Investigation of Defect InP(001) Surface by Low Energy Ion Scаttering Spectroscopy

In this paper presents the computer simulation results on the investigations of the ion scattering processe on the defect InP(001)<110>,<ī10> surface under low-energy grazing ion bombardment have been presented. The peculiarities trajectories of the scattered ions from surface defect, atomic chain and semichannel have been investigated by computer simulation. It was found some trajectories nearby surface atomic chain which have loop shape and a line form. At grazing ion incidence, from a correlation of the experimental and calculated energy distributions of the scattered particles, one may determine a spatial extension of the missing atom on the monocrystal surface damaged by the ion bombardment.

High-quantum yield alloy-typed core/shell CdSeZnS/ZnS quantum dots for bio-applications

Background Quantum dots (QDs) have been used as fluorophores in various imaging fields owing to their strong fluorescent intensity, high quantum yield (QY), and narrow emission bandwidth. However, the application of QDs to bio-imaging is limited because the QY of QDs decreases substantially during the surface modification step for bio-application. Results In this study, we fabricated alloy-typed core/shell CdSeZnS/ZnS quantum dots (alloy QDs) that showed higher quantum yield and stability during the surface modification for hydrophilization compared with conventional CdSe/CdS/ZnS multilayer quantum dots (MQDs). The structure of the alloy QDs was confirmed using time-of-flight medium-energy ion scattering spectroscopy. The alloy QDs exhibited strong fluorescence and a high QY of 98.0%. After hydrophilic surface modification, the alloy QDs exhibited a QY of 84.7%, which is 1.5 times higher than that of MQDs. The QY was 77.8% after the alloy QDs were conjugated with folic acid (FA). Alloy QDs and MQDs, after conjugation with FA, were successfully used for targeting human KB cells. The alloy QDs exhibited a stronger fluorescence signal than MQD; these signals were retained in the popliteal lymph node area for 24 h. Conclusion The alloy QDs maintained a higher QY in hydrophilization for biological applications than MQDs. And also, alloy QDs showed the potential as nanoprobes for highly sensitive bioimaging analysis. Graphical Abstract