The large-scale growth of semiconducting thin films forms the basis of modern electronics and optoelectronics. A decrease in film thickness to the ultimate limit of the atomic, sub-nanometre length scale, a difficult limit for traditional semiconductors (such as Si and GaAs), would bring wide benefits for applications in ultrathin and flexible electronics, photovoltaics and display technology. For this, transition-metal dichalcogenides (TMDs), which can form stable three-atom-thick monolayers, provide ideal semiconducting materials with high electrical carrier mobility, and their large-scale growth on insulating substrates would enable the batch fabrication of atomically thin high-performance transistors and photodetectors on a technologically relevant scale without film transfer. In addition, their unique electronic band structures provide novel ways of enhancing the functionalities of such devices, including the large excitonic effect, bandgap modulation, indirect-to-direct bandgap transition, piezoelectricity and valleytronics. However, the large-scale growth of monolayer TMD films with spatial homogeneity and high electrical performance remains an unsolved challenge. Here we report the preparation of high-mobility 4-inch wafer-scale films of monolayer molybdenum disulphide (MoS2) and tungsten disulphide, grown directly on insulating SiO2 substrates, with excellent spatial homogeneity over the entire films. They are grown with a newly developed, metal-organic chemical vapour deposition technique, and show high electrical performance, including an electron mobility of 30 cm(2) V(-1) s(-1) at room temperature and 114 cm(2) V(-1) s(-1) at 90 K for MoS2, with little dependence on position or channel length. With the use of these films we successfully demonstrate the wafer-scale batch fabrication of high-performance monolayer MoS2 field-effect transistors with a 99% device yield and the multi-level fabrication of vertically stacked transistor devices for three-dimensional circuitry. Our work is a step towards the realization of atomically thin integrated circuitry.

Epitaxy forms the basis of modern electronics and optoelectronics. We report coherent atomically thin superlattices in which different transition metal dichalcogenide monolayers-despite large lattice mismatches-are repeated and laterally integrated without dislocations within the monolayer plane. Grown by an omnidirectional epitaxy, these superlattices display fully matched lattice constants across heterointerfaces while maintaining an isotropic lattice structure and triangular symmetry. This strong epitaxial strain is precisely engineered via the nanoscale supercell dimensions, thereby enabling broad tuning of the optical properties and producing photoluminescence peak shifts as large as 250 millielectron volts. We present theoretical models to explain this coherent growth and the energetic interplay governing the ripple formation in these strained monolayers. Such coherent superlattices provide building blocks with targeted functionalities at the atomically thin limit.

Twisted bilayer graphene ( t BLG) is a metallic material with two degenerate van Hove singularity transitions that can rehybridize to form interlayer exciton states. Here we report photoluminescence (PL) emission from t BLG after resonant 2-photon excitation, which tunes with the interlayer stacking angle, θ . We spatially image individual t BLG domains at room-temperature and show a five-fold resonant PL-enhancement over the background hot-electron emission. Prior theory predicts that interlayer orbitals mix to create 2-photon-accessible strongly-bound (~0.7 eV) exciton and continuum-edge states, which we observe as two spectral peaks in both PL excitation and excited-state absorption spectra. This peak splitting provides independent estimates of the exciton binding energy which scales from 0.5–0.7 eV with θ = 7.5° to 16.5°. A predicted vanishing exciton-continuum coupling strength helps explain both the weak resonant PL and the slower 1 ps −1 exciton relaxation rate observed. This hybrid metal-exciton behavior electron thermalization and PL emission are tunable with stacking angle for potential enhancements in optoelectronic and fast-photosensing graphene-based applications.

Gastric cancer (GC) is one of the most common human malignancies due to its invasiveness and metastasis. 5-Fu is a widely applied chemotherapeutic agent against GC. Although 5-Fu therapy has achieved improvements in GC treatment, a large fraction of patients developed drug resistance which significantly limited its clinical applications. Recent studies revealed the pivotal roles of long noncoding RNAs (lncRNAs) in tumorigenesis and progressions of various tumors, including GC. However, the biological roles and molecular mechanisms of lncRNA HAGLR in GC remain unclear. Here, we report HAGLR was upregulated in both GC tissues and cell lines. In addition, HAGLR was associated with a poorly survival rate of GC patients. Blocking HAGLR inhibited GC cells proliferation and sensitized GC cells to 5-Fu. Bioinformatical analysis and luciferase assay demonstrated that HAGLR sponged microRNA (miR)-338-3p, which functions as a tumor suppressor in GC to downregulate its expressions. Moreover, from the established 5-Fu resistant GC cell line (HGC27 5-Fu R), we detected significantly elevated HAGLR, downregulated miR-338-3p, and glucose metabolism compared with parental HGC27 cells. We identified lactate dehydrogenase-A (LDHA), a glucose metabolism key enzyme, was the direct target of miR-338-3p in GC cells.Rescue experiments demonstrated that restoration of miR-338-3p in HAGLRoverexpressing HGC27 5-Fu R cells successfully overrode the HAGLR-promoted 5-Fu resistance through targeting LDHA. Taken together, this study revealed essential roles and molecular mechanisms for the HAGLR-mediated 5-Fu resistance in GC, contributing to the development of new noncoding RNA-based therapeutic strategies against chemoresistant GC.

A family of layered lanthanide (Pr, Nd, Sm, Eu, and Gd) hydroxide nanowires (NWs) has been synthesized via a hydrothermal route. These NWs are ∼8 nm in diameter and a few micrometres in length. The obtained Eu- and Gd-based layered hydroxide NWs consist of layered structure with two interlayer spacings. The effects of hydrothermal temperature and time on the transition of the layered structure were investigated. Photoluminescence of the Eu-based layered hydroxide NWs was also studied. These layered lanthanide hydroxide NWs combine the advantages of lanthanide and layered hydroxides, which will expand the inorganic layered materials and can be expected to be used as building blocks for further fabrication of functional nanostructures.