Manganese and chromium doping in atomically thin MoS2

Recently, two-dimensional materials have been attracting increasing attention because of their novel properties and promising applications. However, the impurity doping remains a significant challenge owing to the lack of the doping strategy in the atomically thin layers. Here we report on the chromium (Cr) and manganese (Mn) doping in atomically-thin MoS₂ crystals grown by chemical vapor deposition. The Cr/Mn doped MoS₂ samples are characterized by a peak at 1.76 and 1.79 eV in photoluminescence spectra, respectively, compared with the undoped one at 1.85 eV. The field-effect transistor (FET) devices based on the Mn doping show a higher threshold voltage than that of the pure MoS₂ while the Cr doping exhibits the opposite behavior. Importantly, the carrier concentration in these samples displays a remarkable difference arising from the doping effect, consistent with the evolution of the FET performance. The temperature-dependent conductivity measurements further demonstrate a large variation in activation energy. The successful incorporation of the Mn and Cr impurities into the monolayer MoS₂ paves the way towards the high Curie temperature two-dimensional dilute magnetic semiconductors.

近年来，二维材料由于其新颖的物理特性和巨大的应用前景受到越来越多的关注。然而，由于缺少有效的掺杂方式，二维材料中的磁性元素掺杂仍然是一个重大挑战。这里，我们报导通过化学气相沉积方法生长和掺杂的二硫化钼原子晶体。与未掺杂的样品相比，/掺杂的样品的光致发光谱特征峰分别位于1.76/ 1.79eV（未掺杂的峰位为1.85eV）。并且，基于锰掺杂的场效应晶体管（FET）器件具备比纯二硫化钼更高的阈值电压，而铬掺杂表现出相反的行为。更重要地是，这些样品中的载流子浓度与掺杂元素紧密相关，呈现出巨大差异，并与FET性能演变保持一致。电导随温度的变化测量进一步证明了杂质激活能的不同。本文成功将锰和铬元素掺入到单层二硫化钼中，为探索和发现高居里温度二维稀磁半导体奠定了实验基础。

通信作者：修发贤，复旦大学，Email：[e-mail]

Cite this article：Ce Huang, Yibo Jin, Weiyi Wang, Lei Tang, Chaoyu Song and Faxian Xiu. Manganese and chromium doping in atomically thin MoS₂. Journal of Semiconductors, 2017, 38(3): 033004

Fig. 1. Schematic view of the synthesis and the optical properties of the samples. (a) A CVD growth process. Mn and Cr are used as the impurity dopants. (b)-(d) Optical images of the pure/Mn-doped/Cr-doped MoS₂ on SiO₂/Si substrate, respectively. (e) Photoluminescence spectra of three types of samples. Cr-doped MoS₂ shows a strong photoluminescence at 1.76 eV while the Mn-doped MoS₂ has a peak at 1.79 eV.

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