Nanosciences @Indian Institute of Technology Kanpur

Nano-Science & Technology InitiativeDepartment of Science and Technology, India

Ashutosh SharmaDepartment of Chemical Engineering

DST Unit on Nanosciences @ IITK

Mesoscale Structures, Patterning and Properties with Emphasis on Soft Materials and Thin Films

A state-of-the-art facility and resources for soft matter nanoscience and nanotechnology.

Explore new techniques of nano-fabrication based on a creative combination of “top-down” including soft lithography, self-assembly and self-organization.

Projects related to nano-scale understanding, fabrication and use of soft materials in coatings, NEMS, functional interfaces and bulk-nano

Journey of the last two years!

Nano-Sciences at IITK: A Mega-Passion…….

Self-assembly

Micro- and Nano Fabtructure Property Behavior

Lithographies, Beams…

op-own

Bottom-up

Self-organization

Highly Multidisciplinary AND Interdisciplinary TeamCORE GROUP FACULTY (~ 10)

Ashutosh Sharma (soft nano fabrication; nanomechanics)Ramesh C. Budhani (magnetic nanomaterials; spintronics)

V. N. Kulkarni (ion beams; fabrication)

Department of Chemical Engineering

Animangsu Ghatak (microfluidics; soft fabrication)Yogesh Joshi (polymer-clay nanocomposites)

Nishith Verma (carbon nanocomposites)Jayant K. Singh (simulations of soft materials)

Department of ChemistrySandeep Verma (self-assembly; nano-bio)

Department of Materials and Metallurgical EngineeringAshish Garg (thin films; nano-structures)

Department of Mechanical EngineeringShantanu Bhatacharya (nano-fabrication; MEMS)

Department of PhysicsRajiv Gupta (SPM; Raman)

(Additional members may be co-opted depending on the focus of research---soft materials based patterning and their

expertise in the Unit resources)

Major Facilities at Nanosciences Center

About 2500 sq. ft. of class 1000-100 clean rooms

Fabrication resources

Characterization resources

Collaborations: Northwestern; UIUC; UCI; Cambridge; NIST; JNCASR; IISc…….

Fall 2007

Fabrication

Focused Ion Beam (Dual Beam FIB)E-Beam LithographyBroad Beam Ion MillMaskless PhotolithographyPulse laserCoatingLangmuir-Blodgett DepositionNSOM UV LithographyNanoimprint LithographyPolymer Ink-jet Printing

High temperature furnaces…..

Characterization

Confocal MicroscopyMicro-RamanScanning Probe MicroscopiesNear-field Scanning Optical Microscopy (NSOM)Imaging and Spectroscopic EllipsometryProfilometers (Mechanical and Optical)SEMWAXRD; SAXSQUIDOptical MicroscopesContact Angle Goniometer……..

Specific Scientific Objectives:

Development of novel and facile techniques for patterning, structuring and fabrication using soft materials like polymers, gels, biological materials

Development of functional interfaces such as super-hydrophobic surfaces and super adhesives based on meso patterning of surfaces

Attachment –detachment energetics of sub-micron particles to surface and modulation by surfactants

Synthesis of ordered arrays of quantum dots and nanowires including doped oxide and metal alloys and magnetic materials

Exploration of interfacial instabilities and failure mechanism in soft nano-structures

Development of soft composites including polymer-nanoclay composites, thin film of meso-porous silica and its nano composites

Magnetic nano particles and assembliesDevelopment of computational nanomechanicsMicro-SQUIDS and nanoscale magnetics including

magnetic relaxation and supermagnetismFabrication of carbon meso-structures based on soft

fabrication techniquesMicrofluidic based devices and sensors

Current Areas of Nanosciences at IITK

Fabrication using FIB, E-beam (masters; devices…)

Novel soft-lithographies for large area, meso-patterning: “top-down” meets self-organization

Nano- mechanics of soft confined materials

Fabrication of novel MEMS: C-MEMS for micro-battery and cell-arrays

Nanocomposites: polymer, carbon, clays, silica...

Meso-textured Smart functional surfaces: superwetting; smart adhesives; optical and printing surfaces……

Interfacial/Colloidal interactions in aqueous media with polymer/surfactant adsorption

Stability of soft nanostructures including structures produced by nanoimprint lithography

Nanobiology: Scaffolds

Nanoparticles, nanofibres and nanofilms: semiconductors, metals, polymers, carbon, ceramics, organics…..

Nanostructured Magnetic Materials; spintronics

Nano-Patterning of Soft Materials

In devices; MEMS/NEMS; Sensors; Smart Surfaces; Micro-fluidics; Super-capacitors and Batteries; Smart Adhesives; Functional Interfaces………..

1.Facilities for large area, rapid patterning: Inkjet Printing, Gravure Printing, NanoimprintLithography, Laser Writing, FIB, E-beam……

2. Technology development for new patterning methods based on self-assembly, including e-field assisted patterning, phase change, dewetting,phase separation and stress-engineering, Nanocoatings; Fast micro/nano Texturing…….

3. Products:

Smart and Functional Surfaces by Patterning:

Adhesives,

Anti-reflective Coatings,

Structured Colors,

Anti-fouling,

Super-wetting

Carbon patterning: MEMS, High Area Batteries

Bio- and Chemical Sensors

Fluidic Devices

Opto-electronic Devices

Difficult to fabricate

Functional patterns

Additional Recent Nano-Grants:Self organized patterning of polymers, British Council (UKIERI), Rs. 2.4 millions (co-PI from UK: Prof. UllrichSteiner, Cambridge University).Carbon MEMS, part of Indo-US Center for Advanced and Futuristic Manufacturing, Indo-US Science and Technology Forum, 2006-2008. Rs. 6.4 million (Coordinator: Prof. Amitabha Ghosh; US collaborator: Prof. Marc Madou, UCI).Manufacturing Robust Nanostructures: Materials, Methods and Metrology, Indo-US Science and Technology Forum, Frontiers of Engineering (FOE) Award for collaboration with NIST Rs. 2.5 million. (US co-PI: Christopher Soles). Mesostructured Functional Thin Films and Interfaces of Soft Materials, Department of Science and Technology, 2007--2010. Rs. 49 million.Understanding adhesion of soft particles, Proctor & Gamble, 2008-2009. Rs.3 million

Some InnovationsA novel micro/nano fluidic adhesive has been prepared

and shown to be vastly more effectiveA novel nano fabrication method based on gel

miniaturization has been proposedThree novel methods for self-organized sub-micron

patterning of polymers on large areas have been developed and currently being further fine-tuned for applications.

A novel highly asymmetric nano-porous silica surface has been synthesized. One face of this surface is super-hydrophobic and the other is hydrophilic. Potential applications are in textile and barrier coatings.

Application of electric fields to pattern the surfaces of soft visco-ealstic materails on sub-micron lengthscalesby spatio-temporal variation of the e-field.

A novel technique for synthesis of colloidal solution of nanoparticles has been developed. This pulsed laser based method allows synthesis of multicomponent oxide and metal alloy nanoparticles, which is rather difficult to achieve with the know methods.

Stress tuning has been used to create novel 2-dimensional fractal networks of iron.

2006-07Over 70 publications in International Journals

3 patents filed and 1 disclosure

14 PhD students and several project staff trained

In addition to the Unit funding ~ 15 Carores, 6 additional nano related projects ~ 7 caroresgenerated; two industry supported

Collaborations with Cambridge, NIST, Lehigh, UIC, JNCASR, Saha Institute, TRDDC, NUS………..

Exciting new discoveries!!!!

Grand Challenges of Soft Patterning“Top-down” Meets Self-Organization!!

Sub-micron Features on Large areas (> cm; beyond!)

Rapid (m per second !! ); (roll-to-roll?; parallel)Integration across Different Materials (hydrogels,

ceramics, carbon……)Process Complexity; Resources, Cost….Patterning beyond Master: One Master, Many

SlavesIn-situ Tuning of PatternsProgrammable Patterning

Functional Nano-structured Interfaces: Smart-adhesives

Producing High Strength Re-usable Soft Adhesives: Bio-inspired Adhesion

Examples of Bioadhesives

Adhesive pads of insects

Setae of Gecko

Elastic Film

td h

F G,

J/m2

7 83 54 6210.0

0.3

0.6

0.9

1.2

1.5

1.8

9 10Microfluidic adhesive

(Majumder, Ghatak & Sharma; Science,2007)

Fabricating in ‘Exotic’ Functional Materials:Carbon: Micro/nano Webs and C-MEMS

Energy: micro battery, micro-fuel cell, super capacitor…. Electronics: molecular switches, memory……Biomaterials: C-MEMS…….Environment: Adsorption & catalytic media…

With Marc Madou, UCI

Difficult to Fabricate Functional Materials: Carbon Energy: micro-fuel cell, micro battery, super capacitor….; Biomaterials…….

Pyrolyzed Polymer structures !!

Stability: Stick

Functionalization:Carbon fibresCollaborator: Marc Madou, UCI

Nano-Imprinting Challenges:

Uniform high pressure/temperatureConformal contact/Curved surfacesStamp Removal

Meeting the ChallengesFlexible thin foil stampsSolvent vapor assisted softening of polymer filmsSpontaneous conformal contact by adhesive

forcesSoluble moulds/masters/stamps

Structural Colors by Micro-patterning: Adhesive Force Lithography with Flexible Foils: Variety of Surfaces and Materials

PS polymer;6 cm2

Hydrogel

Sharma et al., Macromolecules 2006Almost any polymer on any surface!!

Curved

Patterning Beyond Master : Pattern Miniaturization

400 nm structures starting from 800 nm masterSharma et al.

Patterning by Elastic Contact Instability: A New Micro/Nano Fabrication Toolpattern length scale ~ 3 H

A. Positive Replica

B. 2-D Bifurcation

C. Compress: Negative replica

D. Pull

E. Feature size reduction: Thin film

W ~ 2L Sharma et al. Langmuir 2006

Patterning by Electric Fields: A New Fabrication Tool

Sharma, Shenoy, Narayan et al., Adv Mat 2006

Controlled Self-organized Dewetting: A New Fabrication Tool

Sharma et al.

Robust Nanoimprint LithographySharma & Soles (NIST)

1. Imprinting of soft elastic films

2. Imprinting of viscous polymeric liquid films

ISSUES:A.Stress, strain, flow and structure relationshipsB.B. Stability and fidelity of imprinted structuresStability and fidelity of imprinted structuresC.C. MetrologyMetrology

m o ld ( S i , Q u a r tz )

im p r in t m a t e r i a ls u b s t r a te

r e l e a s e

R IE e t c h

im p r in t( f o r c e ,U V , h e a t )

m o ld ( S i , Q u a r tz )

im p r in t m a t e r i a ls u b s t r a te

r e l e a s e

R IE e t c h

im p r in t( f o r c e ,U V , h e a t )

Nano-Patterning of Surfaces by Self-assembly: Sandeep Vermaa

b

Adenine-Silver

Metallaquartet

HOPG

J. Am. Chem. Soc. 2006, 128, 400-401

Adenine-Silver

Duplex

HOPG

a b

J. Am. Chem. Soc. 2007, 129, 3488-3489

J. Am. Chem. Soc. 2006, 128, 400-401

ab

a b

J. Am. Chem. Soc. 2007, 129, 3488-3489

Sandeep Verma, Chemistry

Peptide morphologies

FFPP PPFF PFFPJ. Pep. Sci. 2007, 14, 118-126

Chem. Eur. J. 2008,14, 1415-1419

Angew. Chem. 2008,47, 2217-2221

Angew. Chem. 2008,47, 2860-2863

Laser Ablation Assisted Growth of Quantum Dots & Quantum Wires and Their Magnetic Properties

Ag colloid in aqueous SDS (R. Budhani et al.)

10 20 30 40

10

20

30

Cou

nts

D iam eter (nm )

(b)

50 nm50 nm (a)

(b)

-60 -30 0 30 60-600

0

600

Applied field (kOe)

Perpendicular In-plane

(f)

M (e

mu/

cc)

-600

0

600

TG = 750 0C

M (e

mu/

cc)

(e)

-600

0

600

-60 -30 0 30 60

TG = 700 0C

M (e

mu/

cc)

(d)TG = 700 0C

TG = 750 0C

TG = 800 0C

(a)

(b)

(c)2.0 μm

2.0 μm

2.0 μmSEM images and Perpendicular magnetization loops of 50 nm CoPt thin films deposited at various substrate temperatures at a growth rate of 0.4 Å/sec on single crystal STO (001). All the samples were post annealed for 25 minutes. Magnetization panel for the sample grown 800 0C also shows data for in-plane configuration.

CoPt Fractals and Nano dotsBudhani, Rakshit et al. Appl. Phys. Lett. 02511 (2006)

Fabrication using FIB

1. 2-D Patterning (masks, molds, stamps)

2. 3-D Structures (AFM tips, cantilevers, devices)

Focused Ion Beam: Nanomachining and Beyond

Sample(mounted on a precision

Ion Beam(Ga+ 3-30 KeV)Spot size 7 nm

ScanGeneratorfor SEM

ScanGenerator forFIB

Monitor

SED/SID

NN NO

VA

OVA

O

VA NN N

AN

OA

NO

AN

OLL L A

BA

BA

B

Nova NanoLabNova NanoLab Nano- Milling

Deposition

Micro Squid with NbFilms; Anjan Gupta et al.

EXAMPLES

Holes (100 nm dia.) drilled in NbSe2 for patterning the magnetic vortex states; Satyajit Banerjee et al.

Platinum electrodes separation 50 nm; I-V characteristics; Child Langmuir law at nanometer scales; S. Bhattacharjee

Superconducting Nano-Devices

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3

-4

-2

0

2

4

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3-20

0

20

40

60

80

100

120

140

160

dV/d

I in

ohm

Current in mA

PLOT of dV/dI vs I

volta

ge in

mV

Current in mA

V-I CHARACTERISTIC of Nb JJ

IC ~ 80 µA

(180(L) x 170(w) x 80(t) nm3)

-0.4 -0.2 0.0 0.2 0.4

-4

-2

0

2

4

Vol

tage

in m

V

Current in mA

V-I Characteristic of Nb SQUID (H=0)

-0.4 -0.2 0.0 0.2 0.4

0

10

20

30

40

dV/d

I in

ohm

Current in mA

SQUID Loop Area: (3.3 x 3.3) μm2

JJs:: 200(L) x 180(w) nm2

Maskless optical lithography + FIB milling; A. Gupta et al.

Carbon Cantilevers and Particles on AFM Tip

Kulkarni et al. Sharma et al.

AFM measurements of force-distance require dense spherical carbon particles 2-5 micronattached to the AFM tip

AFM Tips for Nanoindentation

AFM tip of well defined shapes are required; grown Tungsten tips of hemispherical shape with the required end radius of 50 nm

Sharma, Kar, Deva et al.

50 100 150 200 250 300 350 400 450 500-20

0

20

40

60

80

100

120

140

160

(z1,s1)

s [p

iezo

dis

plac

emen

t, nm

]

z [diflection, nm]

z =(z1-z2)

s = (s2-s1)

h = (z-s)(z2,s2)

tip movement

range of analysis

Fig 2. Vertical displacement

0.2 0.4 0.6 0.8 1.00

50

100

150

200

250

300

350

400

Ela

stic

mod

ulus

[MP

a]

h [indentation depth, nm]

Fig. 3 Modulus vs indentation depth

Meso-patterning of thin polymer films by atomic force microscope assisted electrohydrodynamic

nanolithography

Xie, Chung, Bandyopadhyay, Sharma, et al, J. Applied Phys. 103, 024307 (2008). selected paper in Virtual Journal of Nanoscale Science & Technology, 17 (5), 2008.

0th1st2nd

Fabrication of Small Things:

Top-Down

Bottom-up

Self-organization

Miniaturization

Ghatak, Sharma et al. Adv Mat (2007)

2006-07Over 70 publications in International Journals

3 patents filed and 1 disclosure

14 PhD students and several project staff trained

In addition to the Unit funding ~ 15 Carores, 6 additional nano related projects ~ 7 caroresgenerated

Collaborations with Cambridge, NIST, Lehigh, UIC, JNCASR, Saha Institute, TRDDC, NUS………..

Exciting new discoveries!!!!

Best way to predict the future is to invent it….