[Audio] ECE 656: Electronic Transport in Semiconductors (Fall 2009)

Outline:Schottky barriersTransport across a thin baseHigh-field collectors

Outline:Review of velocity overshootSteady-state, spatial transientsHeterojunction launching rampsRepeated velocity overshootQuestions?

Outline:Brief IntroductionCurrent EquationQualitative features of high field transportSaturated velocityElectron temperature modelSurvey of resultsQuick Summary

Outline:IntroductionReview of carrier scatteringSimulating carrier trajectoriesFree flightCollisionUpdate after collisionPutting it all togetherSummary

OutlineCarrier Temperature and Heat FluxBalance equations in 3DHeterostructuresSummary

Outline:Review of high-field transportMC simulation of high-field transportVelocity overshootSummary

Outline:Quick reviewEnergy balance equationEnergy flux balance equationTerminating the hierarchySummary

Outline:IntroductionGeneral continuity equationCarrier continuity equationCurrent equationSummary

Outline:Umklapp processesOverlap integralsADP Scattering in graphene

The goal in this lecture is to examine one scattering mechanism (ADP scattering) in 3D, 2D, and 1D to see how the scattering rate changes with dimensionality. Then we’ll compare mobilities in 3D, 2D, and 1D.Outline:Review of ADP Scattering in 3DADP Scattering in 2D: MCAADP Scattering in 2D: FGRADP Scattering in 1D: FGRMobility in 1D, 2D, and 3D

Outline:ReviewPOP and IV scatteringScattering in common semiconductorsElectron-electron scatteringSummary

Outline:Review Energy-momentum conservationMathematical formulationExampleSummary

Outline:About phononsElectron-phonon couplingEnergy-momentum conservationSummary

Outline:General solutionCurrent equationCoupled current equationsExampleSummary

Online:ReviewScreeningBrooks-Herring approachConwell-Weisskopf approachDiscussionSummary / Questions

OutlineMagnetoconductivity tensorResistivity tensorStrong B-fields: Landau levelsShubnikov-DeHaas Oscillations and QHESummary

Outline:Transmission and mfpMFP and carrrier scatteringExtracting mean-free-paths from experiments

Outline:Fermi’s Golden RuleExample: static potentialExample: oscillating potentialDiscussionSummary

Outline:Characteristic timesRelaxation Time Approximation and τr

Outline:The RTA Solving the BTE: driftSolving the BTE: diffusionEnergy-dependent scattering timeRelation to LandauerDiscussionSummary

Outline:P-type conductors and thermoelectricsZT figure of meritMaximizing the “power factor”TE parameters for non-degenerate semiconductor

General solution 2) Current equation 3) Coupled current equations 4) The RTA 5) Summary

Outline:BTE reviewTransport DistributionConnection to LandauerModesMean-free-pathSummary

Outline:Transport in the bulkThe DD equationIndicial notationDD equation with B-field

Outline:Onsager relationsMeasurement considerationsThermoelectric devices

Outline:IntroductionOne energy level formulationDistribution of energy levelsDiscussionSummary

Outline:Another view of the same problem2D resistorsDiscussion3D resistorsSummary

Outline:Quick reviewEquilibrium BTEBallistic BTEDiscussionSummary

Outline:IntroductionSemi-classical electron dynamics Boltzmann Transport Equation (BTE) ScatteringDiscussionSummary

OutlineQuantum confinement and effective massBulk 1D transport and mfpPeriodic vs. Box boundary conditionsThermal velocities"Ballistic mobility"

Outline:Review1D ballistic resistors1D diffusive resistorsDiscussionSummary

Outline:Density of states Example: graphene Density of modes Example: graphene Summary

Outline:General model for low-field transportModesTransmissionLinear (near equilibrium) transportSummary

Outline:Density of states in k-space Example Working in energy space Discussion Summary

Outline:Bandstructure in bulk semiconductorsQuantum confinementSummary