利用氫鹵酸處理使原子級單層二硒化鉬之光致螢光效應提升

Photoluminescence Enhancement of Monolayer MoSe2 by Hydrohalic Acid Treatment

原子級厚度的二維層狀過渡金屬硫化物具有獨特的光電特性，因此被視為在未來的電子及光電產業的關鍵材料。雖然目前有許多製程技術可以提供成長高品質的單晶二維過渡金屬硫化物，但仍難免在材料中產生結構缺陷，這些缺陷會大量的捕捉自由載子與局部激子而導致導帶至價帶的複合減少。在本研究中，我們利用簡易的氫鹵酸處理方式，可以有效地修補樣品中的結構缺陷，進而使整體的發光效益增加30倍以上。而從我們的研究得知，氫鹵酸處理不僅可以修補材料表面的結構缺陷，也可以調變二維過渡金屬硫化物中的摻雜比例，操控其相對應的光學發光現象，提供一個可調整與控制二維過渡金屬硫化物材料本質及光電特性的可行方法，對於未來開發二維材料在微型光電元件的應用極為重要。 Atomically thin two-dimensional transition-metal di-chalcogenides(TMDCs) have attracted much attention due to their unique electronic and optical properties for future optoelectronic devices. Although there are many promising fabrication processes have been employed to produce high quality TMDCs layers with a scalable size and a controllable thickness, the grown TMDC monolayers may still incorporate unwanted structural defects. These defects signifi cantly trap free charge carriers and localize excitons, leading to the smearing of free band-toband exciton emission. In this paper, we introduce a simple hydrohalic acid treatment to effi ciently suppress the trap state emission and promote the neutral exciton and trion emission in defective MoSe2 monolayers. The overall photoluminescence intensity at room temperature can be enhanced by a factor of 30. Our results suggest that the hydrohalic acid treatment not only reduces the structural defects, but also modifi es the corresponding optoelectronic characteristics in fabricated MoSe2 layers, providing further insights of the control and tailoring the exciton emission from monolayer TMDCs.