Phase Transition in Two-Dimensional MoS2 Layer Probed by Synchrotron Nano-beam for Thin-film Transistors and Memtransistors

Mayur Chaudhary^1*, Li-Chyong Chen², Kuei-Hsien Chen², Peter V. Sushko³, Chih-Hao Lee⁴, Ya-Ping Chiu⁵, Yu-Lun Chueh¹

¹Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan
²Center for Condensed Matter Science, National Taiwan University, Taipei, Taiwan
³Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Washingtom, USA
⁴Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
⁵Department of Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Mayur Chaudhary, email:chaudharymayur87@gmail.com

Transition metal dichalcogenides (TMDs) are the emerging class of two-dimensional (2D) materials with
potential to develop next-generation electronic and optoelectronic nanodevices. The mobility enhancement by defect
engineering offers an attractive solution of using layered-semiconductors based transistors in low-power switching
applications. In this work, we report a novel approach to reduce the channel resistance by inducing 2H to 1T phase
transition in MoS2 layer using synchrotron nano-beam. The synchrotron nano-beam is adopted to induce structural
transition to achieve 1T domain of few nanometers in 2D-MoS2. The precise phase engineering triggered by nano-beam,
allowing the realization of field-effect transistors (FET) exhibiting 2X improvement in mobility, high on/off ratio (~108)
and near-ideal subthreshold swing (~88 mV per decade). The validity of phase engineering is further extended for its
application as a memory device exhibiting gate tunable conduction modulation. The device can achieve high resistance
ratio (>102 at gate bias of 5 V) and retain its state for 100 cycle.

Keywords: Semiconductor, defect engineering, transition metal dichalcogenide