A5016450041- Graphene research and applications
- 2D Materials and Applications
- Carbon Nanotubes in Composites
- Thermal properties of materials
- ZnO doping and properties
- Quantum and electron transport phenomena
- Transition Metal Oxide Nanomaterials
- Recycling and utilization of industrial and municipal waste in materials production
- Physics of Superconductivity and Magnetism
- Diamond and Carbon-based Materials Research
- Gas Sensing Nanomaterials and Sensors
- Coastal and Marine Dynamics
- Ga2O3 and related materials
- Semiconductor materials and devices
- Coastal wetland ecosystem dynamics
- Land Use and Ecosystem Services
- Organic and Molecular Conductors Research
- Remote Sensing in Agriculture
- Glass properties and applications
- Radio Frequency Integrated Circuit Design
- Coastal and Marine Management
- Thin-Film Transistor Technologies
- Geophysics and Gravity Measurements
- Building materials and conservation
- Pigment Synthesis and Properties
Advanced Centre for Treatment, Research and Education in Cancer
2024
University of California, Riverside
2008-2024
Jadavpur University
2012-2024
California NanoSystems Institute
2024
Institute of Management Technology
2023-2024
Tata Memorial Hospital
2024
University of California, Los Angeles
2023-2024
California State University, San Bernardino
2023
Asian Institute of Technology
2022
Central Glass and Ceramic Research Institute
1994-2019
The authors reported on investigation of the thermal conductivity graphene suspended across trenches in Si∕SiO2 wafer. measurements were performed using a noncontact technique based micro-Raman spectroscopy. amount power dissipated and corresponding temperature rise determined from spectral position integrated intensity graphene’s G mode. extremely high range ∼3080–5150W∕mK phonon mean free path ∼775nm near room extracted for set flakes. obtained results suggest applications as management...
The authors proposed a simple model for the lattice thermal conductivity of graphene in framework Klemens approximation. Gruneisen parameters were introduced separately longitudinal and transverse phonon branches through averaging over modes obtained from first-principles. calculations show that Umklapp-limited grows with increasing linear dimensions flakes can exceed basal planes bulk graphite when flake size is on order few micrometers. results are agreement experimental data reflect...
We review the results of our experimental investigation heat conduction in suspended graphene and offer a theoretical interpretation its extremely high thermal conductivity. The direct measurements conductivity were performed using non-contact optical technique special calibration procedure with bulk graphite. measured values range ∼3000–5300 W mK−1 near room temperature depended on lateral dimensions flakes. explain enhanced as compared to that graphite basal planes by two-dimensional...
The Sundarbans mangrove ecosystem, located in India and Bangladesh, is recognized as a global priority for biodiversity conservation an important provider of ecosystem services such numerous goods protection against storm surges. With mean sea-level rise projected up to 0.98 m or greater by 2100 relative the baseline period (1985–2005), – elevation presently approximately 2 above under threat from inundation subsequent wetland loss; however magnitude loss remains unclear. We used remote...
Shoreline prediction models have the capability of integrating geoinformatics within them. The present study is conducted on 142 km-long coastline Puri district, India. It aims to analyze change in due erosion/accretion and provide best estimate future shoreline positions based past shorelines. A simple mathematical model, End Point Rate (EPR), has been used calculate rate its positions, empirical observations. erosional/accretional scenario also analysed by delineating from Landsat...
The magnetic properties in two-dimensional van der Waals materials depend sensitively on structure. CrI3, as an example, has been recently demonstrated to exhibit distinct depending the layer thickness and stacking order. Bulk CrI3 is ferromagnetic (FM) with a Curie temperature of 61 K rhombohedral stacking, whereas few-layer layered antiferromagnetic (AFM) phase lower ordering 45 monoclinic stacking. In this work, we use cryogenic force microscopy investigate flakes intermediate range...
We report results of investigation the phonon and thermal properties exfoliated films layered single crystals antiferromagnetic FePS3 MnPS3 semiconductors. Raman spectroscopy was conducted using three different excitation lasers with wavelengths 325 nm (UV), 488 (blue), 633 (red). UV-Raman reveals spectral features which are not detectable via visible light scattering. The conductivity thin measured by two techniques: steady-state optothermal transient time-resolved magneto-optical Kerr...
Abstract Polymer composite films containing fillers comprising quasi‐1D van der Waals materials, specifically transition metal trichalcogenides with 1D structural motifs that enable their exfoliation into bundles of atomic threads, are reported. These nanostructures characterized by extremely large aspect ratios up to ≈ 10 6 . The polymer composites low loadings TaSe 3 ( < vol%) reveal excellent electromagnetic interference shielding in the X‐band GHz and high frequency sub‐THz ranges,...
Abstract We report the results of polarization‐dependent Raman spectroscopy phonon states in single‐crystalline quasi‐one‐dimensional NbTe 4 and TaTe van der Waals materials. The measurements were conducted wide temperature range from 80 to 560 K. Our show that although both materials have identical crystal structures symmetries, there is a drastic difference intensity their spectra. While exhibits well‐defined peaks through examined wavenumber ranges, reveals extremely weak signatures....
Abstract We review the results of our experimental and theoretical investigation heat conduction in suspended graphene layers. Through direct measurements using a noncontact optical technique, we established that thermal conductivity flakes is extremely high, exceeds diamond carbon nanotubes. By invoking Klemens' model, explained physical mechanisms behind such unusual two-dimensional Our detailed theory, which includes phonon-mode dependent Gruneisen parameter takes into account phonon...
Abstract Low‐frequency current fluctuations, i.e., electronic noise, in quasi‐1D (TaSe 4 ) 2 I Weyl semimetal nanoribbons are discussed. It is found that the noise spectral density of 1/ f type and scales with square current, S ~ ( frequency). The increases by almost an order magnitude develops Lorentzian features near temperature T ≈ 225 K. These changes attributed to charge‐density‐wave phase transition even though maximum deviates from reported Peierls bulk crystals. level, normalized...
We report on the temperature evolution of polarization-dependent Raman spectrum exfoliated MoI$_3$, a van der Waals material with "true one-dimensional" crystal structure that can be to individual atomic chains. The several features reveals anomalous behavior suggesting phase transition magnetic origin. Theoretical considerations indicate MoI$_3$ is an easy-plane antiferromagnet alternating spins along dimerized chains and inter-chain helical spin ordering. calculated frequencies phonons...
The authors report on the experimental investigation of thermal conductivity nitrogenated ultrananocrystalline diamond (UNCD) films silicon. For better accuracy, was measured by using two different approaches: 3ω method and transient “hot disk” technique. temperature dependence UNCD compared to that undoped microcrystalline (MCD) It shown films, which is substantially from for MCD can be adequately described phonon-hopping model. room-temperature 8.6–16.6 W/m K decreases with addition...
The authors report on a new method for the synthesis of graphene, mono-layer carbon atoms arranged in honey comb lattice, and assessment properties obtained graphene layers using micro-Raman characterisation. Graphene was produced by high pressure–high temperature (HPHT) growth process from natural graphitic source material utilising molten Fe–Ni catalysts dissolution carbon. resulting large-area flakes were transferred to silicon–silicon oxide substrates spectroscopic scanning electron...
The authors report results of investigation thermal conductivity nanocrystalline yttria-stabilized zirconia. optically transparent pore-free bulk samples were prepared via the spark plasma sintering process to ensure homogeneity. Thermal K was measured by two different techniques. It found that nanostructured zirconia is an excellent insulator with room-temperature K∼1.7–2.0 W/m K. also shown “phonon-hopping” model can accurately describe specifics dependence on temperature and grain size....
An intrinsic antiferromagnetic topological insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ arises when intercalating a Mn-Te bilayer chain in insulator, ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$. We present observations on the inter- and intralayer phonon modes of generalized $\mathrm{Mn}\phantom{\rule{0.28em}{0ex}}{\mathrm{Bi}}_{2n}{\mathrm{Te}}_{3n+1}(n=1,2,3,4)$ family using cryogenic low-frequency Raman spectroscopy with various polarization configurations. Two peaks at 66...
The total blue carbon stock of the Bangladesh Sundarban mangroves was evaluated and probable future status after a century predicted based on recent trend changes in last 30 years implementing hybrid model Markov Chain Cellular automata. At present 36.24 Tg C 54.95 are stored above-ground below-ground compartments respectively resulting 91.19 C. According to prediction 15.88 would be lost from this region by year 2115. low saline species composition classes dominated mainly Heritiera spp....
Abstract Low‐frequency current fluctuations, i.e., noise, in the quasi‐2D van der Waals antiferromagnetic semiconductor FePS 3 with electronic bandgap of 1.5 eV is investigated. The electrical and noise characteristics p ‐type, highly resistive, thin films are measured at different temperatures. spectral density 1/ f ‐type over most examined temperature range but reveals well‐defined Lorentzian bulges, increases strongly near Néel T N = 118 K ( frequency). Intriguingly, attains its minimum ≈...
We report results of an investigation low-frequency excess noise in high-current diamond diodes. It was found that the electronic diodes is dominated by generation - recombination noise, which reveals itself either as Lorentzian spectral features or a 1/f spectrum (f frequency). The bulges are characteristic for with lower turn-on voltages. density dependence on forward current, I, three distinctive regions all examined devices it scales I^2 at low (I<10 uA) and high (I>10 mA)...
We report on the low-frequency electronic noise in β-(AlxGa1−x)2O3 Schottky barrier diodes. The spectral density reveals 1/f dependence, characteristic of flicker noise, with superimposed Lorentzian bulges at intermediate current levels (f is frequency). normalized such diodes was determined to be order 10−12 cm2/Hz = 10 Hz) 1 A/cm2 density. At regime, we observed random telegraph signal correlated appearance spectrum. attributed defects near barrier. can affect local electric field and...
Abstract Temperature dependence of the low‐frequency electronic noise in NiO x /β‐Ga 2 O 3 p – n heterojunction diodes is reported. The spectral density 1 / f ‐type near room temperature but shows signatures Lorentzian components at elevated temperatures and higher current levels ( frequency). It observed that there an intriguing non‐monotonic on T = 380 K. Raman spectroscopy device structure suggests material changes, which results reduced above this temperature. normalized such determined...