Growth of MoSe2 Film and Graphene: MoSe2 films were deposited on the Si substrate by RF magnetron sputtering (Kurt J Lesker, PVD 75) using a 2 in. MoSe2 target (ZhongNuo Advanced Material (Beijing) Company). The RF power was kept at 50 W with a direct current (DC) bias voltage of 225 V. The pressure in the chamber was 3 mTorr during deposition, and the substrate temperature was controlled to be 400 °C. To increase the quality of MoSe2 film, the as‐prepared MoSe2 films were annealed in a rapid thermal process system (RTP‐500V) at 800 °C for 30 min. Graphene used here was synthesized by CVD method using a mixed gas of H2 (3 sccm) and CH4 (50 sccm) as gas source at 1000 °C, and a 25 μm thick copper foil was used as the catalyst substrate.