PtS2的表面相工程：单晶PtS2-非晶PtSx-单晶Pt

PtS₂的表面相工程：单晶PtS₂-非晶PtS_x-单晶Pt

袁墩栋，何勇民，赵晓续，朱  超，孙立涛^*

（1.东南大学—FEI纳皮米中心，MEMS教育部重点实验室，东南大学电子科学与工程学院，江苏 南京  210096；2. 湖南大学 化学化工学院，湖南 长沙 410082；3. 北京大学 材料科学与工程学院，北京 100871)

摘  要 本文利用原子级扫描透射电子显微术（STEM）研究了PtS₂在连续Ar等离子体作用下其表面S原子不断缺失并导致相转变的过程。实验发现随着S原子占比的减小，层状1T相PtS₂以逐层非晶化的方式转变为无定形非晶相PtS_x（x<2），并且基于径向分布函数（RDF）分析定量提取了最邻近Pt-Pt、Pt-S、S-S原子对的分布概率。随着S原子占比的继续减小，表面非晶相PtS_x最终转变为单晶Pt，结合电子能量损失谱（EELS）与STEM原子序数衬度图像分析表明，Pt原子以（111）面心立方密堆的方式堆垛，形成少层甚至单层Pt晶畴。

关键词 STEM；单层非晶PtS_x；Pt单晶；相工程

中图分类号：TG115. 21⁺ 5. 3；O649.2；O647.11     文献识别码：A    doi:10.3969/j.issn.1000-6281.2023.06.003

Surface phase engineering of PtS₂: monocrystal PtS₂ – amorphous PtS_x– monocrystal Pt

YUAN Dun-dong¹, HE Yong-min², ZHAO Xiao-xu³, ZHU Chao¹, SUN Li-tao^1*

(1. SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Southeast University, Nanjing Jiangsu 210096, ；2. College of Chemistry and Chemical Engineering, Hunan University, Changsha Hunan 410082；3. School of Materials Science and Engineering, Peking University, Beijing 100871, China)

Abstract  In this paper, the continuous loss of S atoms and the resulting phase transitions of PtS₂ under the process of Ar plasma is investigated by atomic-scale scanning transmission electron microscopy (STEM). Layered 1T phase PtS₂ transforms into amorphous phase PtS_x (x < 2) in a layer-by-layer amorphization manner as the proportion of S atoms decreases. The distribution probability of the most proximal Pt-Pt, Pt-S, S-S atom pairs are quantitatively extracted via the radial distribution function (RDF) analysis. As the proportion of S atoms further decrease, the surface amorphous PtS_x eventually transforms into Pt monocrystals. By combining electron energy loss spectroscopy (EELS) and STEM atomic number contrast image analysis, it is shown that Pt atoms are stacked in a (111) face-centered cubic close-packed manner to form few-layer or even monolayer Pt crystal domains.

Keywords  STEM; monolayer amorphous PtS_x; Pt monocrystal; phase engineering

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