Quasi-homogenous photocatalysis of quantum-sized Fe-doped TiO2 in optically transparent aqueous dispersions

In this study, the preparation of anatase TiO2 nanocrystals via a facile non-aqueous sol–gel route and their characterization are reported. The 3–4 nm particles are readily dispersable in aqueous media and show excellent photoreactivity in terms of rhodamine B degradation. The catalytic performance can be further increased considerably by doping with iron and UV-light irradiation as a pre-treatment. The effect of surface ligands (blocked adsorption sites, surface defects etc.) on the photoreactivity was thoroughly probed using thermogravimetric analysis combined with mass spectrometry. Photoelectrochemical characterization of thin-film electrodes made from the same TiO2 nanocrystals showed the opposite trend to the catalytic experiments, that is, a strong decrease in photocurrent and quantum efficiency upon doping due to introduction of shallow defect states.

Effects of Yttrium Doping on a-IGZO Thin Films for Use as a Channel Layer in Thin-Film Transistors

Amorphous In−Ga−Zn−O (a-IGZO) has been studied as a channel layer in thin-film transistors (TFTs). To improve the bias-induced instability of a-IGZO TFTs, we introduced yttrium with high bond enthalpy by magnetron co-sputtering system. The Y-doped a-IGZO (a-IGZO:Y) films show relatively lower carrier concentration and higher Hall mobility, which is due to the suppression of oxygen vacancies caused by Y doping. The a-IGZO:Y showed a relatively higher transmittance in the visible light region compared to non-doped IGZO, which could be due to the decrease of shallow defect levels caused by oxygen vacancy in the band gap. The a-IGZO without Y doping showed dramatic changes in electrical properties as times progressed (over 240 h); however, the a-IGZO:Y showed no significant changes. The a-IGZO:Y TFTs demonstrated a more stable driving mode as exhibited in the positive gate bias stress test even though the values of VTH and SS were slightly degraded.

A self-doping strategy to improve the photoelectrochemical performance of Cu2ZnSnS4 nanocrystal films for water splitting

A self-doped CZTS photocathode showed improved PEC activity due to the conduction band shift and the formation of a shallow defect level.

A Discussion of Dielectric Film Deformation by E-Beam Energy

A recently developed technique known as Electron Beam Induced Resistance Change (EBIRCH) equipped with a scanning electron microscope (SEM) utilizes a constant electron beam (e-beam) voltage across or current through the defect of interest and amplifies its resistance variation. In this study, EBIRCH is applied for a 3D NAND structure device fault isolation but suffered from nearby dielectric film deformation. The characterization of such dielectric deformation and the possible mechanisms of e-beam induced damage are discussed. As well, a threshold condition to avoid from triggering the occurrence of dielectric damage is presented for shallow defect analysis in EBIRCH application.