Dimensional control in nanostructure.pdf

Nano structure and dimensional control in it.

1. DIMENSIONAL CONTROL
IN NANOSTRUCTURE
ToobaAYUB
ROLL NO 0291–BH-CHEM-20.

2. Contents.
1.introduction.
2.Nanostructure
3.Dimensional control in Nano structure.
4.Classification of nanostructure on the basis of dimensional .
5.Methods for dimensional control.
Top-downfabricationtechniques(e.g.,lithography,etching)
Bottom-upfabricationtechniques(e.g.,chemicalvapourdeposition,self-assembly)
Hybridapproaches(combiningtop-downandbottom-upmethods.
6.Factorsaffectingdimensionalcontrol.
7.ExamplesofNanostructuresindimensionalcontrol.
8.Challengesadfutureperspective.

3. INTRODUCTION.
Nano structure.
Nanostructures generally refer to the material systems that
are in the range of 1 to 100 nanometers.OR Nanostructure
is a structure that has at least one dimension in the
nanometre scale, typically ranging from 1 to 100
nanometres.

4. Dimensional control in Nano structure.
Dimensionalcontrolreferstotheabilitytomaintainthedimensions(suchassize,shape,and
orientation)ofastructureorobjectwithindesiredtolerances.Inthecontextofnanostructures,
dimensionalcontroliscrucialbecausethephysicalandchemicalpropertiesofmaterialsatthe
Nanoscalearehighlysensitivetovariationsinsizeandshape.
Dimensionalcontrolisessentialinnanotechnologybecausemanypropertiesandbehavioursof
materialsattheNanoscalearesize-dependent.Forexample,theoptical,electronic,and
mechanicalpropertiesofnanoparticlescanvarysignificantlydependingontheirsizeandshape.
Therefore,precisedimensionalcontrolisessentialfortailoringthesepropertiesforvarious
applications,suchasinelectronics,catalysis,sensing,andmedicine.

5. Classification of nanostructure on the basis of dimensions.
Ananostructureisastructurethathas
atleastonedimensioninthenanometre
scale,typicallyrangingfrom1to100
nanometres.Nanostructurescanbe
classifiedintodifferentdimensions.
.

6. OD(ZERODIMENSIONAL STRUCTURE)
0D nanostructures.
Zero-Dimensional(0D)Nanomaterial's.
Thematerialswhosedimensionsareall
undernanometrerangebelongtozero-
dimensional (0D) nanomaterial's.
Nanoparticles,quantumdots,carbonNano
dots,fullerene,etc.aresomepopular
examplesof0Dnanomaterial's

7. 1D one dimensional nanostructure
1D nanostructures:
One-dimensionalnanostructuresareNano
scalestructuresthatextendinone
dimension,suchasnanowires,Nanorods,
ornanotubes.Theyhavetwodimensions
intheNanoscalerange.

8. 2D two dimensional structure.
2Dnanostructures:
Two-dimensionalnanostructuresareNano
scalestructuresthatextendintwo
dimensions,suchasthinfilms,Nano
sheets,orgraphene.Theyhaveone
dimensionintheNanoscalerange.

9. 3D Three dimensional Nano structure
3D nanostructures:
Extendinallthreedimensions,possessing
length,width,andheight.
Examplesincludenanotubes,Nano
spheres,andcomplexnanostructureswith
intricate3Dshapes.
3Dnanomaterial'scanbesynthesizedin
variousshapeslikespheres,tubes,
gyroids,etc.Thisallowstheoptimizationof
shapesfordifferentapplications.

10. Methods for the dimensional control.
Top-downfabricationtechniques
Thisisamethodsusedtocreatenanostructures
bystartingwithlargerbulkmaterialsandthen
reducingtheirsizetotheNanoscale.These
techniquesarecalled"top-down"becausethey
startfromthelargerscaleandprogressively
removematerialtoreachthedesired
nanostructuresize.

11. Somecommontop-downfabricationtechniquesinclude:
Lithography:
Lithographyusesmasksandlight(orelectronbeams)toselectivelyremoveormodifymaterialona
substrate,creatingpatternswithNanoscalefeatures.Therearevarioustypesoflithography,suchas
photolithography,electronbeamlithography,andNanoimprintlithography.
Etching:
Etchinginvolvesselectivelyremovingmaterialfromasubstrateusingchemical,physical,or
electrochemicalprocesses.Commonetchingtechniquesfornanofabricationincludereactiveion
etching(RIE),deepreactiveionetching(DRIE),andwetchemicaletching.

12. Bottom up fabrication technique.
Bottom-upfabricationtechniquesare
methodsusedtocreatenanostructuresby
buildingthemupfromindividualatomsor
molecules.Thesetechniquesarecalled
"bottom-up"becausetheystartwiththe
smallestbuildingblocksandassemble
themintolargerstructures,oftenthrough
self-assemblyorchemicalsynthesis
processes.

13. Somecommonbottom-upfabricationtechniquesinclude:
1.ChemicalVapourDeposition(CVD):
CVDisamethodwherethinfilmsofmaterialaredepositedontoasubstratebyreactinggaseous
precursormoleculesonthesubstratesurface,leadingtotheformationofnanostructures.
1.Self-Assembly:
Self-assemblyisaprocesswheremoleculesornanoparticlesspontaneouslyorganizeintoordered
structureswithoutexternalmanipulation.Thiscanincludeprocesseslikemolecularself-assembly,
wheremoleculesformstructuresbasedontheirchemicalproperties.

14. Hybrid approaches.
Hybridapproachesinnanofabricationrefer
totechniquesthatcombineelementsof
bothtop-downandbottom-upapproaches.
Theseapproachesleveragethestrengths
ofeachmethodtoovercomelimitations
andachievemoreprecisecontroloverthe
fabricationprocessandtheresulting
nanostructures.

15. DirectedSelf-Assembly(DSA):
DSAcombinestheprinciplesofself-assemblywithtop-downpatterningtechniques.Atop-down
patterniscreatedonthesubstrate,whichthendirectstheself-assemblyofmoleculesor
nanoparticlesintothedesirednanostructure.Thisapproachallowsforthecreationofordered
nanostructureswithprecisecontroloverplacementandorientation.
CombinationofEtchingandDeposition:
Inthisapproach,atop-downmethodsuchasetchingisusedtocreatepatternsorfeaturesonthe
substrate,whicharethenfilledorcoatedwithmaterialusingabottom-upmethodsuchaschemical
vapordeposition(CVD)oratomiclayerdeposition(ALD).Thisallowsforthecreationof
nanostructureswithcontrolleddimensionsandcompositions.

16. Factors affecting dimensional control.
Severalfactorscanaffectdimensionalcontrolinthefabricationofnanostructures.
Thesefactorscanvarydependingonthefabricationtechniqueused,butsome
commononesinclude.
Processparameter.
Materialproperties.
Processstability.
Materialinteraction.
Surfaceeffect

17. Factors affecting the dimensional control.
1.ProcessParameters:Parameterssuchastemperature,pressure,anddepositionrate
cansignificantlyaffectthegrowthandassemblyofnanostructures.Variationsinthese
parameterscanleadtochangesinthesize,shape,andstructureofnanostructures.
2.MaterialProperties:Thepropertiesofthematerialsusedcaninfluencedimensional
control.Factorssuchascrystalstructure,surfaceenergy,andchemicalcompositioncan
affecthowmaterialsnucleate,grow,andassembleintonanostructures.

18. 3.ProcessStability:Thestabilityandconsistencyofthefabricationprocessarecrucialfor
dimensionalcontrol.Variationsorfluctuationsintheprocesscanleadtovariationsinthesize,shape,
andqualityofthenanostructures.
4.InteractionForces:ForcessuchasvanderWaalsforces,electrostaticforces,andcapillaryforces
caninfluencetheassemblyandarrangementofnanostructures,affectingtheirdimensionsand
properties.
5.SurfaceEffects:Surfaceinteractionsbetweenthenanostructuresandthesubstrateorsurrounding
environmentcanaffectdimensionalcontrol.Surfaceenergy,surfaceroughness,andsurfacechemistry
canallplayaroleindeterminingthefinaldimensionsofnanostructures.
Factors effecting dimensional control.

19. Process
parameter
Material
properties
Process
stability
Interaction
forces
Surface
effect

20. Example of dimensional control in nanostructure.
Oneexampleofdimensionalcontrolin
nanostructuresisthefabricationofsemiconductor
quantumdots(QDs).QuantumdotsareNano
scalesemiconductorparticleswithuniqueoptical
andelectronicpropertiesthatdependontheir
sizeandcomposition.Controllingthedimensions
ofquantumdotsiscrucialfortuningtheir
propertiesforvariousapplications,suchasin
quantumdotdisplays,solarcells,andbiological
imaging.

21. Example of dimensional control in nanostructure
Toachievedimensionalcontrolinquantumdots,researchersuseacombinationoftop-downand
bottom-upfabricationtechniques.Forexample,inatypicalprocess:
Bottom-upsynthesis:
Semiconductormaterialsaresynthesizedinsolution-phasereactionstoformNanocrystals.The
sizeofthequantumdotscanbecontrolledbyadjustingthereactionconditions,suchasthe
temperature,reactiontime,andtheratioofprecursormaterials.
Sizeselection:
Aftersynthesis,thequantumdotsareoftendispersedinasolutioncontainingligandsthatcan
selectivelybindtoquantumdotsofaspecificsize.Thissizeselectionstephelpstoisolate
quantumdotswiththedesireddimensions.

22. Example of dimensional control in Nano structure
Surfacemodification:
Thesurfaceofthequantumdotscanbemodifiedtoimprovetheirstabilityandoptical
properties.Ligandsorcappingagentscanbeaddedtothesurfacetopassivate
defectsandpreventaggregation.
Top-downpatterning:
Insomecases,top-downlithographictechniquescanbeusedtopatternthesubstrate
orcreatetemplatesforthedepositionofquantumdots.Thisapproachcanfurther
controlthespatialarrangementanddimensionsofthequantumdots.

23. Challenges and future perspective
Challengesindimensionalcontrolofnanostructuresinclude:
Uniformity:Achievinguniformsizeandshapeacrossalargeareaorbatchofnanostructurescan
bechallengingduetovariationsinfabricationprocesses.
Resolution:Currentfabricationtechniquesmayhavelimitationsinachievinghighresolutionand
precisecontroloverdimensions,especiallyforcomplexnanostructures.
Scalability:Somefabricationtechniquesmaynotbeeasilyscalabletolarge-scaleproduction,
limitingthepracticalapplicationsofnanostructures.
Cost:Fabricationofnanostructuresusingcertaintechniquescanbeexpensive,whichmayhinder
theirwidespreadadoption.

24. Challenges and future perspective
AdvancedFabricationTechniques:Developmentofnovelfabricationtechniques
withhigherresolution,bettercontrol,andscalability,suchasadvancedlithography,
self-assembly,andtemplate-assistedmethods.
Multi-DimensionalControl:Achievingcontrolovermultipledimensions(size,shape,
orientation)simultaneouslytocreatecomplexnanostructureswithtailoredproperties.
In-situCharacterization:Integrationofin-situcharacterizationtechniquestomonitor
andcontrolthefabricationprocessinreal-time,improvingcontrolanduniformity.

25. Applications of dimensional control in nanostructure
Dimensional control in nanostructures is crucial for various applications across
different fields. Some key applications include.
electronicscatalysis
Biomedical
imaging
Drug
delivery
sensing

26. Applications of dimensional control in nanostructure.
Dimensionalcontrolinnanostructuresiscrucialforvariousapplicationsacrossdifferent
fields.Somekeyapplicationsinclude:
Electronics:Inelectronics,precisecontroloverthedimensionsofnanostructuresis
essentialfordevelopingsmaller,faster,andmoreenergy-efficientdevices.Forexample,
quantumdotswithwell-definedsizescanbeusedinquantumdotdisplaysandquantum
dotsolarcells.
Catalysis:Nanostructureswithcontrolleddimensionscanexhibitenhancedcatalytic
propertiesduetotheirhighsurfacearea-to-volumeratio.Thesenanostructuresareusedin
catalyticconverters,fuelcells,andotherenvironmentalandenergy-relatedapplications.

27. Applications of dimensional control in nanostructure.
Biomedical Imaging:Quantum dots and other nanostructures with controlled dimensions are
used as contrast agents in biomedical imaging techniques such as fluorescence imaging and
magnetic resonance imaging (MRI).
Drug Delivery:Nanostructures with precise dimensions can be used to encapsulate drugs and
deliver them to specific targets in the body, improving the efficacy and reducing the side effects of
drug treatments.
Sensing:Nanostructures with controlled dimensions are used in sensors for detecting various
analytessuch as gases, chemicals, and biomolecules. The high surface area-to-volume ratio of
nanostructures enhances sensitivity and response times in sensing applications.

28. Applications od dimensional control in nanostructure
EnergyStorageandConversion:
Nanostructureswithcontrolleddimensionsareusedinbatteries,supercapacitors,andfuelcells
toimproveenergystorageandconversionefficiency.Forexample,nanowiresandnanotubes
areusedtoimprovetheperformanceoflithium-ionbatteries.
Optoelectronics:
Nanostructureswithcontrolleddimensionsareusedinoptoelectronicdevicessuchaslight-
emittingdiodes(LEDs),solarcells,andphotodetectors.Precisecontroloverthedimensionsof
thesestructuresisessentialforoptimizingtheiropticalandelectronicproperties.

29. Conclusion.
Inconclusion,dimensionalcontrolinnanostructuresplaysa
crucialroleintailoringtheirpropertiesforspecific
applications.Variousfabricationtechniques,includingtop-
downandbottom-upapproaches,areusedtoachieve
precisecontroloverthesize,shape,andorientationof
nanostructures.Challengessuchasuniformity,resolution,
scalability,andcostexistinachievingdimensionalcontrol,but
advancementsinfabricationtechniquesandmaterials
scienceareaddressingthesechallenges.

30. THANK YOU