Presentation Information
[1P29]Modulation of electrical conductivity and optical property of MoS2 by in-situ vacuum annealing and sulfur vapor deposition
*Takumi Yoshida1, Hideki Hamamoto1, Yasushi Ishiguro2, Kazuyuki Takai1 (1. Graduate school of Science and Engineering, Hosei University, 2. Department of Electrical and Electronic Engineering, National Defense Academy)
Monolayer molybdenum disulfide (1L-MoS2) can be easily obtained using Scotch tape method, that has a unique structure and a direct band gap, making it a promising material for device applications. However, the sulfur vacancies formed during the 1L-MoS2 preparation process and vacuum annealing for degassing not only act as electron donors but also degrade device properties. In this study, we investigated the modulation of electrical conductivity, PL, and Raman spectra of 1L-MoS2 when 1L-MoS2 was annealed in a vacuum and sulfur was vapor-deposited in situ. The hole-doping caused by sulfur vapor deposition progresses with increasing the deposition time, but gradually shows a tendency toward saturation. This suggests that the sulfur vacancies were sufficiently healed by sulfur vapor deposition ca. 4 h. Hole doping due to sulfur deposition was also observed in PL measurements, and hole doping was observed under each condition (25 °C, 200 °C), even when the sample temperature during sulfur deposition was changed.