Shuai Zhang,1 Chenguang Wang,2 Ming-Yang Li,3,4 Di Huang,1 Lain-Jong Li,4 Wei Ji,2* Shiwei Wu1,5*
1State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (MOE), and Department of Physics, Fudan University, Shanghai 200433, China
2 Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing 100872, China
3 Research Center for Applied Sciences, Academia Sinica, Taipei 10617, Taiwan
4 Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
5 Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
DOI:10.1103/PhysRevLett.119.046101 Publication Date: July 25, 2017
The atomic and electronic structure of intrinsic defects in WSe2 monolayer grown on graphite was revealed by low temperature scanning tunneling microscopy and spectroscopy. Instead of chalcogen vacancies that prevail in other transition metal dichalcogenide materials, intrinsic defects in WSe2 arise surprisingly from single tungsten vacancies, leading to the hole (p-type) doping. Furthermore, we found these defects to dominate the excitonic emission of WSe2 monolayer at low temperature. Our work provided the first atomic-scale understanding of defect excitons and paved the way toward deciphering the defect structure of single quantum emitters previously discovered in WSe2 monolayer.