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Quantum dots laser diodes using the dots-in-a-well (DWELL) structure (InAs dots in an InGaAs quantum wells) have exhibited significant recent progress. With a single InAs dot layer in Inoi5Gao.8sAs quantum well, threshold current densities are as low as 26 A cm2 at 1 .25 xm. Quantum dot laser threshold current densities are now lower than any other reported semiconductor laser. In this work, th...

Quantum-dot cellular automata (QCA) are an emerging technology and a possible alternative for faster speed, smaller size, and low power consumption than semiconductor transistor based technologies. Previously, adder designs based on conventional designs were examined for implementation with QCA technology. This paper utilizes the QCA characteristics to design a fault-tolerant adder that is more...

We demonstrate that external cavity diode lasers with large mode-hop-free tuning ranges ~up to 80 GHz! together with wavelength modulation spectroscopy can be used to study excitonic transitions in semiconductor nanostructures. Such transitions are characterized by homogeneous linewidths typically on the order of a few GHz. Wavelength modulation spectroscopy offers a high signal-to-noise method...

application of quantum-dot is a promising technology for implementing digital systems at nano-scale.  quantum-dot cellular automata (qca) is a system with low power consumption and a potentially high density and regularity. also, qca supports the new devices with nanotechnology architecture. this technique works based on electron interactions inside quantum-dots leading to emergence of quantum ...

The Andreev spectrum of a quantum dot embedded in hybrid semiconductor-superconductor interferometer can be modulated by electrostatic gating, magnetic flux through the interferometer, and Zeeman splitting from in-plane field. We demonstrate parity transitions system, show that Zeeman-driven transition is accompanied 0-{\pi} superconducting phase across dot. further modulates both transitions.

We provide a microscopic theory for semiconductor quantum dots that explains the pronounced deviations from the prevalent point-dipole description that were recently observed in spectroscopic experiments on quantum dots in photonic nanostructures. The deviations originate from structural inhomogeneities generating a large circular quantum current density that flows inside the quantum dot over m...

– We suggest a series of transport experiments on spin precession in quantum dots coupled to one or two ferromagnetic leads. Dot spin states are created by spin injection and analyzed via the linear conductance through the dot, while an applied magnetic field gives rise to the Hanle effect. Such a Hanle experiment can be used to determine the spin lifetime in the quantum dot, to measure the spi...