Phase-engineered two-dimensional materials toward 2D/3D hybrid heterostructures and its functional applications

Yu-Lun Chueh^1*

¹Materials Science and Engineering, ​National Tsing-Hua University, ​ Hsinchu, Taiwan

* Presenter:Yu-Lun Chueh, email:ylchueh@mx.nthu.edu.tw

2D materials have attracted much attention because of frontier electronic materials due to its superior electronic transport properties and mechanical flexibility in the future, making it a potential material for high performance and wearable electronics. Graphene is a typical 2D materials with high carrier mobility; however, it still cannot be applied in transistor due to the lack of bandgap. A new type of 2D semiconducting materials called transition metal dichalcogenides (TMDCs), which are the layered structure with the strong in-plane bonding and weak out-of-plane interactions similar to graphite, have been intensively studied. Recent studies have predicted exceptional physical properties upon reduced dimensionality attracting lots of attention due to the versatile physical chemical behaviors. Nevertheless, the synthesis and the study of the fundamental physical properties of TMDs are still in the early stages. The lack of a large-area and reliable synthesis method restrict exploring all the potential applications of the TMDs. Chemical vapor deposition (CVD) is a traditional approach for the growth of TMDs; nevertheless, the high growth temperature is a major drawback for its to be applied in flexible electronics. In this talk, an inductively coupled plasma (ICP) was used to synthesize Transition Metal Dichalcogenides (TMDs) through a plasma-assisted selenization process of metal oxide (MOx) at a low temperature, as low as 250 °C. Compared to other CVD processes the use of ICP facilitates the decomposition of the precursors at lower temperatures; therefore, the temperature required for the formation of TMDs can be drastically reduced. In addition, the phases from 1T to 2H are found to be different at different selenized temperatures. Different TMDs, including WSe2, MoSe2, PtSe2 and SnSe2 were chosen as model material systems. Furthermore, by controlling different H2/N2 ratios, hybrid WOx/WSe2 films can be formed as shown by TEM and confirmed by XPS. The applications o including (1) water splitting, (2) gas sensors, (3) photodetectors, (3) anode materials in the battery will be reported.⅔

Keywords: two-dimensional materials, 3D hybrid heterostructures, water splitting, gas sensors, photodetectors