[11a-N302-1~11] 17.3 Layered materials

▼ [11a-N302-4] Synthesis of 2D MoS₂ and WS_1-xSe_x thin films by Mist-CVD

〇(D)Abdul A Kuddus¹, Arifuzzaman Rajib¹, Kizaki Ryotaro¹, Yokoyama Kojun¹, Keiji Ueno¹, Hajime Shirai¹ (1.Saitama University)

Keywords:Monolayer MoS2, Mist-CVD, MIS-FET

We have studied the synthesis of 2D MoS₂ atomic layer thin films by mist CVD from ammonium tetrathiomolybdate (NH₄)₂MoS₄ using layer by layer (LbL) method. Previously, we presented (1) the number of stacking layers of MoS₂ flakes under the LbL mode was varied from atomic mono layer to 4 to 5 layers by varying t₂, repetition cycles of precursor mist supply N, and solution precursors concentration. (2) The average size of atomic MoS₂ monolayer flakes deposited using LbL mode on th-SiO₂ and ATO dielectric layers increased to 20 to 30 and 60 to70 µm, respectively with relatively uniform size distribution. (3) Atomic MoS₂ monolayer-based FETs exhibited a mobility of 31 to 40 (43 to 55) cm²/Vs with a V_th of -1.6 (-0.5 V), an on/off ratio of 3.0 × 10^4 (3.5 × 10^5), and SS of 0.80 (0.11) V per dec. for th-SiO₂ (ATO) gate insulator layers without mechanical exfoliation [1]. In this study, we attempt to further increase in the crystalline grain size of MoS₂ flake and extend the fabrication of WS₂ based ternary alloy, WS_1-xSe_x thin layers by LbL method.