Approaching the Intrinsic Limit in Transition Metal Diselenides via Point Defect Control
Approaching the Intrinsic Limit in Transition Metal Diselenides via Point Defect Control
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DOI：
10.1021/acs.nanolett.9b00985
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发表时间：
2019-07-01
期刊：
影响因子：
10.8
通讯作者：
Pasupathy, Abhay N.
中科院分区：
文献类型：
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作者：
Edelberg, Drew;Rhodes, Daniel;Pasupathy, Abhay N.
二维（2D）过渡金属二硫属化物（TMD）基半导体材料由于其新颖的光学和电学性质以及潜在的应用前景而引起了人们极大的兴趣。在这项工作中，我们的特点的原子和电子性质的本征点缺陷中发现的这些材料的单晶合成两种不同的方法，化学气相传输和自通量生长。使用扫描隧道显微镜（STM）和扫描透射电子显微镜（STEM）的组合，我们表明，在这些材料中的两个主要的本征缺陷是金属空位和硫属元素反位。通过控制合成条件，我们可以将缺陷浓度从10（13）/cm（2）以上降低到10（11）/cm（2）以下。因为这些点缺陷作为激子的非辐射复合的中心，所以材料质量的这种改进导致辐射复合效率的百倍增加
Two dimensional (2D) transition-metal dichalcogenide (TMD) based semiconductors have generated intense recent interest due to their novel optical and electronic properties and potential for applications. In this work, we characterize the atomic and electronic nature of intrinsic point defects found in single crystals of these materials synthesized by two different methods, chemical vapor transport and self-flux growth. Using a combination of scanning tunneling microscopy (STM) and scanning transmission electron microscopy (STEM), we show that the two major intrinsic defects in these materials are metal vacancies and chalcogen antisites. We show that by control of the synthetic conditions, we can reduce the defect concentration from above 10(13)/cm(2) to below 10(11)/cm(2). Because these point defects act as centers for nonradiative recombination of excitons, this improvement in material quality leads to a hundred-fold increase in the radiative recombination efficiency