InGaAs Quantum Dots on Cross-Hatch Patterns as a Host for Diluted Magnetic Semiconductor Medium

Optical properties of as-grown and annealed InAs quantum dots on InGaAs cross-hatch patterns

InAs quantum dots (QDs) grown on InGaAs cross-hatch pattern (CHP) by molecular beam epitaxy are characterized by photoluminescence (PL) at 20 K. In contrast to QDs grown on flat GaAs substrates, those grown on CHPs exhibit rich optical features which comprise as many as five ground-state emissions from [1-10]- and [110]-aligned QDs, two wetting layers (WLs), and the CHP. When subject to in situ...

Magnetic Semiconductor Quantum Dots

Cdo.5Mno.5S diluted magnetic semiconductor (DMS) quantum dots (QDs) of crystallite size ranging from 24 A to the bulk have been chemically synthesized using an aqueous solution precipitation method and thermal annealing. Subsequent characterization indicates that the "as prepared" material is of the cubic zinc blende structure which evolves with increasing size to the bulk hexagonal wurtzite st...

The Interplay Of Size- And Site-Dependence Of Magnetic Properties Of Diluted Magnetic Semiconductor Quantum Dots

High-temperature ferromagnetism in Ni2+-doped ZnO aggregates prepared from colloidal diluted magnetic semiconductor quantum dots.

Ferromagnetism with T(c)>350 K is observed in the diluted magnetic semiconductor Ni(2+):ZnO synthesized from solution. Whereas colloidal Ni(2+):ZnO nanocrystals are paramagnetic, their aggregation gives rise to robust ferromagnetism. The appearance of ferromagnetism is attributed to the increase in domain volumes and the generation of lattice defects upon aggregation. The unusual temperature de...

ZSM-5 Zeolite As Host Material for Semiconductor Nanoparticles

This work describes the optical and structure properties of nickel sulfide and cobalt sulfide nanoparticles in ZSM-5 zeolite. The samples were obtained by sulfidation of the Ni2+ and Co2+ ion-exchange ZSM-5 zeolites in a Na2S solution at room temperature. The optical properties of the samples were studied by UV-visible spectroscopy. Their crystalline structure and morphology were studied by X-r...