High on/off ratio field effect transistors based on exfoliated crystalline SnS2 nano-membranes.

We report the implementation of field effect transistors based on exfoliated nano-membranes of a layered two-dimensional semiconductor SnS(2), which exhibit an on/off ratio exceeding 2 × 10(6) and a carrier mobility of ∼1 cm(2) V(-1) s(-1). The results demonstrate the great potential of SnS(2), a layered semiconductor with finite band gap, as the building block for future nanoelectronic applications complementary to graphene-based materials with zero or small band gaps.

Observation of multiple superconducting gaps in Fe₁+yTe₁-xSex via a nanoscale approach to point-contact spectroscopy.

We report a novel experimental approach to point-contact Andreev reflection spectroscopy with diagnostic capability via a unique design for nanoscale normal metal/superconductor devices with excellent thermomechanical stability, and have employed this method to unveil the existence of two superconducting energy gaps in iron chalcogenide Fe(1+y)Te(1-x)Se(x), which is crucial for understanding its pairing mechanism. This work opens up new opportunities to study gap structures in superconductors and elemental excitations in solids.

AB-stacked multilayer graphene synthesized via chemical vapor deposition: a characterization by hot carrier transport.

We report the synthesis of AB-stacked multilayer graphene via ambient pressure chemical vapor deposition on Cu foils and demonstrate a method to construct suspended multilayer graphene devices. In four-terminal geometry, such devices were characterized by hot carrier transport at temperatures down to 240 mK and in magnetic fields up to 14 T. The differential conductance (dI/dV) shows a characteristic dip at longitudinal voltage bias V = 0 at low temperatures, indicating the presence of hot electron effect due to a weak electron-phonon coupling.