Approaching the intrinsic photoluminescence linewidth in transition metal dichalcogenide monolayers
Approaching the intrinsic photoluminescence linewidth in transition metal dichalcogenide monolayers
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DOI：
10.1088/2053-1583/aa6aa1
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发表时间：
2017-09-01
期刊：
影响因子：
5.5
通讯作者：
Hone, James C.
中科院分区：
文献类型：
--
作者：
Ajayi, Obafunso A.;Ardelean, Jenny V.;Hone, James C.
单层过渡金属二硫族化合物（TMDCs）的激子态是近年来广泛关注的课题。然而，由于外部环境的不均匀性的影响，它们的内在特性可能会被掩盖。本文报道了一种制备高质量的光致发光（PL）线宽接近固有极限的TMDC单层材料的方法。我们发现，六方氮化硼（h-BN）的包封使PL线宽急剧减小，烷基单层对氧化物衬底的钝化进一步减小了线宽，并使带电激子（trion）峰最小化。这些样品制备方法的组合导致PL发射的空间变化大大减小，半最大值全宽度低至1.7 meV。对PL线形状的分析得出均匀宽度为1.43 +/- 0.08 meV，非均匀展宽为1.1 +/- 0.3 meV。
Excitonic states in monolayer transition metal dichalcogenides (TMDCs) have been the subject of extensive recent interest. Their intrinsic properties can, however, be obscured due to the influence of inhomogeneity in the external environment. Here we report methods for fabricating high quality TMDC monolayers with narrow photoluminescence (PL) linewidth approaching the intrinsic limit. We find that encapsulation in hexagonal boron nitride (h-BN) sharply reduces the PL linewidth, and that passivation of the oxide substrate by an alkyl monolayer further decreases the linewidth and also minimizes the charged exciton (trion) peak. The combination of these sample preparation methods results in much reduced spatial variation in the PL emission, with a full-width-at-half-maximum as low as 1.7 meV. Analysis of the PL line shape yields a homogeneous width of 1.43 +/- 0.08 meV and inhomogeneous broadening of 1.1 +/- 0.3 meV.