J. A. Barker

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New information on the electron-hole wave functions in InAs-GaAs self-assembled quantum dots is deduced from Stark effect spectroscopy. Most unexpectedly it is shown that the hole is localized towards the top of the dot, above the electron, an alignment that is inverted relative to the predictions of all recent calculations. We are able to obtain new(More)
We use a plane-wave technique to study the electron and hole wave functions in self-assembled InGaAs quantum rings, investigating the influence on the electron-hole overlap of variations in the ring shape and composition profiles, and including the effects of built-in strain and the piezoelectric potential. Lateral variation of the ground-state electron and(More)
We present a theoretical analysis of the mean electron and hole positions in self-assembled InAs-GaAs quantum-dot structures. Because of the asymmetric dot shape, the electron center of mass should be displaced with respect to the hole center of mass in such dots, giving rise to a built-in dipole moment. Theoretical calculations on ideal pyramidal dots(More)
We present far-/near-infrared double resonance measurements of self-assembled InAs/GaAs quantum dots. The far-infrared resonance is unambiguously associated with a bound-bound intraband transition in the neutral dots. The results show that the interband photoluminescence ͑PL͒ lines originate from conduction levels with successively increasing in-plane(More)
In this paper, the characteristics of organic bulk heterojunction solar cells have been designed and modeled using MATLAB R2010a version. Here, organic solar cell is considered as a diode and an equivalent circuit is developed with series and shunt resistances to obtain the I-V characteristics of the model. Non-linear equations are obtained in by solving(More)
Traffic Safety Administration, in the interest of information exchange. The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Department of Transportation or the National Highway Traffic Safety Administration. The United States Government assumes no liability for its content or use(More)
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