Temperature-Dependent Phonons and Photoluminescence of WS₂ Monolayer to Bulk rown by CVD.

WS₂ is a layered material with unique band gap properties, making it highly promising for developing advanced electronics and optical devices. While bulk WS₂ has an indirect band gap in the near-infrared, monolayer WS₂ has a direct band gap in the visible spectrum. The optical and bandgap characteristics of WS₂ can be temperature dependent. Understanding the temperature-dependent phonon properties of materials is crucial for managing heat in electronic devices, as they impact thermal properties and scattering effects. In addition, self-heating can alter the vibrational properties of WS₂ layers, and the way electrons and phonons interact. Further, understanding the temperature-dependent A and B excitonic peaks is significant in device applications. Temperature-dependent photoluminescence and Raman spectroscopy can be utilized to identify these materials' different optical transitions and phonon properties. In this study, we will present a systematic analysis of temperature-dependent bandgap, optical transitions (including A and B exciton), electron-phonon coupling, and strain effect of WS₂ grown by chemical vapor deposition. The layers will be analyzed using photoluminescence and Raman spectroscopy techniques.