High anisotropy of lateral alignment in multilayered (In,Ga)As∕GaAs(100) quantum dot structures

Wang, Zh. M.; Churchill, H.; George, C. E.; Salamo, G. J.

doi:doi:10.1063/1.1815382

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We investigate the effect of a thin alumina coating of nanocrystalline TiO2 films on recombination dynamics of dye-sensitized solar cells. Both coated and uncoated cells were measured by a combination of techniques: transient absorption spectroscopy, electrochemical impedance spectroscopy, and open-circuit voltage decay. It is found that the alumina barrier reduces the recombination of photoinjected electrons to both dye cations and the oxidized redox couple. It is proposed that this observed re...

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A formation process for long chains of quantum dots during the molecular-beam epitaxial growth of (In,Ga)As∕GaAs(100) multilayers is presented. The morphology evolution monitored by atomic force microscopy for a series of (In,Ga)As layers demonstrates that the highly anisotropic lateral alignment of dots is gradually developed as the result of the strain field interaction mediated by the GaAs spacer coupled with the anisotropic surface kinetics that occurs during capping the dots. The dot-chain structure, providing unique properties of its own, is demonstrated to serve as a template for the spatially controlled growth of strained quantum dots in general.