Yu Hao, Yan Hui, Li Heng, Li Zhuocheng, Bai Yanliu, Zhu Hao, Yin Shougen
Tianjin Key Laboratory of Photoelectric Materials and Devices, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, P. R. China.
Key Laboratory of Display Materials and Photoelectric Devices, National Demonstration Center for Experimental Function Materials Education, Tianjin University of Technology, Ministry of Education, Tianjin 300384, P. R. China.
ACS Appl Mater Interfaces. 2021 Sep 22;13(37):44693-44702. doi: 10.1021/acsami.1c09176. Epub 2021 Sep 8.
The band gap engineering of two-dimensional (2D) transition metal dichacogenides (TMDs) could significantly broaden their applications, especially in electronics and optoelectronics. Alloying is a more effective approach to synthesize 2D ternary TMD materials with tunable bandgaps by regulating the compositions. Whether the alloying could induce memory effects is of interest as a scientific problem and worthy to be studied. A thermal evaporation-assisted chemical vapor deposition (CVD) method was proposed to grow millimeter size gradient alloyed monolayer MoWS. This method reveals a promising and universal methodology for the development of gradient alloyed TMDs because of the precise controlling of each precursor. The synthesized MoWS monolayer crystal has a gradient composition with ranging from 0.1 to 1. The W and Mo atoms homogeneously alloyed with random distribution in the MoWS monolayer. As reported, the deep energy levels induced by sulfur vacancies can be effectively suppressed to shallow energy levels by alloying TMDs. The series distribution of the shallow energy levels in the band of the graded alloy semiconductor can act as multiple charge trapping states, which leads to obvious memory effects in the device. These results present a new opportunity for memory devices and related applications.
二维（2D）过渡金属二硫属化物（TMDs）的带隙工程可以显著拓宽其应用范围，特别是在电子学和光电子学领域。合金化是一种通过调节成分来合成具有可调带隙的二维三元TMD材料的更有效方法。合金化是否会引起记忆效应作为一个科学问题备受关注且值得研究。提出了一种热蒸发辅助化学气相沉积（CVD）方法来生长毫米尺寸的梯度合金化单层MoWS。由于对每种前驱体的精确控制，该方法为梯度合金化TMDs的开发揭示了一种有前景且通用的方法。合成的MoWS单层晶体具有范围从0.1到1的梯度组成。W和Mo原子在MoWS单层中均匀合金化且随机分布。如所报道的，通过TMDs合金化可以有效地将由硫空位诱导的深能级抑制为浅能级。梯度合金半导体能带中浅能级的系列分布可以充当多个电荷俘获态，这导致器件中出现明显的记忆效应。这些结果为记忆器件及相关应用提供了新机遇。
