Chemical vapor deposition (CVD)-grown monolayer (ML) molybdenum disulfide (MoS2) is a promising material for next-generation integrated electronic systems due to its capability of high-throughput synthesis and compatibility with wafer-scale fabrication. Several studies have described the importance of Schottky barriers in analyzing the transport properties and electrical characteristics of MoS2 field-effect-transistors (FETs) with metal contacts. However, the analysis is typically limited to single devices constructed from exfoliated flakes and should be verified for large-area fabrication methods. In this paper, CVD-grown ML MoS2 was utilized to fabricate large-area (1 cm x 1 cm) FET arrays. Two different types of metal contacts (i.e., Cr/Au and Ti/Au) were used to analyze the temperature-dependent electrical characteristics of ML MoS2 FETs and their corresponding Schottky barrier characteristics. Statistical analysis provides new insight about the properties of metal contacts on CVD-grown MoS2 compared to exfoliated samples. Reduced Schottky barrier heights (SBH) are obtained compared to exfoliated flakes, attributed to a defect-induced enhancement in metallization of CVD-grown samples. Moreover, the dependence of SBH on metal work function indicates a reduction in Fermi level pinning (FLP) compared to exfoliated flakes, moving towards the Schottky-Mott limit. Optical characterization reveals higher defect concentrations in CVD-grown samples supporting a defect-induced metallization enhancement effect consistent with the electrical SBH experiments.

This paper provides comprehensive experimental analysis relating to improvements in the two-dimensional (2D) p-type metal–oxide–semiconductor (PMOS) field effect transistors (FETs) by pure van der Waals (vdW) contacts on few-layer tungsten diselenide (WSe2) with high-k metal gate (HKMG) stacks. Our analysis shows that standard metallization techniques (e.g., e-beam evaporation at moderate pressure ~ 10–5 torr) results in significant Fermi-level pinning, but Schottky barrier heights (SBH) remain small (< 100 meV) when using high work function metals (e.g., Pt or Pd). Temperature-dependent analysis uncovers a more dominant contribution to contact resistance from the channel access region and confirms significant improvement through less damaging metallization techniques (i.e., reduced scattering) combined with strongly scaled HKMG stacks (enhanced carrier density). A clean contact/channel interface is achieved through high-vacuum evaporation and temperature-controlled stepped deposition providing large improvements in contact resistance. Our study reports low contact resistance of 5.7 kΩ-µm, with on-state currents of ~ 97 µA/µm and subthreshold swing of ~ 140 mV/dec in FETs with channel lengths of 400 nm. Furthermore, theoretical analysis using a Landauer transport ballistic model for WSe2 SB-FETs elucidates the prospects of nanoscale 2D PMOS FETs indicating high-performance (excellent on-state current vs subthreshold swing benchmarks) towards the ultimate CMOS scaling limit.

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This paper aims to propose an effective method to carry out Chinese character education for children through the analyzation and research with the feasibility, in order to promote the effects of Chinese character education and further promote their psychological development and inheritance of traditional Chinese culture. With the method of literature review and object of children's Chinese character teaching methods, this paper makes a further research with the application of related methods and concludes a more practical Chinese character teaching methods for children by analyzing its significance and possibility. Namely, the method of word source literacy, associative thinking, literacy sensitive period, division to integration, introduction of traditional stories, scene creation, game literacy and image literacy. It is innovative that this paper connects the former theoretical research and real teaching to conclude the Chinese character teaching methods corresponding with children's psychological development characteristics. 1. Definition Of Related Concepts 1.1 Chinese characters Chinese characters are the writing system for recording language and the most significant auxiliary communication tool. The simplified Chinese characters used now mainly are involved in this paper[1]. 1.2 Chinese character education The purpose of Chinese character education is to know the shape, phonetic and meaning of Chinese characters and understand their bearing cultural content. In addition, it involves training good reading habits[1]. 1.3 Education methods Education methods refer to the strategic approaches to realize the education thought under the guidance of certain education ideas, which are the reflection and concrete expression of objective laws and principles of education. 2. The Significance of Teaching Children Chinese Characters 2.1 Helpful to improve children's perception abilities The first step for children to understand and explore the world is sensory perception, which is the foundation of psychological activity development. Children will have the shape perception soon after the birth, so the Chinese characters presented by teachers are like a picture for children. The explanation and introducing the background of Chinese characters stimulate children's sense of vision and hearing so as to promote the development of their perception abilities. 2.2 Helpful to improve children's image thinking and abstract thinking abilities Children may gradually form their thinking about two years old, which is realized by means of action and language. It is a superior psychological activity of human being. Chinese character is one kind of abstract symbol system with the characteristics of pictographic understanding. It is the unification of image and abstraction. Therefore, children's image and abstract thinking abilities will be improved in the process of learning Chinese characters. For example, the word of "dry" means that the fields are dry every day by the great sun.