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

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 similar to 2.7 X 10(13) 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.NSFC for Excellent Young Scholars [51422201]; Program of the NSFC [61505026, 61604037, 61574031, 11604044, 51602028]; "111" Project [B13013]; Fund from Jilin Province [20160520009JH, 20160520115JH, 20160520114JH]; Fundamental Research Funds for the Central Universities [2412017FZ010, 2412016KJ017]; Ministry of Science and Technology [2016YFA0200700, 2017YFA0205004]; National Natural Science Foundation of China [21673054]; Key Research Program of Frontier Science, CAS [QYZDB-SSWSYS031]; Open Project of Key Laboratory for UV-emitting Materials and Technology of Ministry of Education [130028699]; Singapore National Research Foundation under NRF RF Award [NRF-RF2013-08]SCI(E)ARTICLE3327402-27408