we report the growth by ion exchange synthesis of zns nanoparticles in mcm-41 matrices using zn (ch3coo)2 and na2s starting sources. the final product (zns/mcm-41) was characterized by x-ray diffraction (xrd) pattern, transmission electron microscopy (tem), scanning electron microscopy (sem), infrared spectrometry (ir) and uv-vis spectroscopy. its crystalline structure and morphology was studie...

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...

Background and Aims: Quantum dots (QDs), as colloidal nanocrystalline semiconductors, present QD wavelengths in terms of biomedical assays and imaging, though the high toxicity of their core demands to be taken into consideration. Investigating this subject is taken into account as an important concept   concerning use of these nanoparticles in the medical applications. Materials a...

We report transport measurements as a function of bias in open semiconductor quantum dots. These measurements are well described by an effective electron temperature derived from Joule heating at the point contacts and cooling by Wiedemann-Franz out-diffusion of thermal electrons. Using this model, we propose and analyze a quantum dot based sensor which measures absolute magnetic field at micro...

Semiconductor crystals smaller than about 10 nm, known as quantum dots, have properties that differ from large samples, including a band gap that becomes larger for smaller particles. These properties create several applications for quantum dots. In this paper new shapes of quantum dot arrays are used to enhance the photo physical properties of gold nano-particles. This paper presents a study o...

Quantum computing and quantum communication are remarkable examples of new information processing technologies that arise from the coherent manipulation of spins in nanostructures. We review our theoretical proposal for using electron spins in quantum-confined nanostructures as qubits. We present singleand two-qubit gate mechanisms in laterally as well as vertically coupled quantum dots and dis...

Based on an idea that spatial separation of charge states can enhance quantum coherence, we propose a scheme for a quantum computation with the quantum bit ~qubit! constructed from two coupled quantum dots. Quantum information is stored in the electron-hole pair state with the electron and hole located in different dots, which enables the qubit state to be very long-lived. Universal quantum gat...

MRI detectable and targeted quantum dots were developed. To that aim, quantum dots were coated with paramagnetic and pegylated lipids, which resulted in a relaxivity, r(1), of nearly 2000 mM(-1)s(-1) per quantum dot. The quantum dots were functionalized by covalently linking alphavbeta3-specific RGD peptides, and the specificity was assessed and confirmed on cultured endothelial cells. The bimo...

We present a fabrication method to produce site-controlled and regularly spaced InAs/GaAs quantum dots for applications in quantum optical information devices. The high selectivity of our epitaxial regrowth procedure can be used to allocate the quantum dots only in positions predefined by ex-situ local oxidation atomic force nanolithography. The quantum dots obtained following this fabrication ...

The inter-sub-level transitions in modulation-doped Ge quantum dots are observed. The dot structure is grown by molecular-beam epitaxy, and consists of 30 periods of Ge quantum dots sandwiched by two 6 nm boron-doped Si layers. An absorption peak in the midinfrared range is observed at room temperature by Fourier transform infrared spectroscopy, which is attributed to the transitions between th...