First time: Science Cites Journal of Semiconductors
Since the first discovery of graphene in 2004 by A. GEIM and K. NOVOSELOV from UK, two-dimensional (2D) atomic crystalsincluding graphene, transition metal dichalcogenides (TMDs) and monoatomic buckled crystals (termed as Xenes, such as black phosphorene, silicene, germanene), with intralayer covalent bonding and interlayer van der Waals (vdW) interaction, have emerged as the frontier in the field of materials science. 2D materials led the rapid development of technologies of (opto)electronics, information and energy in the post-Moore era due to their appealing characteristics. A. GEIM and K. NOVOSELOVHAVE thus won the 2010 Nobel Prize in Physics by their important discoveries. Comparing with traditional Si- and InGaAs-based semiconductors, 2D materials possess the advantages such as high mobility, strong light-matter interaction, CMOS compatibility, low cost, high transparency and flexibility [1-4], which can provide promising platforms for new generation of wearable, highly dense and intelligent optoelectronic integrated circuits.
The researchers in China have also carried out forward-looking fundamental and applied research works on 2D materials. As a well-known leading journal in the field of semiconductors, the Journal of Semiconductors has been tracking the latest developments in this field, and invited Prof. Jingbo LI and Prof. Xinran WANG, as guest editors to organize a special issue entitled "2D Materials and Devices". Prof. Jingbo LI’s group is also one of the top research groups in China to develop 2D materials and devices, and has received extensive attentions from the international academic community. The members of the group, Dr. Nengjie HUO and Dr. Yujue YANG, published an original research paper entitled “Optoelectronics based on 2D TMDs and heterostructures” in the Journal of Semiconductors on March 2017 . This works ystematically demonstratesthe materials growth methods, thickness-dependent optical properties and high-performance optoelectronic devices (including transistors, photodetectors and photovoltaic cells) based on the self-developed 2D TMDs and their heterojunctions. The research work has played a certain role in promoting and guiding the development of 2D semiconductor technologies. In particular, they also studied the important effects and intrinsic mechanisms of the interlayer coupling and quantum confinement effects on phonon modes and band structures. It is found that single-layer TMDs have direct band gap structure and show excellent fluorescence properties (Figure 1).
Figure 1 (a) PL spectral of monolayer and bilayer WS2. The inset is schematic diagram of atomic structures of TMDs. (b) PL spectral of WSe2 with different layers.
Recently, Prof. Jeehwan KIM from the Massachusetts Institute of Technology (MIT) published a paper entitled "Controlled crack propagation for atomic precision handling of wafer-scale two-dimensional materials" on Science November 2018 . They developed a layer-resolved splitting (LRS) technique that can be universally applied to produce 2D material monolayers at the wafer scale, which is a stepping stone for commercialization of 2D material-based devices. It is worth noting that the Science paper cited the above-mentioned Journal of Semiconductors paper in two paragraphs. They adopted the experimental results reported by the Journal of Semiconductors (i.e. the direct band gap of single-layer WS2 of ~1.99 eV and strong fluorescence properties (Fig. 1a)) as one of the important evidences for their successful preparation of a single layer of WS2. The two paragraphs in Science are: "Successful isolation of the WS2 monolayer was confirmed by the substantial enhancement of the peak intensity of the PL spectra (Fig. 2D) at its direct gap of 1.99 eV, as compared with the weak and wide PL characteristic of a thick WS2 layer at its indirect gap of 1.97 eV" and "Wafer-scale monolayer thickness was also confirmed by mapping the PL peak position where peaks are all concentrated at its direct gap of 1.99 eV (Fig. S7)".
This is the first time that the world's top journal Science and the world's top university MIT cited the original paper from Journal of Semiconductors, which shows the original innovation ability of Chinese researchers in the field of 2D materials. And also imply thatthe influence of Journal of Semiconductorsin international academics is becoming more and more important.
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