Novel quantum-dot-tagged photonic crystal beads were fabricated for multiplex detection of tumor markers via self-assembly of quantum dot-embedded polystyrene nanospheres into photonic crystal beads through a microfluidic device.

This thesis describes the first realization and initial measurements of a linear array of seven quantum dots. The device was fabricated on a high mobility GaAs/AlGaAs heterostructure. Electron beam lithography was used to pattern critical features of the device, and 70 nm resolution was achieved. A 3He probe was used to measure the device at 300 mK. The design of the device allowed individual c...

This thesis presents the development of an on-demand source of time-bin entangled photons, created from the biexciton-exciton radiative cascade in a single quantum dot. To achieve a source of time-bin entangled photons, we determined that the quantum dot must have two key properties: a dephasing time that is longer than the lifetime and high count rates, which are necessary to perform the corre...

A model that explains the unusual characteristics of the AlGaAs/GaAs modulation-doped field-effect transistor (MODFET) with InAs quantum dots incorporated in the GaAs channel is presented. It is shown that the negative charge of electrons confined in quantum dots decreases the threshold gate–drain voltage at which the channel is fully depleted. This provides an impact ionization of quantum dots...

Quantum-dot cellular automata ~QCA!, arrays of coupled quantum-dot devices, are proposed for quantum computing. The notion of coherent QCA ~CQCA! is introduced in order to distinguish QCA applied to quantum computing from classical digital QCA. Information is encoded in the spatial state of the electrons in the multidot system. A line of CQCA cells can work as a quantum register. The basic sing...

We study the transport behavior induced by a small bias voltage through a quantum dot connected to one-channel finite-size wires. We describe the quantum dot using the Hubbard-Anderson impurity model and we obtain solutions by means of a quantum Monte Carlo method. We investigate the effect of a magnetic field applied at the quantum dot in the Kondo regime. We identify mesoscopic oscillations i...

We report on the reversible electrical control of the magnetic properties of a single Mn atom in an individual quantum dot. Our device permits us to prepare the dot in states with three different electric charges, 0, +1e, and -1e which result in dramatically different spin properties, as revealed by photoluminescence. Whereas in the neutral configuration the quantum dot is paramagnetic, the ele...

We analyze here a model for single-electron charging in semiconductor quantum dots that includes the standard Anderson on-site repulsion (U) as well as the spin-exchange (Jd) that is inherently present among the electrons occupying the various quantum levels of the dot. We show explicitly that for ferromagnetic coupling (Jd > 0), an s-d exchange for an S=1 Kondo problem is recovered. In contras...

Quantum dots are new types of fluorescent materials for biological labeling. As a result, QDs toxicity study is an essential requirement for future clinical applications. Therefore, the cytotoxic CdSe:ZnS quantum dots effects on some organs in mice are presented in this study. In this work, 10, 20 and 40 mg/kg doses of CdSe:ZnS quantum dots were injected to 32 adult male mice. Structural and op...