Layer-dependent nonlinear optical properties and stability of non-centrosymmetric modification in few-layer GaSe sheets.

Gallium selenide, an important second-order nonlinear semiconductor, has received much scientific interest. However, the nonlinear properties in its two-dimensional (2D) form are still unknown. A strong second harmonic generation (SHG) in bilayer and multilayer GaSe sheets is reported.

Exceptional tunability of band energy in a compressively strained trilayer MoS2 sheet.

Tuning band energies of semiconductors through strain engineering can significantly enhance their electronic, photonic, and spintronic performances. Although low-dimensional nanostructures are relatively flexible, the reported tunability of the band gap is within 100 meV per 1% strain. It is also challenging to control strains in atomically thin semiconductors precisely and monitor the optical and phonon properties simultaneously.

n- and p-Type modulation of ZnO nanomesh coated graphene field effect transistors.

Periodic zinc oxide (ZnO) nanomeshes of different thicknesses were deposited on single-layer graphene to form back-gated field effect transistors (GFETs). The GFETs exhibit tunable electronic properties, featuring n- and p-type characteristics by merely controlling the thickness of the ZnO nanomesh layer. Furthermore, the effect of thermal strain on the GFETs from the substrate is suppressed by the ZnO nanomesh, which improves the thermal stability of the GFETs.