irect Observation of Semiconductor-Metal Phase Transition in Bilayer Tungsten Diselenide Induced by Potassium Surface Functionalization
irect Observation of Semiconductor-Metal Phase Transition in Bilayer Tungsten Diselenide Induced by Potassium Surface Functionalization
复制标题
钾表面功能化诱导的双层二硒化钨中半导体-金属相变的直接观察
DOI：
10.1021/acsnano.8b00398
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发表时间：
2018
期刊：
影响因子：
17.1
通讯作者：
Chen Wei
中科院分区：
文献类型：
--
作者：
Lei B;Pan YY;HU ZH;Xiang D;Zheng Y;Guo R;han C;Wang LH;Lu J;Yang L;Chen Wei
结构决定材料的性能，因此，可控相变对于探索奇异物理和制造器件是非常必要的。我们直接观察到钾(K)表面功能化的双层二硒化钨(WSe_2)中可控的半导体-金属相变。通过场效应管、X射线光电子能谱、紫外光电子能谱测量和第一性原理计算，我们确定了K原子的电子掺杂驱动了双层WSe2从2H相半导体到1T‘相金属。2H和1T‘相的电子结构和能量取向较好地解释了相变机理。这一解释一般可用于理解二维(2D)结构中掺杂诱导的相变。最后，电子结构和电导的巨大变化使得这种可控的半导体-金属相变成为基于2D半导体的电子和光电子器件感兴趣的问题。
Structures determine properties of materials, and controllable phase transitions are, therefore, highly desirable for exploring exotic physics and fabricating devices. We report a direct observation of a controllable semiconductor–metal phase transition in bilayer tungsten diselenide (WSe2) with potassium (K) surface functionalization. Through the integration ofin situfield-effect transistors, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy measurements, and first-principles calculations, we identify that the electron doping from K adatoms drives bilayer WSe2from a 2H phase semiconductor to a 1T′ phase metal. The phase transition mechanism is satisfactorily explained by the electronic structures and energy alignment of the 2H and 1T′ phases. This explanation can be generally applied to understand doping-induced phase transitions in two-dimensional (2D) structures. Finally, the associated dramatic changes of electronic structures and electrical conductance make this controllable semiconductor–metal phase transition of interest for 2D semiconductor-based electronic and optoelectronic devices.