Quick Optical Identification of the Defect Formation in Monolayer WSe2 for Growth Optimization
Quick Optical Identification of the Defect Formation in Monolayer WSe2 for Growth Optimization
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快速光学识别单层 WSe2 中的缺陷形成以优化生长
DOI：
10.1186/s11671-019-3110-z
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发表时间：
2019-08-14
影响因子：
--
通讯作者：
Tao, Shaohua
中科院分区：
文献类型：
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作者：
Fang, Long;Chen, Haitao;Tao, Shaohua
自下而上的外延技术已被广泛应用于过渡金属二卤化物(TMDCs)的生长。然而，这种方法通常会导致晶体中存在高密度的缺陷，从而限制了其光电性能。在这里，我们通过拉曼光谱和光致发光光谱相结合的研究，展示了生长温度对单层WSe_2中缺陷形成、光学性能和晶体稳定性的影响。我们发现，单层WSe2中缺陷的形成和分布与生长温度密切相关。这些缺陷的密度和分布可以通过调节生长温度来控制。时效实验直接证明了这些缺陷是分解过程的活性中心。相反，在最佳条件下生长的WSe2单层在室温下表现出以中性激子为主的强烈而均匀的发射。研究结果为优化TMDCs的生长提供了有效的途径。
Bottom-up epitaxy has been widely applied for transition metal dichalcogenides (TMDCs) growth. However, this method usually leads to a high density of defects in the crystal, which limits its optoelectronic performance. Here, we show the effect of growth temperature on the defect formation, optical performance, and crystal stability in monolayer WSe2 via a combination of Raman and photoluminescence (PL) spectroscopy study. We found that the defect formation and distribution in monolayer WSe2 are closely related to the growth temperature. These defect density and distribution can be controlled by adjusting the growth temperature. Aging experiments directly demonstrate that these defects are an active center for the decomposition process. Instead, monolayer WSe2 grown under optimal conditions shows a strong and uniform emission dominated by neutral exciton at room temperature. The results provide an effective approach to optimize TMDCs growth.