Search

The scattering processes of electrons in semiconductors with metal nanoinclusions were theoretically investigated in the framework of relaxation time approximation, in which perturbation theory was used to calculate scattering probabilities analytically. Our results reveal that it is not the single scattering at interface potential barriers caused by the nanoinclusions but the synergetic scattering of electrons at ionized impurities and the interface potential barriers or wells that can produce giant scattering parameter λ (=3.3-4.7). Due to giant λ and enhanced thermopower, the estimated figure of merit ZT=3.4 at 800 K for PbTe with Pb nanoinclusions. [ABSTRACT FROM AUTHOR]

We present a linear relationship between the cohesive energies and the H/Si ratio for hydrogen-terminated Si semiconductor nanostructures based on our model analysis and first-principles calculations. The H/Si ratio is shown to be a universal predictor of the nanostructure’s energetic stability and allows easily searching of magic numbers in Si quantum dots. Our findings substantially improve the understanding of nanostructure stability and make practical the prediction of structural properties. [ABSTRACT FROM AUTHOR]

We report that the performances of blue polymer electrophosphorescent devices are crucially depending on the choice of the electron transporting material incorporated into the emissive layer. Devices with 1,3-bis[(4-tert-butylphenyl)-1,3,4-oxidiazolyl]phenylene (OXD-7) doped at ∼40 wt% into a poly(vinylcarbazole) matrix exhibited significantly higher efficiencies than those with 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), yielding maximum luminous and power efficiency values of 18.2 Cd/A and 8.8 lm/W, respectively. Time resolved photoluminescence measurements revealed a long lifetime phosphorescence component in layers with PBD, which we assign to significant triplet harvesting by this electron-transporting component. [ABSTRACT FROM AUTHOR]

By virtue of a silicon high-Q photonic crystal nanocavity, we propose and examine theoretically interactions between a stationary electron spin qubit of a semiconductor nanocrystal and a flying photon qubit. Firstly, we introduce, derive, and demonstrate the explicit conditions toward realization of a spin-photon phase gate, and propose these interactions as a generalized quantum interface for quantum information processing. Secondly, we examine single-spin-induced reflections as direct evidence of intrinsic bare and dressed modes in our coupled nanocrystal-cavity system. [ABSTRACT FROM AUTHOR]

Structured silver-capped silicon nanowires were fabricated via electroless metal deposition on a silicon wafer in an ionic silver HF solution through selective chemical etching. Their formation mechanism was explained on the basis of self-assembled localized microscopic electrochemical cell model. The metal-semiconductor composite nanostructure was found to have a strong ultraviolet-emitting property with an emission peak position at 330 nm. The intensity of the peak nonmonotonously varies with annealing temperature and time, but its position remains unchanged. Emission and excitation spectral analyses suggest that the ultraviolet emission is closely related to the existence of silver vacancy defects in silver nanocaps formed during sample fabrication. A specific vacancy density is required to produce the strong ultraviolet emission. [ABSTRACT FROM AUTHOR]

Crystalline Er2O3 thin films were epitaxially grown on Si (001) substrates. The dielectric constant of the film with an equivalent oxide thickness of 2.0 nm is 14.4. The leakage current density as small as 1.6×10-4 A/cm2 at a reversed bias voltage of -1 V has been measured. Atomically sharp Er2O3/Si interface, superior electrical properties, and good time stability of the Er2O3 thin film indicate that crystalline Er2O3 thin film can be an ideal candidate of future electronic devices. [ABSTRACT FROM AUTHOR]