摘要
二维过渡金属硫族化合物(TMDCs)材料被认为是拓展摩尔定律的极具前景的候选材料.然而,该材料的低光致发光效率严重限制了其实际应用,其本质源于材料制备中不可避免引入的缺陷.在本文中,我们报道了一种Sr掺杂单层MoS_(2)的有效缺陷工程策略,该策略在实验上通过简便的化学气相沉积(CVD)一步法成功实现.所制备的具有亚毫米(~324μm)级的大尺寸样品的光致发光可实现高达两个数量级的增强,并伴随着载流子寿命的显著增强.这一现象主要归因于Sr掺杂后MoS_(2)体系中其三激子向激子转换.与此同时,掺杂样品的辐射质量和稳定性也显著提升.第一性原理计算进一步阐明了其调控机制,即在MoS_(2)中引入适当互补缺陷能级与其自身的缺陷能级协同,从而可调节其载流子组分,以实现光致发光的显著增强.此外,我们的缺陷工程策略也适用于其他掺杂剂,如钙掺杂剂.我们的工作报告了一种可以显著提升单层MoS_(2)的荧光性能的有效缺陷工程策略,这为设计和调控二维TMDCs的光电特性提供一种极具前途的方法.
Two-dimensional(2D)transition metal dichalcogenide(TMDC)materials are considered as promising candidates to extend Moore’s Law.However,the low photoluminescence(PL)quantum yield due to the inevitable defects during material preparation severely restricts its practical applications.Here,we report an effective defect engineering strategy for Sr-doped MoS_(2) that has been successfully achieved by a facile one-step chemical vapor deposition(CVD)method.PL enhancement up to two orders of magnitude,along with prolonged carrier lifetime,is obtained by doping the sample with a lateral size up to sub-millimeter level(~324μm).Such an observed phenomenon is attributed to the transformation of negative trions to neutral excitons.Meanwhile,the radiation quality and stability of the doped samples are significantly improved.First-principles calculations further elucidate the underlying mechanism,that is,the introduction of appropriate complementary defect energy levels in MoS_(2) synergizes with its own defect energy levels to enhance the PL emission,rather than a simple doping effect.In addition,our defect strategy can also be applied to other dopant like calcium atoms.Our work demonstrates an effective defect engineering strategy to improve the PL performance of 2D TMDCs,which provides a promising approach for designing and engineering their optoelectronic properties for potential applications.
作者
陈荧
黄卓睿
刘华伟
喻国粮
张金鼎
徐哲元
陈明星
李东
马超
黄明
朱小莉
陈舒拉
蒋英
潘安练
Ying Chen;Zhuorui Huang;Huawei Liu;Guoliang Yu;Jinding Zhang;Zheyuan Xu;Mingxing Chen;Dong Li;Chao Ma;Ming Huang;Xiaoli Zhu;Shula Chen;Ying Jiang;Anlian Pan(Key Laboratory for Micro-Nano Physics and Technology of Hunan Province,Hunan Institute of Optoelectronic Integration,School of Physics and Electronics,College of Materials Science and Engineering,Hunan University,Changsha 410082,China;School of Physics and Electronics,Hunan Normal University,Changsha 410081,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)
基金
supported by the National Natural Science Foundation of China(62375079,52072117,62375081,52221001,51972105,62090035,U19A2090,and 61905071)
the National Key R&D Program of China(2022YFA1204300)
the Key Program of Science and Technology Department of Hunan Province(2019XK2001 and 2020XK2001)
the Key Research and Development Plan of Hunan Province(2023GK2012)
the Open Project Program of Key Laboratory of Nanodevices and Applications,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(22ZS01)
the Hunan Provincial Natural Science Foundation of China(2021JJ30132)
the China Scholarship Council.
