Single photon emitters in monolayer WSe₂

Chiao-Tzu Huang^1,2*, Chien-Ju Lee¹, Shih-Chu Lin¹, Shih-Ting Wang¹, Wen-Hao Chang^1,2

¹Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan

* Presenter:Chiao-Tzu Huang, email:chiaotzu.sc11@nycu.edu.tw

Monolayer tungsten diselenide (WSe₂) can generate single photon emissions at low temperatures. It has been demonstrated that by creating localized strain field in mono- or bilayer WSe₂, single photon emitters (SPEs) can be created artificially. However, the fundamental mechanism for this phenomenon has not been fully understood so far. Here we present the creation of these quantum-dot-like SPEs in WSe₂ grown by chemical vapor deposition (CVD). By transferring CVD-grown WSe₂ onto hollow structures etched on SiO₂/Si substrate, spatially and spectrally isolated SPEs can be created at the vicinity of these hollow structures. Second-order correlation function measurements revealed clear signature photon anti-bunching, indicating the single-photon nature of these emitters. Two types of emitters were identified through polarization-resolved photoluminescence and spectral diffusion measurements. Beside the commonly reported SPEs with two non-degenerate, cross-linearly-polarized transitions due to the exciton exchange interaction, spectral lines without fine-structure splitting at longer wavelength were observed. Magneto-optical and temperature dependent photoluminescence were measured to characterize these two types of SPEs.

Keywords: TMDs, Quantum emitter