Qualification: 
MSc
lakshmi_mohan@cb.amrita.edu

Lakshmi Mohan currently serves as Assistant Professor in Physics, Department of Sciences, School of Engineering, Coimbatore Campus. Her areas of research include Nonlinear Optics. She has also qualified SLET.

Joined Department of Sciences, Amrita Vishwa Vidyapeetham, Ettimadai Campus in 2008. Prior to that worked at Amrita Vishwa Vidyapeetham, Amritapuri campus for 3 years. Have guided several UG and PG projects for BSc and MSc Students. Undergoing doctoral research inmaterial physics from Bharathiar University

Affiliation(s):

  • Assistant Professor (Sr. G), Department of Sciences, Amrita Vishwa Vidyapeetham

Qualification

  • 2004: Masters (M.Sc)
    Catholicate College, Mahatma Gandhi University, Kerala
  • 2002: Bachelors (B.Sc)
    Assumption College, Mahatma Gandhi University, Kerala

Research Interest

  • Area of Interest
    • Nanomaterials: Synthesis of nanomaterials using simple synthesis techniques to find application in energy and environmental application
    • Functional materials: Synthesis and modification of properties of ternary metal oxide functional materials for photodiode and supercapacitor application
    • Metal oxide nanoparticles, nano synthesis, functional materials, Photocatalysis, Photodiode

Teaching

  • UG Theory:
    • Engineering PhysicsA: Basic Physics for Circuit branches
    • Engineering Physics B: Basic Physics for Non-Circuit branches
    • Mechanics and Properties of matter
    • Advanced Computer programming: Introduction to Python
    • Thermal Physics
    • Nonlinear Optics
    • Concepts of Nanophysics and Nanotechnology
    • Computational Physics
    • Physics of Semiconductor devise
    • Laser Physics and its Applications
  • PG/Ph.D Theory
    • Advanced Computational Physics
  • UG Labs
    • Advanced Computer programming: Introduction to Python
    • Mechanics and properties of Matter
    • Basic electronics
    • Basic Physics lab of Engineering courses
  • PG Labs
    • Advanced electronics

Publications

Publication Type: Journal Article

Year of Publication Title

2020

A. V, Lakshmi Mohan, P, K., and Saravanakumar, S., “Grain boundary effect on the structural, optical and electrical properties of Sol gel synthesized Fe doped SnO2 Nanoparticles”, Chinese Physics B, 2020.[Abstract]


Tin oxide (SnO2) and Iron doped tin oxide (Sn1-xFexO2 (x=0.05, 0.10wt%)) nanoparticles were synthesized by simple sol-gel method. The structural characterization performed using X-ray Diffraction (XRD) confirmed the tetragonal rutile phase of the nanoparticle. The variation in lattice parameters and relative intensity with Fe doping validated the incorporation of Iron into the lattice. The compressive strain present in lattice estimated using peak profile analysis using Williamson-Hall plot also exhibited influence of grain boundary formation in the lattice. The radiative recombination and quenching observed in optical characterization done using Photoluminescence spectra (PL) and shift in the band gap estimated from UV-Visible Diffused Reflectance Spectroscopy corroborated the grain boundary influence. Raman spectroscopy and the morphological analysis done using a Field emission scanning electron microscope (FESEM) also reinforced the formation of grain boundaries. The compositional analysis done using Energy Dispersive X Ray Spectroscopy (EDAX) confirmed Fe in SnO2 lattice. The conductivity studies performed exhibited an increase of impendence with increased doping concentration and a decrease in the loss factor at high frequencies with increased doping concentration which makes it a potential candidate for device applications

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2020

Lakshmi Mohan, Sisupalan, N., Ponnusamy, K., and Sadagopalan, S., “One Step Synthesis and Characterization of ZnO–ZnSe Heterostructures by Chemical Precipitation and Its Solar Photocatalytic Activity”, vol. 30, no. 7, pp. 2626 - 2632, 2020.[Abstract]


ZnO–ZnSe heterostructures were successfully synthesized by single step chemical precipitation method at room temperature. The obtained composite structures were systematically characterized for structural, morphological, optical, and vibrational properties using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), High-resolution transmission electron microscopy (HRTEM), UV–Vis DRS, photoluminescence spectroscopy (PL), and Fourier-transform Raman spectroscopy (FT-Raman). XRD patterns of the synthesized samples exhibit peaks corresponding to wurtzite ZnO and ZnSe structures which primarily confirmed the formation of single phase heterostructures. ZnO microspheres grown over the surface of ZnSe nano cauliflower clusters obtained from the FESEM images confirmed the formation of ZnO–ZnSe heterostructures. A sharp peak around 290 nm in UV–Vis DRS absorption spectra corresponds to ZnSeO3 and a wide weak absorbance is observed in the visible region (ranging from 370 to 663 nm) corresponding to the nanocomposite structure. In the Raman spectra, the surface phonon mode which is the characteristic feature of the ZnO–ZnSe heterostructures is observed at 237 cm−1. Based on the characterization results, the photocatalytic properties of ZnO–ZnSe nanoparticles were evaluated for the degradation of methylene blue (MB) and was found to exhibit solar photocatalytic property.

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2020

N. A, P, K., Lakshmi Mohan, S, S., R, M., and J, C., “Jet nebuliser spray pyrolysed indium oxide and nickel doped indium oxide thin films for photodiode application”, Optik, vol. 202, p. 163701, 2020.[Abstract]


Indium oxide thin films at different substrate temperatures (250−450 °C) and nickel doped indium oxide films with various doping concentration of 10 and 15 wt% were coated (at 400 °C) using jet nebulizer spray pyrolysis technique confirmed the cubic phase of the films from X-ray diffraction analysis. The micro-strain effects were also verified by Williamson-Hall method. Field emission scanning electron microscopy (FE-SEM) confirmed temperature dependence in the formation of octahedron layered geometry. The influence of temperature on surface irregularity and its effect on band gap shift confirmed using optical characterization was attributed to Burstein-Moss shift. The influence on doping was reinforced with the emission peak shift of photoluminescence spectra in ultra violet, violet and blue regions (394, 421 and 467 nm). Based on confirmations from these characterizations, n-In2O3/p-Si junction diodes were fabricated for as prepared In2O3 and 10 and 15 wt% concentrations nickel doped In2O3 at 400 °C. P-N junction diodes fabricated and analyzed showed high sensitivity for 15 wt% nickel doped indium oxide under illumination condition. On account of this 15 wt% nickel doped junction diode is a good candidate for optoelectronic devices.

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2020

Lakshmi Mohan and Dr. Vivek Menon, “Modelling large scale camera networks for identification and tracking: an abstract framework”, IET Computer Vision, vol. 14, pp. 426-433, 2020.[Abstract]


In this study, the authors discuss a novel approach for multi-camera-based unobtrusive identification and tracking of occupants in wide-area, multi-building scenarios. Considering the scalability issues in adopting a centralised approach to monitor wide-area scenarios, they proposed a distributed approach to occupant identification and tracking. The key technical idea underlying their approach is to abstract a wide-area indoor surveillance environment using a distributed state transition system (DSTS) model, which in turn is composed of independent building-specific state transition systems, coordinating and collaborating with each other. This study presents the details of their DSTS model and examines the temporal ordering of recognition events within the DSTS for ensuring accurate state information and responses to spatio–temporal queries. They also provide an experimental evaluation of the performance of their model using precision-recall metrics. Their conclusion is that the DSTS model serves as an efficient mechanism for tracking occupants in wide-area, multi-building scenarios monitored by camera networks.

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2018

N. M. Rohith, Kathirvel, P., Saravanakumar, S., and Lakshmi Mohan, “Influence of Ag doping on the structural, optical, morphological and conductivity characteristics of ZnO nanorods”, Optik, vol. 172, pp. 940-952, 2018.[Abstract]


This article reports systematic study of Silver doping on ZnO nanorods synthesized by a simple chemical precipitation method. The prepared samples were characterized for structural, morphological, constitutional, optical and dielectric analysis. The XRD spectra confirmed the hexagonal wurtzite phase of the synthesized samples. The lattice parameter variation revealed the formation of nano inclusions at the boundaries. This was reaffirmed using the peak profile analyses of all samples using W-H analysis. The morphological and compositional analysis was done using SEM & EDAX. The quenching of visible (green) observed from PL spectra along with doping is not being much reported is also been studied. FTIR data confirmed the formation of Ag doped ZnO nanorods by chemical composition analysis. The dielectric and ac conductivity modification studies as a function of frequency and composition was performed using LCR meter which also showed a clear influence of Ag doping. © 2018 Elsevier GmbH

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2012

, Dr. Soman K. P., Kurian, A. P., Kartha, M. M., and Lakshmi Mohan, “Modified Wavelet image fusion based on OSVD”, IJERT, 2012.

2012

A. P. Kurian, Dr. Soman K. P., Kartha, M. M., Lakshmi Mohan, and R, B. S., “Performance Evaluation of Modified SVD based Image fusion”, IJCA, 2012.

Publication Type: Conference Proceedings

Year of Publication Title

2013

S. R. Mohan, S. Kumar, S., and Lakshmi Mohan, “Sudy of phase transformation in calcium oxalate nanoparticles on annealing”, National Conference on Recent Advances in Surface Science (RASS 2013). Gandhigram Rural Institute - Deemed University, Gandhigram - 624 302, Dindigul, Tamil Nadu, 2013.

Faculty Research Interest: