Quantum Dotsdots

QuantumQuantum DotsDots

BrittanyBrittany WebbWebb DepartmentsDepartments ofof ChemistryChemistry andand PhysicsPhysics UtahUtah StateState UniversityUniversity

Size: 2.3nm 5nm

Source: http://www.greenspine.ca/media/quantum_dots_c.jpg WhyWhy QuantumQuantum Dots?Dots?

II chosechose toto researchresearch quantumquantum dotsdots becausebecause ofof anan articlearticle thatthat II readread inin aa magazinemagazine overover thethe summer.summer. II thoughtthought thatthat quantumquantum dotsdots soundedsounded likelike theythey hadhad aa lotlot ofof applicationsapplications andand II wantedwanted toto knowknow howhow theythey camecame upup withwith thethe idea.idea. II learnedlearned aa lotlot aboutabout themthem andand havehave comecome toto thethe conclusionconclusion thatthat theythey arenaren’’tt asas coolcool asas II originallyoriginally thoughtthought theythey werewere –– THEYTHEY’’RERE BETTER!BETTER! WhatWhat areare QuantumQuantum Dots?Dots?

QuantumQuantum dotsdots areare semiconductorsemiconductor nanocrystalsnanocrystals thatthat areare soso smallsmall theythey areare consideredconsidered dimensionless.dimensionless. QuantumQuantum dotsdots rangerange fromfrom 22--1010 nanometersnanometers (10(10--5050 atoms)atoms) inin diameter.diameter. AnimationAnimation QuickQuick ReviewReview ofof SemiconductorsSemiconductors

A semiconductor is a material that has a small band gap between the valence and conduction band. An exciton pair is defined as an electron and the hole that it leaves behind when it is excited up to the conduction band. An exciton bohr radius is the distance in an electron-hole pair. A Quantum Dot is a semiconductor so small that the size of the crystal is on the same order as the size of the exciton bohr radius. This unique size property causes the “band” of energies to turn into discrete energy levels.

Source: http://www.smtresource.com/web/images/sections/icon-semi-150x150.jpg http://www.export-japan.com/hocci/worldmetal/img/worldmetal01.jpg http://www.cpu-world.com/CPUs/32081/L_NS-NS32081D-6.jpg ArtificialArtificial Atoms?Atoms?

QuantumQuantum DotsDots areare moremore closelyclosely relatedrelated toto atomsatoms thanthan aa bulkbulk materialmaterial becausebecause ofof theirtheir discrete,discrete, quantizedquantized energyenergy levels.levels. TheyThey havehave beenbeen nicknamednicknamed ArtificialArtificial Atoms.Atoms.

Source: http://www.nanop.de/animationen/graifkdateien/Mocvd_5.jpg ExcitonExciton BohrBohr RadiusRadius && TheThe BandBand GapGap

BandBand Gaps,Gaps, andand thereforetherefore thethe energyenergy associatedassociated withwith them,them, dependdepend onon thethe relationshiprelationship betweenbetween thethe sizesize ofof thethe crystalcrystal andand thethe excitonexciton bohrbohr radius.radius. AnimationAnimation

Source: http://www.evidenttech.com/qdot-definition/flash-player.php?mov=07_quantum_confine ColorificColorific PropertiesProperties

TheThe height,height, andand energyenergy difference,difference, betweenbetween energyenergy levelslevels increasesincreases asas thethe sizesize ofof thethe quantumquantum dotdot decreasesdecreases (remember(remember thethe animationanimation wewe justjust saw).saw). Smaller Dot = Higher Energy = Smaller Wavelength = Blue Color

Source: http://www.evidenttech.com/qdot-definition/flash-player.php?mov=08_tunable ColorColor andand QuantumQuantum DotsDots

Source: http://optics.org/objects/news/7/7/2/Quantumdottag.jpg http://www.qdots.com/live/images/figure9.gif ApplicationsApplications ofof QuantumQuantum DotsDots

Source: http://www.evidenttech.com/applications/quantum-dot-applications.php FutureFuture ApplicationsApplications ofof QuantumQuantum DotsDots

WhiteWhite LEDLED’’ss –– ReplaceReplace IncandescentIncandescent LightLight bulbsbulbs withwith red,red, green,green, andand blueblue QDQD’’ss toto getget whitewhite light.light. ActiveActive LEDLED’’ss –– cancan getget anyany colorcolor neededneeded virtuallyvirtually painpain free;free; sincesince QDQD’’ss areare soso small,small, theythey cancan bebe insertedinserted intointo basicallybasically anything.anything. LifeLife SciencesSciences –– CanCan bebe usedused inin placeplace ofof traditionaltraditional organicorganic dyes;dyes; lastlast longerlonger andand cancan bebe tunedtuned moremore specificallyspecifically thanthan organicorganic dyes.dyes. ApplicationsApplications -- CircuitsCircuits

By adding “quantum wires” to a quantum dot, many quantum dots have been strung together in various shapes and structures. Hypothetically, these quantum dot/wire structures could be used in circuits in place of traditional wires.

Source: http://www.llnl.gov/str/Lee.html ConclusionsConclusions

QuantumQuantum DotsDots areare aa newnew andand innovativeinnovative perspectiveperspective onon thethe traditionaltraditional semiconductor.semiconductor. QuantumQuantum DotsDots cancan bebe synthesizedsynthesized toto bebe essentiallyessentially anyany size,size, andand therefore,therefore, produceproduce essentiallyessentially anyany wavelengthwavelength ofof light.light. ThereThere areare manymany possiblepossible applicationsapplications ofof QuantumQuantum DotsDots inin manymany differentdifferent areasareas ofof industry/science.industry/science. TheThe futurefuture lookslooks brightbright andand excitingexciting onon allall thethe possiblepossible applicationsapplications ofof QuantumQuantum Dots.Dots. AcknowledgementsAcknowledgements

II wouldwould likelike toto thankthank thethe EvidentEvident TechnologyTechnology companycompany and,and, moremore specifically,specifically, theirtheir ITIT peoplepeople forfor thethe greatgreat animationsanimations theythey havehave created.created.