We report the synthesis of large-area monolayer MoSe ₂ films extended up to a millimeter scale on SiO ₂ /Si substrates by atmospheric pressure chemical vapor deposition (CVD).

The authors investigated the field emission from vertically well-aligned zinc oxide (ZnO) nanoneedles grown on the $\mathrm{Au}∕\mathrm{Ti}∕n\text{-}\mathrm{Si}$ (100) substrate using metal organic chemical vapor deposition. The turn-on field of ZnO nanoneedles was about $0.85\mathrm{V}∕\mu \mathrm{m}$ at the current density of $0.1\mu \mathrm{A}∕{\mathrm{cm}}^2$ , and the emission current density of $1\mathrm{mA}∕{\mathrm{cm}}^2$ was achieved at the applied electric field of $5.0\mathrm{V}∕\mu \mathrm{m}$ . The low turn-on field of the ZnO nanoneedles was attributed to very sharp tip morphology, and the high emission current density was mainly caused by the formation of the stable Ohmic contact between the ZnO nanoneedles and Au film.

We investigated the dependence of electron mobility on the thickness of MoS₂ nanosheets by fabricating bottom-gate single and few-layer MoS₂ thin-film transistors with SiO₂ gate dielectrics and Au electrodes. All the fabricated MoS₂ transistors showed on/off-current ratio of ∼10⁷ and saturated output characteristics without high-k capping layers. As the MoS₂ thickness increased from 1 to 6 layers, the field-effect mobility of the fabricated MoS₂ transistors increased from ∼10 to ∼18 cm²V⁻¹s⁻¹. The increased subthreshold swing of the fabricated transistors with MoS₂ thickness suggests that the increase of MoS₂ mobility with thickness may be related to the dependence of the contact resistance and the dielectric constant of MoS₂ layer on its thickness.

In the case of colossal magnetoresistance in the perovskite manganites, “double exchange” mediated by the itinerant spins is believed to play a key role in the ferromagnetism. In contrast, the conventional “Heisenberg” interaction, i.e., direct (unmediated) interaction between the localized spins produced by the proton irradiation, is identified as the origin of proton irradiation-induced ferromagnetism in graphite.