MRS Meetings and Events

 

NM01.06.02 2022 MRS Spring Meeting

Defect Emission in Two-Dimensional Transition Metal Dichalcogenides

When and Where

May 9, 2022
2:00pm - 2:15pm

Hawai'i Convention Center, Level 3, 311

Presenter

Co-Author(s)

Yan Wang1,Yiru Zhu1,Soumya Sarkar1,Juhwan Lim1,Jung-In Lee1,Robert Hoye2,Manish Chhowalla1

University of Cambridge1,Imperial College London2

Abstract

Yan Wang1,Yiru Zhu1,Soumya Sarkar1,Juhwan Lim1,Jung-In Lee1,Robert Hoye2,Manish Chhowalla1

University of Cambridge1,Imperial College London2
Atomic scale defects such as sulfur vacancies can influence the electronic structure of 2D transition metal dichalcogenides (TMDs). A relatively simple way to probe defects is by photoluminescence (PL) spectroscopy. In this study, we have probed the PL properties of 2D TMDs annealed up to 700○C in hydrogen, argon, and nitrogen atmospheres. Annealing of monolayer TMDs results in creation of defects that leads to changes in the PL spectra. We have studied monolayers of MoS<sub>2</sub> grown by chemical vapor deposition (CVD) and mechanical exfoliation. In the as-prepared samples, there is a red shift of the PL peak by ∼60meV in CVD samples compared to mechanically exfoliated samples. This is attributed to thermal strain that can be relaxed by annealing in inert environments. Annealing in argon and nitrogen also leads to narrowing of the exciton peak at ∼1.83eV up to 550○C. Above this temperature, the peak becomes broader with higher trion component. Annealing in hydrogen leads to appearance of an additional peak around 1.3 – 1.4eV. Our results suggest the creation of sulfur vacancies give rise to near infrared emission from low energy defect states.

Keywords

defects

Symposium Organizers

Zakaria Al Balushi, University of California, Berkeley
Olga Kazakova, National Physical Laboratory
Su Ying Quek, National University of Singapore
Hyeon Jin Shin, Samsung Advanced Institute of Technology

Symposium Support

Bronze
Applied Physics Reviews | AIP Publishing
ATTOLIGHT AG
Penn State 2DCC-MIP

Publishing Alliance

MRS publishes with Springer Nature