Self-Organization of InAs/InP Quantum Dot MultilayersOverviewMotivationStranski-Krastanov growthSlide 5Slide 6Slide 72 Regimes of Self-organizationQuantum Dot Array ModelingExperimental ResultsAtomistic Strain CalculationsConclusionsSelf-Organization of InAs/InP Quantum Dot MultilayersNavdeep Singh DhillonOverview Regimes of 3-D self-organization in quantum dot layers described using–Experimental observations for InAs/InP(001) system–Atomistic Strain calculationsPseudophase diagram developed to explain transition from vertically aligned to anti-aligned layersMotivationPeriodicity and size uniformity of quantum dots grown in Stranski-Krastanov mode important for device applicationsDetailed understanding of physical origin of phenomena prerequisite for obtaining the required 3-D arrangement for particular applicationStranski-Krastanov growth InP(001) substrateLow-Pressure Metal-Organic Vapor Phase Epitaxy in a cold-wall reactorStranski-Krastanov growth InP substrateInAs3-7 ML of InAs is depositedStranski-Krastanov growth InP substrateInAs Islands60 s treatment in TBAs/H2 ambientThe InAs monolayers form islands due to Interlayer StrainStranski-Krastanov growth InP substrateInAs IslandsDeposit Spacer layer and repeat2 Regimes of Self-organizationVertically Aligned (VA) Anti-Aligned (AA)Quantum Dot Array ModelingH Spacer Thicknessh QD heigthb QD baseD Lateral SpacingC Vertically aligned pointA1, A2, A3Anti-aligned pointsExperimental ResultsAlignment depends mainly on H/DSlight dependence on b/DNo direct dependence on hAtomistic Strain CalculationsKeating’s valence force field methodAtomic coordinates relaxed using a conjugate-gradient algorithm until a minimum of elastic energy is found16.6 < D < 29 nm3.3 < b < 15.8 nm1.2 < h < 3.6 nmConclusionsSelf-organization of quantum dot multilayers–Spacer layer thickness (H)–Areal density of islands (D)–Lateral dimension (b) (to a lesser extent)
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