Slide 1What is it all about?Cleaved Edge Overgrowth - Fabrication IGrowth of InAs Structures on Cleaved GaAs/AlAs - Fabrication IIPhenomenological Growth ModelsMechanism for GrowthTwin-Dot ArraysBUT! Also growth on GaAs regionsConclusionControlled Synthesis of InAs Wires, Dot and Twin-Dot Array configurations by Cleaved Edge OvergrowthE. Uccelli, M. Bichler, S. Nürnberger, G. Abstreiter, A. Fontcuberta i Morral Nanotechnology 19, 2008What is it all about?Control of size and thereby emission properties of QDs is possible but control of position is more challengingIn situ cleaved edge overgrowth to control the nucleation of InAs QDsUccelli, Bichler, Nürnberger, Abstreiter and Fontcuberta i MorralCleaved Edge Overgrowth- Fabrication ILef: L. Pfeiffer et al., Appl. Phys. Lett. 56, 1697 (1990)Right: G. Schedelbeck et al., Science 278, 1792 (1997)Growth of InAs Structures on Cleaved GaAs/AlAs- Fabrication IIStranski-Krastanov growth modePhenomenological Growth ModelsLayer-by-layerFrank-van der MerveLayer-plus-islandStranski-KrastanovIslandVollmer-Weberγs = γsf + γf cosφ γs ≥ γsf + γf + CkBT ln(p0/p) γs < γsf + γf + CkBT ln(p0/p)Mechanism for Growth1 ML = 2.83 ÅMLLLdMLLDdhAlAsGaAsGaAsAlAsAlAs2Twin-Dot ArraysBUT! Also growth on GaAs regionsConclusion•Atomic precison of MBE used for positioning of QDs and other structures•Technique seems limited to simple geometries because of the use of cleavage planes•Small window for preferential growth on AlAs but it is
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