Abstract
Single-layer molybdenum diselenide(MoSe2), a two-dimension material which possesses unique optical, electrical property of transition dichalcogenides in their layered form, and a dimension with nano-scale level. In this work, high crystalline MoSe2 monolayered atomic layers on SiO2/Si and sapphire substrates have been successfully synthesized by the chemical vapor deposition (CVD) method at atmospheric pressure. Raman spectroscopy reveals that the as-grown ultrathin MoSe2 layers change from single layer to few layers. Photoluminescence (PL) spectroscopy demonstrates that while the multi-layers MoSe2 show weak emission peak, the monolayer has a much stronger emission peak at ~1.56 eV. Our results provide some general guidelines for MoSe2 monolayer synthesis. In addition, we report on the fabrication and optoelectronic properties of phototransistors based on monolayered MoSe2 back-gated field-effect transistors, with a mobility of 0.9 cm2 V−1 s−1 at room temperature. The devices exhibit a good photoresponsivity of 43.21 mA/W (using a 633 nm laser at a laser power of 2.47×〖10〗^(-4) W and a gate bias of -5 V)suggesting that MoSe2 monolayer is a promising material for photodetection applications.