Harnessing the Ion Bombardment process to create novel nanostructures


Cover picture courtesy: Ms. Nandini Bhosale, IDC

The rapidly evolving field of micro- and nano-fabrication is the meeting ground of physics, chemistry, biology, medicine, and engineering.

Conventional lithography techniques are widely used to fabricate microstructures commercially. However, such techniques have limitations at the nano level. Research in areas related to nanofabrication is therefore crucial in order to develop and improve novel manufacturing techniques.

This is where Vivek Garg, a research scholar with the IITB-Monash Research Academy, is hoping to make a significant contribution.

“My research is based on Focused Ion Beam (FIB) process for nanofabrication and its application in creating novel nanostructures,” explains Vivek. “The aim is to model ion-material interactions followed by rapid computation ion beam-based material removal (milling or etching), in order to create 2D/3D structures at both micro- and nano-scale for diverse applications like anti-reflection, colour filters, and sensors, to name a few.”

The Academy is a collaboration between India and Australia that endeavours to strengthen scientific relationships between the two countries. Graduate research scholars like Vivek study for a dually-badged PhD from both IIT Bombay and Monash University, spending time at both institutions to enrich their research experience.

Says Vivek, “FIB is a promising technique due to its capability range and diverse applications”.

For instance, it can be used for:

  • milling, thus making it suitable for micro- / nano-machining,
  • deposition, allowing for additive nanomanufacturing applications, and
  • imaging, which makes it even more powerful for microscopy analysis and materials applications.

Vivek plans to develop a reliable modelling methodology to predict optimized FIB process parameters for milling, which is expected to lead to robust and accurate 2D/3D structures at the micro- / nano-scale. He is currently working on ion induced, in-situ controlled manipulation of nanostructures and investigation through molecular dynamics simulations, in order to arrive at a feasible methodology. This work will be critical for 3D nanofabrication with promising nanoscale-controlled manipulation, strain engineering of nanostructures, opening new avenues in the diverse field of ion beams and applications beyond material science for realization of future nanoscale devices.

Optimization of Focused Ion Beam (FIB) milling process: Simulation results for a spherical profile obtained from optimization algorithm at a beam current of 20 pA and pixel size of 3 nm (a) Designed spherical profile, (b) Simulated spherical profile, (c) Error between the designed and simulated profile [1]

Rapid prototyping of subwavelength silicon nanostructures for light trapping and antireflection Properties (a) Scanning electron microscopic (SEM) image of fabricated designed Si Gaussian pillar nanostructures, (b) Antireflection properties exhibited through fabricated pillars and comparison with simulation results, (c) Optical absorption per unit volume exhibiting light trapping [2]

Structural colour printing with FIB: (a) Direct fabrication of subwavelength nanostructures for multicolour generation, (b) A wide colour palette shown with optical microscopic images of fabricated colour filters, (c) Nanoscale structural color printing: few examples, such as butterfly, Kangaroo, letters, shown via SEM image and including corresponding optical microscopic image showing generation of unique structural colours [3], [4]

Microscopic Gardening: Tiny Blossoms of Silicon
The image shows scanning electron micrograph of silicon nanoflowers realized with focused ion beam in conjunction with wet chemical etching methods. The bulk structuration of Si substrate, based on the ion implantation design and area, allows fabrication of exotic functional and 3D micro/nanostructures on Si substrate exhibiting unique optical properties for applications in nanophotonics and physical sciences (Image scale bar 400 nm)

Prof Murali Sastry, CEO of the IITB-Monash Research Academy and a leading nanomaterial scientist says, “Nanofabrication is an art. Future applications require materials with improved electronic, magnetic, optical, and mechanical properties. Many of these properties are defined by the structure and composition in the size range below 100 nm. It is most important to maintain the material integrity and composition as we move towards the nano-scale, which is what makes Vivek’s project so challenging.”

Oftentimes, it pays to think small when we need to think big!

Research scholar: Vivek Garg, IITB-Monash Research Academy
Project title: Focused Ion Beam (FIB) Fabrication of Novel 2D/3D Nanoscale Structures: Process Modeling and Applications
Supervisors: Prof. Rakesh G. Mote, Prof. Jing Fu
Contact details: vivekgarg@iitb.ac.in, vivek.garg@monash.edu

 

[1] V. Garg, R. G. Mote, and J. Fu, “Focused Ion Beam Fabrication: Process Development and Optimization Strategy for Optical Applications,” in Precision Product-Process Design and Optimization, Springer, Singapore, 2018, pp. 189–209.
[2] V. Garg, R. G. Mote, and J. Fu, “FIB fabrication of highly ordered vertical Gaussian pillar nanostructures on silicon,” in 2017 IEEE 17th International Conference on Nanotechnology (IEEE-NANO), 2017, pp. 707–712.
[3] V. Garg, R. G. Mote, and J. Fu, “Coloring with Focused Ion Beam Fabricated Nanostructures,” Microscopy and Microanalysis, vol. 24, no. S1, pp. 856–857, Aug. 2018.
[4] V. Garg, R. G. Mote, and J. Fu, “Focused Ion Beam Direct Fabrication of Subwavelength Nanostructures on Silicon for Multicolor Generation,” Advanced Materials Technologies, vol. 3, no. 8, p. 1800100, Aug. 2018.

 

Automatic Q&A Generation from Text


Asking relevant and intelligent questions has always been an integral part of human learning, as it can help assess the learner’s understanding of a piece of text. However, compiling questions manually is arduous. Automated question generation (QG) systems can help, as they have the ability to generate questions quicker and on a larger scale.

A typical scenario is evaluating students on reading comprehension, where it becomes tedious for a teacher to manually create questions, find answers to these questions, and then evaluate answer papers after the test has been administered. All these complex tasks can now be automated using an automatic question and answer generation system.

This is why research scholar Vishwajeet Kumar’s project titled, ‘Automatic Question and Answer Generation from Text’ has tremendous potential in a scenario where scientists are closely examining the efficacy of neural network-based methods in question generation from text.

“A compact Question Generation system would be able to generate meaningful, syntactically correct, semantically sound, and natural questions from text. The questions that work best are those that have supporting answers present in the text,” explains Vishwajeet, who has enrolled for a PhD programme in the IITB-Monash Research Academy,

 Early attempts at automated question generation depended heavily on a strict, limited, ad-hoc, and hand-crafted set of rules. These rules focus mainly on the syntactic structure of the text and are limited only to sentences of simple structures. Recently, the success of sequence-to-sequence learning models has opened up possibilities of looking beyond a fixed set of rules for the task of question generation.

 An automatic question generation system has applications in areas as diverse as FAQ generation, intelligent tutoring systems, and virtual assistants. Question generation can be naturally applied in the educational setting such as online courses, automated help systems, and search engines. It can also be applied in a wide variety of other domains — including chatbot systems (e.g. for customer interaction) and health care for analysing mental health.

Explaining his work so far, Vishwajeet says, “We present a system to automatically generate question and answer from text. Our system follows a two-stage process to generate question-answer pairs from the text. In the first stage, we present alternatives for encoding the span of the pivotal answer in the sentence using Pointer Networks. In the next stage, we employ sequence-to-sequence models for question generation, enhanced with rich linguistic features. Finally, global attention and answer encoding are used for generating the question most relevant to the answer.”

The IITB-Monash Research Academy is a collaboration between India and Australia that endeavours to strengthen scientific relationships between the two countries. Graduate research scholars like Vishawajeet study for a dually-badged PhD from both IIT Bombay and Monash University, spending time at both institutions to enrich their research experience.

Says Prof. Murali Sastry, CEO of the IITB-Monash Research Academy, “More and more institutions are moving from classroom teaching to online courses using platforms like MOOC, EDX, etc. For those administering such online courses, generating meaningful questions manually is a tedious task. The work of researchers like Vishwajeet shows us that asking meaningful and intelligent questions will improve the ability to answer them!”

Research scholar: Vishwajeet Kumar, IITB-Monash Research Academy

Project title: Automatic Question and Answer Generation from Text

Supervisors: Prof.Ganesh Ramakrishnan and Prof. Yuan-Fang Li

Contact details: vishwajeet@cse.iitb.ac.in

The above story was written by Mr Krishna Warrier based on inputs from the research student, his supervisors, and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.

 

 

 

 

Nanostructure fabrication inspired by sand dune ripples


What can nanotechnologists learn from ripples on sand dunes?

A lot, smiles Bhaveshkumar Kamaliya, a research scholar with the IITB-Monash Research Academy — who is convinced that if he can mimic the macro-scaled ripples or wave-patterns seen on sand dunes to a nanoscale, it will help him study interactions of ion beams with surfaces of different materials, and perhaps even create self-organized nanostructures.

Nano-scaled structures strongly improve optical, electrical, and magnetic properties of materials. This has led to the study and development of many nanostructure-based devices; however nano-structuring poses a tremendous challenge as the fabrication process for such devices is not available due to limitations of conventional photolithography and electron beam lithography techniques.

“My project has two key aspects,” explains Bhavesh, “(i) experimental investigations for the formation of nanoripples, nanodots, and other complex nanostructures by varying parameters of energetic ion beams, and (ii) molecular dynamics simulations and modelling for understanding, validating and predicting experimental outcomes.”

“The self-organized nanoripples have the potential to serve as functional nanostructures and exhibit novel structures required for photovoltaics, surface plasmons, photonics, bio-sensing, etc.,” says Bhavesh. “Controlling the topography at the nanoscale is challenging and studying the mechanism behind the phenomena could help develop new and complex materials.”

His work is likely to offer the scientific community a systematic understanding of the mechanism behind self-organized nanostructures induced by Focused Ion Beam (FIB) irradiation. It could even lead to the fabrication of an efficient photovoltaic-based energy harvesting device or surface plasmon-based bio-sensing device.

Nanorippled Germanium: (a) Scanning electron micrograph (false coloured) of nanoripples on germanium surface induced by focused ion beam irradiation, (b) mechanism of enhanced light absorption due to multiple reflections through nanoripples and (3) experimentally measured light absorption from nanorippled germanium and bare germanium surface. (Reference: B. Kamaliya, R. Mote, M. Aslam, and J. Fu, APL Materials 6, 036106 (2018); doi: 10.1063/1.5021735).

The Academy is a collaboration between India and Australia that endeavours to strengthen scientific relationships between the two countries. Graduate research scholars like Bhavesh study for a dually-badged PhD from both IIT Bombay and Monash University, spending time at both institutions to enrich their research experience.

Prof Murali Sastry, CEO of the IITB-Monash Research Academy, and a reputed nanomaterial scientist, is excited. “The Academy is an opportunity for industry in Australia and India, as well as for IIT Bombay and Monash University, to train the next generation of rich talent in India. It has the potential to be a significant research institution. Talent from the Academy should become much sought after around the globe. This project could open new avenues on controlling nanoripples orientation and high-efficiency germanium-based photovoltaic applications.”

Indeed. We hope Bhavesh’s work will cause significant ripples — both literal and metaphorical.

Research scholar: Bhaveshkumar Kamaliya, IITB-Monash Research Academy
Project title: Study of Ion Beam Interaction with Materials and Nanostructure Fabrication
Supervisors: Prof Mohammed Aslam, Prof Rakesh G. Mote and Prof Jing Fu
Contact details: rakesh.mote@iitb.ac.in, bkamaliya@gmail.com

 

The above story was written by Mr Krishna Warrier based on inputs from the research student, his supervisors, and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.

Somnath Buriuly


Somnath Buriuly
Somnath completed his B.Tech in Electrical Engineering from NIT Durgapur in the year 2013. He joined GAIL (India) Ltd as a senior engineer in the same year. Soon after, he left GAIL and started perusing his passion in Robotics through M.Tech in Control Systems Engineering from IIT Kharagpur. He completed his M.Tech in the year 2016 by submitting a thesis on interval type-2 fuzzy PI/PD controllers. He is currently working on a project titled: “Coordinated inspection of railway tracks using multiple robots” under the supervision of Prof. Leena Vachhani (IIT Bombay), Prof. Arpita Sinha (IIT Bombay), Prof. Sunita Chauhan (Monash University), and Prof. Ravi Ravitharan (Monash University). His interests include automation in robotics, table tennis, etc.
Link to student’s project: IMURA0638

Soumyajit Mojumder


Soumyajit Mojumder
Soumyajit Mojumder completed his B.Tech in Mechanical Engineering from West Bengal University of Technology in the year 2014 and M.Tech in Mechanical Engineering (specialization in Maintenance Engineering and Tribology) from Indian School of Mines, Dhanbad in the year 2016. His M.Tech thesis work is titled “Experimental study of wear for Implant materials under lubricated sliding conditions”. He has two journal papers to his credit as part of M.Tech thesis work, published in Journal of Material Science and Mechanical Engineering along with two manuscripts currently under advanced stage of revision in Journal of Industrial Lubrication and Tribology and Journal of Engineering Tribology respectively. His interest in the field of Tribology led him to apply for the Joint PhD program at IITB-Monash Research Academy. His doctoral research is broadly classified as “Effect of microstructure on rail/wheel interaction and defects”. He will be working under the guidance of Prof. Aparna Singh (IIT Bombay), Prof. Wenyi Yan (Monash University), Prof. Cong Qiu (Monash University), Prof. Peter Mutton (Monash University) during his Phd.
Link to student’s project: IMURA0648

Sagar Agnihotri


Sagar Agnihotri
I completed my B-Tech in Mechanical Engineering from Government College of Engineering, Amravati in 2011.After completing my graduation I worked with Thermax Ltd Pune in field of heat recovery units and later took admission in Heat Power Engineering (Thermal) in Visvesvaraya National Institute of Technology, Nagpur (VNIT). During M-tech, for completing a project I worked as Intern for 1 year in Thermax ltd Pune R & D Division, where I worked on a project for heat transfer enhancement using CFD tool. The exposure to the industry and academia urged me to take up PhD at IITB-Monash Research Academy. I will be working on ‘A finite-element solver for internal fluid dynamics during particle-laden droplet impact and evaporation on a solid surface’ under guidance of Prof. Rajneesh Bhardwaj (IITB), Prof. Adrian Neild and Prof. Tuncay Alan (MONASH University). Apart from studies I am very much interested in chess and cricket.

Link to student’s project: IMURA0465

Shivali Banerjee


Shivali Banerjee

I am Shivali Banerjee, currently a final year student pursuing MSc. Chemistry at the Indian Institute of Technology (IIT), Delhi, since 2014.

My journey with chemistry started from simple high school experiments which were limited to Bunsen burners, pH stripes or a few test tubes. Now that I am about to finish my masters with much more knowledge about the world of chemistry, I still feel the same excitement that I felt back then. The subject has never failed to amaze me, right from my days of high school to even today.
In 2011, I passed class 12th with 94.33 marks and was among the top 1% students of ISC (Indian School Certificate) Board. I received the prestigious INSPIRE (Innovation in Science Pursuit for Inspired Research) Scholarship. To pursue a career in basic sciences, I joined three year BSc. (Hons.) Chemistry programme at Miranda House College of University of Delhi, one of the most prestigious institutions in India for undergraduate studies and research in pure sciences.

In 2012, during my second year in BSc. Hons Chemistry course, I joined my first one year long research project “Computational Modelling of Phytoregulatory Profile of some Nanoparticles (May,2012 to May,2013) under Dr. Sushma Moitra (Principal Investigator). The project was sponsored by the University of Delhi under the Innovation Project Scheme.

I joined Prof. T Pradeep as a summer research fellow (May-July 2013) at DST Unit of Nanoscience, IIT Madras. This summer fellowship was sponsored by the Indian Academy of Sciences. During the internship I worked on synthesis and characterizing of thiol protected palladium nano-clusters. The project gave me more insight into various characterization techniques like Electrospray Ionisation Mass Spectrometry (ESI MS) , Matrix Assisted Laser Desorption/Ionisation (MALDI), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM) and High Performance Liquid Chromatography (HPLC).

I also earned a gold medal at the end of BSc. (Hons.) Chemistry course for securing highest marks in the three years of this course. I am an awardee of the URH (University Rank Holder) Fellowship sponsored by University Grants Commision. I qualified the Joint Admission test for MSc (JAM) and joined Indian Institute of Technology (IIT) Delhi for masters in 2014. I have been among the top three students in the MSc Chemistry course at IIT Delhi.

I completed my master’s thesis project under the supervision of Prof. Ashok K Ganguli, Solid State and Nanomaterial Research Lab, IIT Delhi. My research project involves synthesizing a series of nanocatalysts for hydrogen-evolution by water splitting. While working on this project, I learnt to operate powder X-Ray Diffractometer, Thermogravimetric instrument, Infrared Spectrophotometer, Electrochemical set-up of a three-electrode system, etc. I also learnt the analysis of the electrochemical data, such as LSV Curves, Cyclic Voltammograms, Tafel plots, Nyquist plots etc.

I presented a poster on my work at MNIT Jaipur(2015), Rajasthan and another at the Australia-India Strategic Research Fund Meeting(2015) held at IISER Mohali, Chandigarh, India.


Link to student’s project: IMURA0453


Shivani Agarwal


Shivani Agarwal
Shivani Agarwal completed her B.Tech. in Electronics and Communication Engineering from Engineering College Bikaner affiliated by Rajasthan Technical University in 2011. She has done her M.Tech. in Solid State Technology from Indian Institute of Space Science and Technology in 2015. During Masters she worked on Fabrication and Characterisation of Organic, Inorganic and Hybrid Resistive Random Access Memory Devices under supervision of Dr. K.B. Jinesh. Soon after the completion of M.Tech. program she joined IIT Jodhpur as Senior Research Fellow on the project “Ion Beam Synthesis and Characterisation of Gallium nitride based nanocrystals embedded in Si matrices for New Generation Photodetector and Light Emitter Application ” under Dr. Mahesh Kumar. At IITB- Monash Research Academy she is working on Project- Quantum Dot Spin Qubit in Graphene under guidance of Dr. Sudhasatta Mahapatra (IIT Bombay), Dr Bent Weber (Monash University), Dr Michael S. Fuhrer (Monash University) and Dr. Changxi Zheng (Monash University).
Link to student’s project: IMURA0622

Siddharth Gupta


Siddharth Gupta
Siddharth completed his B.E in Mechanical Engineering from BIT Durg in 2011 and his M.Tech in Engineering mechanics from IIT Delhi in 2013. He numerically investigates the behavior of liquid steel flow inside a tundish under the guidance of Prof. Anupam Dewan (IIT Delhi). He published two papers from this project. After completing Master’s Degree, he joined G D Rungta college of Engineering & Technology & gained an experience of 34 months. He would be working on a project titled: “CFD Study on Hydrodynamics of Fish like Locomotion using Level Set based Immersed Boundary Method” under the supervision of Prof. Atul Sharma (IIT Bombay), Prof. Amit Agrawal (IIT Bombay) & Prof. Kerry Hourigan (Monash University). He enjoys outdoor activities like cricket and travelling.
Link to student’s project: IMURA0413

Subramoni Hariharan


Subramoni Hariharan
Subramoni completed his Masters in Biotechnology from V G Vaze College (Mumbai University) in 2012. He later joined the Animal Biotechnology and Biochemistry department at KET’s Scientific Research Centre (SRC) as a toxicologist, where his primary responsibilities were to assess the safety and efficacy of cosmetics, API’s and therapeutic molecules from plant origin. Over the past 4 years, he has been involved in projects focused on isolation and characterization of bioactive molecules from plants, formulations and their validation through clinical trials. He has also presented his research in various national level seminars and conferences.
After clearing the GATE (AIR 60) and CSIR-LS (AIR 34), he recently joined the IITB-Monash academy as a research scholar, under the supervision of Dr. Amit Arora (IITB) and Dr. Antonio Patti (Monash University). His project revolves around the extraction of high quality protein from plant based sources.
When not in lab, subramoni loves to catch up on his reading and playing cricket, and idly enjoying nature.
Link to student’s project: IMURA0666 (6)