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Controlled Gas Molecules Doping of Monolayer MoS2 via Atomic-Layer-Deposited Al2O3 Films

Li, Yuanzheng, Li, Xinshu, Chen, Heyu, Shi, Jia, Shang, Qiuyu, Zhang, Shuai, Qiu, Xiaohui, Liu, Zheng, Zhang, Qing, Xu, Haiyang, Liu, Weizhen, Liu, Xinfeng, Liu, Yichun
ACS applied materials & interfaces 2017 v.9 no.33 pp. 27402-27408
aluminum oxide, electrical properties, models, nanospheres, oxygen, photoluminescence, semiconductors
MoS₂ as atomically thin semiconductor is highly sensitive to ambient atmosphere (e.g., oxygen, moisture, etc.) in optical and electrical properties. Here we report a controlled gas molecules doping of monolayer MoS₂ via atomic-layer-deposited Al₂O₃ films. The deposited Al₂O₃ films, in the shape of nanospheres, can effectively control the contact areas between ambient atmosphere and MoS₂ that allows precise modulation of gas molecules doping. By analyzing photoluminescence (PL) emission spectra of MoS₂ with different thickness of Al₂O₃, the doped carrier concentration is estimated at ∼2.7 × 10¹³ cm–² based on the mass action model. Moreover, time-dependent PL measurements indicate an incremental stability of single layer MoS₂ as the thicknesses of Al₂O₃ capping layer increase. Effective control of gas molecules doping in monolayer MoS₂ provides us a valuable insight into the applications of MoS₂ based optical and electrical devices.