency has been found to be varying with length of cantilever. The experimentally observed resonating frequencies of all prepared piezoelectric cantilevers have been validated with the theoretical simulations carried out using COMSOL multiphysics software.

Ceramics International, 2019

In this work, group II-VI metal oxide thin films of cadmium zinc oxide (Cd x Zn 1-x O), have been... more In this work, group II-VI metal oxide thin films of cadmium zinc oxide (Cd x Zn 1-x O), have been deposited using pulsed laser deposition (PLD) growth technique in an oxygen-deficient environment. The effect of cadmium content on structural, optical and electrical properties of the prepared Cd x Zn 1-x O film samples has been delineated by way of varying CdO composition in ceramic target samples. All film samples grown at substrate temperatures of 200-500 °C are revealed to have single phase wurtzite structure with a preferential orientation along (002) plane. By slightly incrementing the substrate temperature from 250 °C to 300 °C in the PLD chamber, the growth process has been further mapped out to investigate changes in said properties. XRD observations are further confirmed by Raman studies, which revealed E 2 (low), E 2 (high) and A 1 (LO) modes for all samples. Enhancement in Cd-content is found to promote the degree of crystallinity in film samples, as suggested by atomic force microscopy images. The optical band gap is estimated at 3.26, 3.16 and 3.12 eV, respectively for increasing atomic cadmium concentration in Cd x Zn 1-x O film samples deposited at 250 °C. Importantly, low resistivity films with resistivities in the order of 10-2-10-3 Ω-cm were obtained, while electron mobility showed an increasing trend with respect to the presence of cadmium content in films. PL measurements were conducted in order to unravel the origin of n-type conductivity in Cd x Zn 1-x O films. This study brings to focus growth aspects of the Cd x Zn 1-x O material system required for the development of thin film heterostructures for optoelectronic applications.

Ceramics International, 2018

Effect of non-magnetic Al 3+ doping on structural, optical, electrical, dielectric and magnetic p... more Effect of non-magnetic Al 3+ doping on structural, optical, electrical, dielectric and magnetic properties of BiFeO 3 ceramics, Ceramics International,

Sensors and Actuators B: Chemical, 2017

Highlights  CO gas sensing response studies of the rf magnetron sputtered ZnO thin films have be... more Highlights  CO gas sensing response studies of the rf magnetron sputtered ZnO thin films have been performed using SPR.  The effect of deposition temperature on the structural, surface morphological, and gas sensing properties of ZnO thin film have been studied.  The developed sensor shows a quick response (1 s) and high sensitivity (0.091 /ppm) towards CO gas.

Nanotechnology, Jan 20, 2017

Present work is focused on the growth and modification of the columnar nanostructures of SnO2 usi... more Present work is focused on the growth and modification of the columnar nanostructures of SnO2 using Glancing Angle Deposition (GLAD) assisted rf sputtering technique for low temperature detection of carbon monoxide (CO) gas. GLAD angle and deposition pressure have been optimized to tailor the grow of columnar nanostructures of SnO2, which exhibited enhanced gas sensing response of 1.49×102 towards 500 ppm of CO gas at a comparatively lower operating temperature of 110°C. The enhanced sensing response at low operating temperature is related to the growth of nanoporous columnar structures of SnO2 thin film under GLAD configuration which results in an enhanced interaction of target CO gas molecules with the large surface area of sensing SnO2 thin film. The origin of sensing mechanism supporting the observed response characteristics towards CO gas has been identified and discussed in detail.