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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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