The exfoliation and identification of the two-dimensional (2D) single atomic layer of carbon have opened the opportunity to explore graphene and related 2D materials due to their unique properties. 2D materials are regarded as one of the most exciting solutions for next generation electronics and optoelectronics in the technological evolution of semiconductor technology. In this review, we focus on the core concept of "structure-property relationships" to explain the state-of-the-art of 2D materials and summarize the unique electrical and light-matter interaction properties in 2D materials. Based on this, we discuss and analyze the structural properties of 2D materials, such as defects and dopants, the number of layers, composition, phase, strain, and other structural characteristics, which could significantly alter the properties of 2D materials and hence affect the performance of semiconductor devices. In particular, the building blocks principles and potential electronic and optoelectronic applications based on 2D materials are explained and illustrated. Indeed, 2D materials and related heterostructures offer the promise for challenging the existing technologies and providing the chance to have social impact. More efforts are expected to propel this exciting field forward.

Metamaterial assisted terahertz (THz) label-free bio-sensing has promising applications. However, the sensitive THz detection of highly absorptive liquid samples remains challenging. Here, we present a novel multi-microfluidic-channel metamaterial biosensor (MMCMMB) for highly sensitive THz sensing of small volume liquid samples. The multi-channels are set mostly in the strong electric field enhancement area of the metamaterial, which significantly decreases the liquid amount and enhances interaction between the sensing targets and the THz wave (thus increasing the sensitivity). The sensing results of isopropyl alcohol (IPA)-water mixtures and bovine serum albumin (BSA) solutions based on the bow-tie array metamaterial with multi-channels demonstrate the effectiveness of this proposed design and the great potential in THz bio-sensing. This design has the advantages of being highly sensitive, label-free, cost-effective, easy to operate and only needing a tiny liquid volume. Thus our device provides a robust route for metamaterial assisted THz label-free bio-sensing of liquid-based substances. IndexTerms-Terahertz spectroscopy, biomedical spectroscopy, metamaterial, microfluidic.

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Transition metal dichalcogenides (TMDCs) have recently attracted growing attention in the fields of dielectric nanophotonics because of their high refractive index and excitonic resonances. Despite the recent realizations of Mie resonances by patterning exfoliated TMDC flakes, it is still challenging to achieve large-scale TMDC-based photonic structures with a controllable thickness. Here, we report a bulk MoS2 metaphotonic platform realized by a chemical vapor deposition (CVD) bottom-up method, supporting both pronounced dielectric optical modes and self-coupled polaritons. Magnetic surface lattice resonances (M-SLRs) and their energy-momentum dispersions are demonstrated in 1D MoS2 gratings. Anticrossing behaviors with Rabi splitting up to 170 meV are observed when the M-SLRs are hybridized with the excitons in multilayer MoS2. In addition, distinct Mie modes and anapole-exciton polaritons are also experimentally demonstrated in 2D MoS2 disk arrays. We believe that the CVD bottom-up method would open up many possibilities to achieve large-scale TMDC-based photonic devices and enrich the toolbox of engineering exciton-photon interactions in TMDCs.